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Behaviour of some trace metals in sediments of the Fraser River delta-front, southwestern British Columbia 1977

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BEHAVIOUR OF SOME TRACE METALS IN SEDIMENTS OF THE FRASER RIVER DELTA-FRONT, SOUTHWESTERN BRITISH COLUMBIA by DAVID AUSTIN GRIEVE B . S c , Univer s i ty of B r i t i s h Columbia, 1974 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n THE FACULTY OF GRADUATE STUDIES (Department of Geologica l Sciences) We accept t h i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA January, 1977 © D a v i d Austin Grieve, 1977 In presenting th is . t h e s i s - i n p a r t i a l fu l f i lment o f the requirements for an advanced degree at the Un ivers i ty of B r i t i s h Columbia, I agree that the L ibrary sha l l make it f ree ly ava i l ab le for reference and study. I fur ther agree that permission for extensive copying of th is thesis for scho la r ly purposes may be granted by the Head of my Department or by his representat ives . It is understood that copying or pub l i ca t ion of th is thes is fo r f i n a n c i a l gain sha l l not be allowed without my writ ten permission. Department of G e o l o g i c a l S c i e n c e s The Univers i ty of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date January 11, 1977 ABSTRACT i i Co, Cu, Fe, Mn, N i , Pb and Zn contents, both i n t o t a l and p a r t i a l extract ions , have been determined for i n t e r - t i d a l and foreslope s u r f i c i a l sediments of the Fraser River act ive de l ta - f ront . In conjunction with analys i s of subsurface sediments and water and suspended sediment from the main channel, these data suggest controls on metal contents and d i s t r i b u t i o n . An inverse r e l a t i o n between t o t a l metal contents and sand content of sediment i s demonstrated i n geographic d i s t r i b - utions and c o r r e l a t i o n analysis of metal data. R e l a t i v e l y great- er concentrations of metals i n hydrous oxide phases and d e t r i t a l minerals of the s i l t - p l u s - c l a y f r ac t ion account for t h i s r e l a t - ionship. Trace metals i n heavy minerals of the sand f r ac t ion p a r t i a l l y negate the;', g ra in-s ize e f fec t . Adsorbed metals are an i n s i g n i f i c a n t quantity (excepting Mn) except i n two samples from an area rece iv ing eff luent from the Iona Is land sewage t rea t - ment p lant . V a r i a t i o n of trace metal contents in short cores i s general ly re la ted to t r ans i t i ons i n sediment texture. Some metal may be mobil ized and los t subsequent to b u r i a l , although th i s conclusion i s contingent on the assumption that trace metal input to de l ta- f ront sediments i s constant over time. One core c o l l - ected near Iona Is land, however, contains evidence that t h i s assumption i s not t o t a l l y v a l i d . Scavenging of Zn, and probably other trace metals, by newly-formed hydrous Fe (and poss ibly Mn) oxides takes place in brackish condit ions wi th in the main channel. In conjunction with phys ica l processes which increase residence times of s ed i - ments in the estuarine port ions of the r i v e r , th i s process accou nts for removal of a s izeable f r ac t ion of d i s so lved metal . Desorption of trace metals occurs in the channel and i n Georgia S t r a i t , although probably to a somewhat lesser extent than the sorpt ion process. In terms of metal contents and mechanisms of metal deposi t ion, the Fraser de l ta- f ront i s t y p i c a l of nearshore s e d i - ments of low clay content. Trace metal sorpt ion by various mechanisms, inc lud ing that described here, accounts for retent- ion of r iver-borne and waste metals in nearshore sediments. iv TABLE OF CONTENTS Page ABSTRACT i i LIST OF TABLES v i LIST OF FIGURES AND PLATE v i i i ACKNOWLEDGEMENTS x CHAPTER I: INTRODUCTION 1 Introduction 1 Review of Previous Work 2 Objectives and Out l ine of Study 5 CHAPTER I I : DESCRIPTION OF STUDY AREA 6 Introduction 6 Hydrology 9 Oceanography 11 Tides 11 Surface Currents 12 Interact ion of Fraser River and Georgia S t r a i t Waters 13 Sedimentology 14 Sediment Transport in the Fraser River 14 Sediment D i s t r i b u t i o n on the Act ive Delta-Front 15 Environmental Considerations 19 CHAPTER III : SAMPLING AND ANALYTICAL PROCEDURES 21 Sample C o l l e c t i o n 21 Sediments 21 Waters 23 Sample Preparation 26 Sediments 26 Waters and Suspended Sediments 26 Trace Metal Analyses 27 Sediments 27 Metal extract ion 27 Atomic absorption spectrophotometry 29 Suspended Sediments 29 Waters 32 Minera log ica l Determinations 33 S u r f i c i a l Sediments 33 Suspended Sediments 34 Grain Size Determinations 34 Loss on Ign i t ion 34 Corre l a t ion and Regression Analysis 35 V Page CHAPTER IV: TRACE METALS IN SURFICIAL SEDIMENTS OF THE FRASER RIVER DELTA-FRONT 36 Introduction 36 Results 36 Trace Metal Content and D i s t r i b u t i o n 36 Corre l a t ion and Regression Analys i s 48 Se lect ive Chemical Extrac t ion Experiments 53 Discuss ion 58 CHAPTER V: TRACE METALS IN BURIED INTERTIDAL SEDIMENTS OF THE FRASER RIVER DELTA-FRONT 70 Introduction 70 Results 70 Discuss ion 74 CHAPTER V I : INTERACTIONS BETWEEN SUSPENDED SEDIMENT AND TRACE METALS IN THE MAIN CHANNEL OF THE FRASER RIVER 78 Introduction 78 Results 79 Discuss ion 84 Sorption and Desorption of Zinc 84 Influence of Sorption-Desorption Processes on Trace Metal Content of Delta-Front Sediments 92 CHAPTER VII : MECHANISMS OF TRACE METAL DEPO- SITION IN NEARSHORE SEDIMENTS 95 Introduction 95 Discuss ion 95 Trace Metal Deposit ion i n Nearshore Sediments 95 Trace Metal Sorption i n Nearshore Waters 96 Removal of Waste Trace Metals to Nearshore Sediments 100 CHAPTER VII I : CONCLUSIONS AND SUGGESTIONS FOR FURTHER RESEARCH 102 Summary of Conclusions 102 Suggestions for Further Research 103 BIBLIOGRAPHY 105 APPENDICES. 113 Appendix A: Co, Cu, Fe(%), Mn, N i , Pb and Zn 113 Content (ppm) of Fraser Del ta- Front Sediments Appendix B: F i r s t P a r t i a l Extrac t ion 125 Experiment Results Appendix C: Co, Cu, Fe(%), Mn, N i , Pb and Zn 126 Content (ppm) of Sediment Cores from I n t e r t i d a l Regions of the Fraser Delta-Front LIST OF TABLES Table I: Instrumental conditions of atomic absorption spectrophotometry. Table I I : A n a l y t i c a l p r e c i s i o n of HN0 3-HC10 4 attack, based on analysis of 20 paired samples. Table I I I : A n a l y t i c a l p rec i s i on of f i r s t sequential extract ion experiment, based on analys i s of 6 pa ired samples. Table IV: Metal content, percent sand and loss on i g n i t i o n of Fraser de l ta- f ront sediments ( a l l data on f iner- than 80-mesh mater ia l ) . Table V: Corre l a t ion matrix for i n t e r t i d a l sediments c o l l e c t e d i n February, 1974 ( f iner than 80-mesh mater ia l ; n=68; r=.24 s i g n i f i c a n t at 95% confidence l e v e l ) . Table VI : Cor re l a t ion matrix for fore-slope sediments c o l l e c t e d i n March, 1974 ( f iner than 80-mesh mater ia l ; n=218; r= . l3 s i g n i f i c a n t at 95% confidence l e v e l ) . Table VI I : Mul t ip l e regression equations, i n t e r t i d a l sediments c o l l e c t e d i n February 1974 ( f iner than 80-mesh mater ia l ; n=68). Table V I I I : M u l t i p l e regression equations, fore-slope sediments c o l l e c t e d in March 1974 ( f iner than 80-mesh mater ia l ; n=218). Table IX: Observed, predicted and re s idua l values from regression equations (Table VII) for t i d a l f l a t s tat ions affected by discharge of meta l - r ich sewage e f f luent . Table X: Mean and range of metal values i n seq- uent i a l extracts of de l ta- f ront sedim- ents (n=37). Table XI: Sequential extract ion of t i d a l f l a t sediments from two s tat ions affected by discharge of meta l - r ich sewage e f f luent . Table XIX: Conductivi ty at lm depth, and d i s so lved , t o t a l p a r t i c u l a t e , and HHA-extractable par t i cu la te metal concentrations in the Fraser River . v i i Page Table XII : Sequential extract ion of de l t a - 59 front sediments; p a r t i t i o n i n g of metals between KHA-extractable and HF-HN0 3 -HC10 4 -extractable s i l t - p l u s - clay and sand. Table XIII : Mean t o t a l metal contents (ppm) of 61 nearshore sediments. Table XIV: Proport ion of metals (%) in hydrous ; 64 oxide phases of nearshore sediments. Table XV: Proportion of metals (%) in d e t r i t a l 64 minerals of nearshore sediments. Table XVI: Average metal content and sand content 73 of i n t e r t i d a l sediment cores. Table XVII: Predicted and res idua l values of 75 average metal contents in i n t e r t i d a l sediment cores; regression equations taken from data for February t i d a l f l a t samples. Table XVIII: Weight of suspended sediments and 82 suspended major elements i n samples from the Fraser River . 83 Table XX: Compilation of published summaries of trace metal concentrations in ocean and r i v e r waters. 98 V i l l LIST OF FIGURES AND PLATE Page Figure 1: B r i t i s h Columbia and lower Fraser 7 v a l l e y ( i n s e t ) , showing the Fraser River and major t r i b u t a r i e s and d i s t r i b u t a r i e s . Figure 2: The Fraser River de l ta with 8 general ized s u r f i c i a l geology. Figure 3: Discharge hydrograph for 1970, 10 Fraser River at Hope (Hoos and Packman, 1974). Figure 4: Locations of s u r f i c i a l sediment 22 samples (February and March sampling s e r i e s ) , Fraser de l ta- f ront i n t e r t i d a l and fore-slope regions ( o r i g i n of coordinates at 4 9 ° 0 0 ' N , 123025'W). Figure 5: Locations of i n t e r t i d a l sediment 24 short core samples. Figure 6: Diagram of sediment coring device used 25 i n t h i s study. Figure 7: D i s t r i b u t i o n of Co i n the minus80-mesh 39 f r ac t ion of Fraser de l ta- f ront s u r f i c i a l sediments (February and March sampling s e r i e s ) . Figure 8: D i s t r i b u t i o n of Cu i n the minus80-mesh 40 f r a c t i o n of Fraser de l ta- f ront s u r f i c i a l sediments (February and March sampling s e r i e s ) . Figure 9: D i s t r i b u t i o n of Fe i n the minus80-mesh 41 f r a c t i o n of Fraser de l ta- f ront s u r f i c i a l sediments (February and March sampling s e r i e s ) . Figure 10: D i s t r i b u t i o n of Mn i n the minus80-mesh 42 f r a c t i o n of Fraser de l ta- f ront s u r f i c i a l sediments (February and March sampling s e r i e s ) . Figure 11: D i s t r i b u t i o n of Ni in the minus80-mesh 43 f r a c t i o n of Fraser de l ta- f ront s u r f i c i a l sediments (February and March sampling s e r i e s ) . Figure 12: Figure 13: Figure 14: Figure 15: Figure 16: Figure 17: Figure 18: Figure 19: Plate 1: D i s t r i b u t i o n of Pb i n the minus80-mesh f r a c t i o n of Fraser de l ta- f ront s u r f i c i a l sediments (February and March sampling s e r i e s ) . D i s t r i b u t i o n of Zn in the minus80-mesh f r a c t i o n of Fraser de l ta- f ront s u r f i c i a l sediments (February and March sampling s e r i e s ) . Pb and Zn contents (ppm) of se lected s u r f i c i a l sediments from the fore- slope west of Sturgeon Bank (March sampling s e r i e s ) . D i s t r i b u t i o n of sand (plus270-mesh) i n the minus80-mesh f r a c t i o n of Fraser de l ta- f ront s u r f i c i a l sediments (February and March sampling s e r i e s ) . D i s t r i b u t i o n of normalized res iduals of the regression of Zn on sand content (March sampling s e r i e s ) . Schematic sect ion of Co, Zn and Cu values (ppm) i n 5cm-subsamples of subsurface sediments from Roberts Bank. Sampling s tat ions in the Fraser River with conduct iv i ty (umho/cm) i n parent- heses . Var ia t ions in Fraser River water contents of suspended sediment; t o t a l suspended Fe and Zn; hydro- xylamine hydrochlor ide-acet ic a c id - extractable Zn; and dissolved Zn. Upper port ion of Cores 34, 38 and 16 ( l e f t to r ight ) c o l l e c t e d from three contrast ing environments on Roberts Bank. X ACKNOWLEDGEMENTS The a u t h o r i s i n d e b t e d t o t h e f o l l o w i n g p e o p l e f o r a s s i s t a n c e d u r i n g t h e s t u d y . Dr. W.K. F l e t c h e r a c t e d as a d v i s o r , a u t h o r i t y and f r i e n d i n every p o s s i b l e way. Dr. J.L. L u t e r n a u e r , b e s i d e s making the s t u d y p o s s i b l e , p r o v i d e d f i e l d s u p e r v i s i o n and s u p p o r t , and ca m a r a d e r i e . D r s . J.W. Murray, W.C. Barnes and M.A. Barnes were i n s t r u m e n t a l i n g e t t i n g the auth o r i n v o l v e d i n the p r o j e c t , and p r o v i d e d a d v i c e and encouragement t h r o u g h o u t . Mr. M. Waskett-Myers a s s i s t e d i n s a m p l i n g and a n a l y s e s ; Mr. A. D h i l l o n a lso h e l p e d on a n a l y s e s and p r o v i d e d good advice* on a n a l - y t i c a l t e c h n i q u e s . Dr. A.G. Lewis gave a d v i c e on w a t e r s a m p l i n g and c a r r i e d out d i s s o l v e d o r g a n i c carbon a n a l y s e s i n h i s l a b . Dr. L.M. L a v k u l i c h a d v i s e d on x - r a y d i f f r a c t i o n t e c h n i q u e s , and made h i s equipment a v a i l a b l e f o r use. Dr. S.J. Hoffman a d v i s e d on computer programming. The t e c h n i c a l s t a f f of t h e G e o l o g i c a l S c i e n c e s Department, e s p e c i a l l y Mr. R. Rodway, Mr. G. McLean and Mr. B. McDonald, l e n t t h e i r p r a c t i c a l e x p e r t i s e . F i n a n c i a l a s s i s t a n c e was p r o v i d e d by t h e Department o f S u p p l i e s and S e r v i c e s ( t h r o u g h Dr. J.L. L u t e r n a u e r o f t h e Ge o l o g i c a l Survey o f Canada, Vancouver, B r i t i s h C o l u m b i a ) , t h e G r e a t e r Vancouver R e g i o n a l D i s t r i c t , and the B r i t i s h Columbia Department o f Lands, F o r e s t s , and Water Re s o u r c e s . CHAPTER I: INTRODUCTION Introduction D e l t a i c and estuarine environments, despite t h e i r b i o l o g i c a l importance and v u l n e r a b i l i t y to contamination, have only recent ly begun to receive the at tent ion of sedimentary geochemists. Studies of trace metal behaviour i n these regions are v i t a l to our understanding of biogeochemical cyc le s , for many changes i n metal form and phase can be observed i n these t r a n s i t - ion zones. Such changes affect a v a i l a b i l i t y of metals to organis- ms and food chains, and also determine, i n conjunction with phys- i c a l processes, geographic d i s t r i b u t i o n s and residence times of metals i n the nearshore environment. Sediments act as temporary s inks for trace metals, and thus t h e i r metal content r e f l e c t s p h y s i c a l , chemical and b i o l o g - i c a l processes a f fect ing metal behaviour. In p a r t i c u l a r , they r e f l e c t processes which remove metals from the dissolved phase, and processes of sediment. t ransportat ion and depos i t ion . Since the bulk of r iver-borne dissolved metals i s removed from so lut ion in or near estuaries (Chester, 1965; Turekian, 1971) and since the majority of marine sediments are deposited in nearshore regions near r i v e r mouths, de l ta- f ront sediments are an i d e a l subject for marine metal-sediment i n t e r a c t i o n s tudies . The Fraser de l ta i s an e c o l o g i c a l l y and economically important region. Pressures of urban expansion and i n d u s t r i a l development have a l tered or threaten to a l t e r natural balances and necessitate de ta i l ed study of a l l aspects of the chemical, b i o l o g i c a l and phys ica l environments. This study of trace metal 2 d i s t r ibu t ions and forms i n de l ta- f ront sediments w i l l , i t i s hoped, be useful to s c i e n t i s t s and administrators concerned with the Fraser de l ta region. Review of Previous Work Papers report ing t o t a l metal contents of nearshore sediments are common. For example, unpolluted sediments from Conception Bay (S l a t t , 1974) display strong corre la t ions between t o t a l trace metal contents and clay and organic-carbon content. Concentrations of t o t a l Co, Cu, Fe, Mn, Pb and Zn (but not Ni) in Solway F i r t h sediments (Perkins et aJ, 1973) are s i m i l a r l y corre la ted with f ine-gra ined mater ia l . Studies which attempt to extract various phases of metal from sediment are more rare . Chester and Stoner (1975) treated sediments from the Severn estuary with hydroxylamine- hydrochloride i n ace t i c ac id to extract adsorbed metals and those associated with i ron and manganese oxides. They found that the metals most concentrated in the extract are Mn, Pb and Zn. A complex chemical f r ac t ionat ion of Los Angeles Harbour sediments was c a r r i e d out by Gupta and Chen (1975). The phases extracted include d i s so lved ( i n t e r s t i t i a l water), water-soluble , exchange- able, carbonate, e a s i ly reduc ib le , organic and sulphide , moder- ately reducib le , and l ithogenous. Exchangeable metals comprise non-detectable or i n s i g n i f i c a n t proportions of t o t a l metals, while lithogenous metals (those wi th in d e t r i t a l minerals) are the major f r ac t ion of Cu, Fe, Mn and N i , but not Pb and Zn. Large proport- ions of the l a t t e r two metals are bound in amorphous Fe and Mn 3 oxides. Transport of metals in r i v e r s and through estuaries has received considerable at tent ion i n recent years. Gibbs (1973) invest igated mechanisms of trace metal transport i n the Amazon and Yukon Rivers . Metals were found to ex i s t predominantly in d e t r i t a l suspended p a r t i c l e s and i n amorphous coatings of i ron and manganese oxides, with dissolved metals also cons t i tu t ing a s i g n i f i c a n t proport ion. River-borne di s so lved i ron i s removed from so lut ion i n several estuarine regions inc lud ing the Gulf of St . Lawrence (Bewers et a l , 1974), Saguenay f jord (Yeats and Bewers, 1976), the Beaulieu estuary (Hol l iday and L i s s , 1976), the Merrimack estuary (Boyle ejt a l , 1974), the M u l l i c a estuary (Coonley et a l , 1971) and three Puerto Rican estuaries (Lowman et a l , 1966). Rem- oval of i ron was not observed i n the Rhine estuary (Eisma, 1975). Manganese in Naragansett Bay (Graham et a l , 1976) and the Columbia estuary (Evans and C u t s h a l l , 1973) i s mobi l ized from sediment at low s a l i n i t i e s , and, i n the former case, i s in turn removed from so lut ion at higher s a l i n i t i e s . Removal of d i s so lved manganese has been in fer red i n three Puerto Rican estuaries (Lowman et _al, 1966). Manganese in the Beaulieu estuary behaves conserva- t i v e l y (Hol l iday and L i s s , 1976), that i s , no loss or gain of d i s so lved manganese occurs, other than that accounted for by mixing of fresh and sa l ine waters. Dissolved z inc concentrations also behave conservat ively in the Beaulieu estuary (Hol l iday and L i s s , 1976), and the Gulf of St . Lawrence (Bewers et_ al_, 1974), whereas removal of d i s so lved z inc has been reported beneath the ha loc l ine of an Alaskan f jo rd 4 ( B u r r e l l , 1973), and has been in fe r red in three Puerto Rican estuaries (Lowman e_t _al, 1966). Mob i l i z a t ion of z inc at low s a l i n i t i e s has been reported using dissolved z inc data of the Var estuary (Fukai et. a l , 1975) and the Columbia estuary (Evans and C u t s h a l l , 1973). Zinc concentrations i n bottom sediments of the Rhine and Ems estuaries (de Groot, 1973) also imply mobi l- i z a t i o n . Other trace metals have been reported to behave conserv- a t i v e l y in the Gulf of St . Lawrence (Bewers et a l , 1974), to be removed from s o l u t i o n ; i n Long Island Sound (Schutz and Turekian, 1965) and three Puerto Rican estuaries (Lowman et a l , 1966), and to be mobi l ized in the Rhine and Ems estuaries (de Groot, 1973). Knowledge of metal behaviour i n the Fraser de l ta and estuary region and southern Georgia S t r a i t i s rather sparse. Bot- tom sediments and water of the Fraser River near i t s mouth have been reported to contain contaminated l eve l s of trace metals ( H a l l et a l , 1974; H a l l and F le tcher , 1974). Benthic organisms on Sturgeon Bank contain higher concentrations of trace metals than s i m i l a r organisms from Roberts Bank and other locat ions i n B r i t i s h Columbia (Parsons et a l , 1973). Uptake of pa r t i cu l a te i ron by algae i n Georgia S t r a i t and subsequent release of d i s s- olved i ron was in fer red by Will iams and Chan (1966) to expla in seasonal var ia t ions i n these quant i t i e s . Desorption of z inc and copper from Fraser River freshet sediment i n Georgia S t r a i t was observed by Thomas (1975). 5 O b j e c t i v e s and O u t l i n e o f Study The o v e r a l l purpose o f t h i s s t u d y i s t o determine f a c t o r s w h i c h c o n t r o l c o n t e n t s and d i s t r i b u t i o n o f Co, Cu, Fe, Mn, N i , Pb and Zn i n s u r f i c i a l sediments of the F r a s e r R i v e r a c t i v e d e l t a - f r o n t . S p e c i f i c o b j e c t i v e s a r e : i ) t o determine c o n t e n t s and d i s t r i b u t i o n o f m e t a l s i n s u r f i c i a l sediment, and the c h e m i c a l and p h y s i c a l sediment f r a c t i o n s i n which the m e t a l s are bound; i i ) t o determine s u b s u r f a c e m e t a l p r o f i l e s i n d e l t a - f r o n t s e d i m e n t s ; and i i i ) t o d e t e c t changes i n m e t a l a s s o c i a t i o n i n the e s t u a r - i n e p o r t i o n o f t h e main c h a n n e l , p a r t i c u l a r l y s o r p t i o n and d e s o r p t i o n r e a c t i o n s . These o b j e c t i v e s s e r v e d as a framework f o r t h e s t u d y , and thus o r g a n i z a t i o n o f t h i s r e p o r t f o l l o w s a s i m i l a r o u t l i n e . A f t e r b r i e f d e s c r i p t i o n s o f t h e s t u d y a r e a ( C h a p t e r I I ) and f i e l d and a n a l y t i c a l t e c h n i q u e s ( C h a p t e r I I I ) , r e s u l t s and d i s c u s s i o n of s t u d y o f s u r f i c i a l sediment m e t a l c o n t e n t s and d i s t r i b u t i o n a r e p r e s e n t e d ( C h a p t e r I V ) . Chapter V p r e s e n t s r e s u l t s of t o t a l m e t a l d e t e r m i n a t i o n i n s h o r t c o r e s , and d i s c u s s i o n o f f a c t o r s i n f l u e n c - i n g m e t a l p r o f i l e s i n s u b s u r f a c e sediments. Chapter VI d i s c u s s e s d a t a of d i s s o l v e d and suspended p a r t i c u l a t e t r a c e m e t a l s i n t h e e s t u a r i n e p o r t i o n o f t h e F r a s e r R i v e r . P o s s i b l e i m p o r t a n c e o f p r o c e s s e s o b s e r v e d i n the F r a s e r e s t u a r y and d e l t a - f r o n t t o o t h e r r e g i o n s and t o the o v e r a l l r e t e n t i o n o f m e t a l s i n n e a r s h o r e zones i s d i s c u s s e d i n Chapter V I I . A b r i e f summary of c o n c l u s i o n s and some recommendations f o r f u r t h e r r e s e a r c h f o l l o w i n Ch a p t e r V I I I . 6 CHAPTER II : DESCRIPTION OF STUDY AREA Introduction The Fraser River , with a length of 1370km and a dra in- age basin area of 234,OOOsq,km, i s B r i t i s h Columbia's largest r i v e r (F ig . 1). Over most of i t s length the r i v e r flows through rugged t e r r a i n composed of vo lcan ic , p lutonic and sedimentary rocks, and g l a c i a l deposits (Garrison e_t aJ, 1969). The las t 130km, the broad lower Fraser v a l l e y , i s underla in by unconsol- idated Pleis tocene and Recent sediments of g l a c i a l , a l l u v i a l , l i t t o r a l and d e l t a i c o r i g i n (Armstrong, 1956). At New Westminster, 24km above the mouth, the Fraser passes through a gap i n topographical ly high Pleis tocene depos- i t s into the region of i t s modern de l ta (Johnston,1921) (F ig . . 2 ) . The modern (or Recent) de l ta represents a per iod of deposit ion during which r e l a t i v e leve l s of sea and land have remained nearly constant, estimated independently as 8000 years (Johnston, 1921) and between 7,300 and 11,000 years (Mathews and Shepard, 1962). The de l ta i s composed of a l l u v i a l and marine deposits and peat, and includes present and former d i s t r ibu ta ry channels, channel bars , f loodpla ins , marshes, t i d a l f l a t s and fore-slope ( F i g . 2) . The seaward-facing perimeter i s 48km and includes the act ive (western) de l ta- f ront which extends from Point Grey to the Point Roberts peninsula (a former i s l a n d ) , and the inac t ive (southern) del ta- front within Boundary Bay. The act ive de l t a - f ront , subject of th i s study, i s prograding westward into Georgia S t r a i t . Topset sediments cover the t i d a l f l a t and sa l t marsh 7 Figure 1: B r i t i s h Columbia and lower Fraser v a l l e y (inset), showing the Fraser River and major t r i b u t a r i e s and d i s t r i b u - t a r i e s . 1 North 1PT ««Y IP Arm^j^ \ THE FRASER RIVER DELTA WITH GENERALISED SURFICIAL GEOLOGY s 4-"' 1 *%>-.....> / -—-' ROBERTS* ' v. LEGEND RECENT | Ri | peot ± silt cover | R* | silt and clay [ R31 sand | R 4 | salt marsh | R 8 | other PLEISTOCENE | P | sandy to silty till, sands, gravels, silt, clay and peat TERTIARY | T | bedrock •—" dykes lowest normal tide geologic boundary sewage outfall channel (from Hoos a Packman 1974, Fig. 3.1 ) FI6. 2 9 zones, which slope only very gradually ( 0 . 0 4 ° or .7m i n 1km) over a distance of 7km. Two i n t e r t i d a l banks, Sturgeon and Roberts Banks, l i e , r e spec t ive ly , north and south of the main channel (F ig . 2) . Foreset beds cover the remaining width of Georgia S t r a i t west of the f i r s t break i n slope (Mathews and Shepard, 1962). Steepness of the fore-slope var ie s , although i t i s everywhere steeper than the t i d a l f l a t s . Inc l ina t ions averaging 1 3/4 to 3 1 / 2 ° occur adjacent to the mouth of the r i v e r (Mathews and Shepard, 1962) and l o c a l values of 1 2 ° (Luternauer and Murray, 1973) and 1 0 ° (Johnston; 1921) have been documented. Hydrology The Fraser River , near i t s mouth, has a mean da i ly flow of 3400m3/sec (Hoos and Packman, 1974). Nearly 80% of the annual t o t a l i s discharged during the freshet months of May through July 3 ( F i g . 3), and the monthly mean for June i s 7075m /sec. Winter discharges, on the other hand, are much lower. March for instance 3 has a mean discharge of 790m /sec. Maximum d a i l y discharges dur- 3 ing the freshet have occurred in excess of 15,000m /sec, and account for per iod ic f looding over the a l l u v i a l p l a i n of the de l ta . The banks of d i s t r ibu ta ry channels are dyked to prevent f looding of populated regions. The r i v e r enters Georgia S t r a i t through four main d i s t - r ibutary channels ( F i g . 2) , the approximate proportion of d i sch- arge ca r r i ed by each being: main channel, 80-85%; Middle Arm, 5%; F i g u r e 3: D i s c h a r g e h y d r o g r a p h f o r 1970, F r a s e r R i v e r a t Hope (Hoos and Pack- man, 1974) 11 North Arm, 5%; and Canoe Pass, 5-10% (Pret ious , i n Luternauer and Murray, 1973). Oceanography The phys ica l oceanography of Georgia S t r a i t has been summarized by Hoos and Packman (1974), Waldichuk (1957), and Thomson (1974a,1975). Most of the fol lowing information i s drawn from these sources. Tides Tides i n Georgia S t r a i t are a mixture of d iurna l and semi-diurnal types, with a marked d iurnal i n e q u a l i t y . In other words,two unequal high t ides and two unequal low t ides occur d a i l y , and times between successive equivalent states of t ide vary. Average t i d a l range in Georgia S t r a i t i s 3m, and range of spring t ides averages 4.6m. T i d a l heights are defined r e l a t i v e to zero chart datum (lowest normal t ide) and are affected by r i v e r discharge only near the mouth of the main channel (Ages and Woollard, 1976). Highest normal t ides cover the ent i re act ive de l ta- front , with waters lapping against dykes along shorel ines of Richmond and Delta (F ig . 2) . At lowest normal t ide water reced- es 6 to 7km, within 1km of the f i r s t d i s t i n c t break in, s lope. Water leve l s i n the lower Fraser River are inf luenced by t ide s i amount and extent of t h e i r influence being determined by t i d a l state and r i v e r discharge (Ages' and Woollard,!. 1976) . v During low flow periods , t i d a l influences are f e l t up to 72km 12 upstream. New Westminster (24km upstream) has a maximum t i d a l range of nearly lm. During the peak freshet flows, however, t i d a l e f fects extend only a short distance upstream of Steveston, being overpowered by the r i v e r flow. T i d a l extremes are prog- re s s ive ly delayed moving upr iver , by amounts not general ly affected by discharge (Ages and Woollard, 1976). Model pred- i c t i o n s of t i d a l delay (Ages and Woollard, 1976) suggest low :. t ides are delayed one hour and two hours at Deas Is land and New Westminster re spec t ive ly , and high t ides are delayed twenty minutes and one hour. Surface Currents Surface currents i n Georgia S t r a i t near the de l ta- f ront are inf luenced pr imar i ly by t ides and Fraser River discharge. T i d a l currents in general ebb to the southeast and f lood to the northwest, the f lood t ide being the stronger. However, drogue studies near the mouth of the Fraser (Giovanda and Tabata, 1970) indicate that actual flows are to.the 'southwestJduring the ebb, swinging to due north on the f lood . The southwestward ebb flow i s i n part due to the force of Fraser River water entering the s t r a i t , and to C o r i o l i s ef fects act ing on brackish surface water. The northerly f lood i s due to C o r i o l i s e f fect s , although near the r i v e r mouth the r i v e r dominates, producing a short southwestward- directed flow. Adjacent to Sturgeon Bank a northward-directed surface current flows at a l l states of t i d e . This current i s be l ieved to be caused by i n t e r n a l waves breaking at shallow depth near the edge of the t i d a l f l a t s (Thomson, 1974b) . Currents near 13 the mouth of the North Arm are northwestward, veering around' Point Grey and into Burrard Inlet on the f lood. Currents over the i n t e r t i d a l banks of the de l t a are produced by f looding and ebbing t ides and are roughly at r i gh t angles to the shore. The f lood t ide i s the stronger and there- fore shoreward currents are more powerful than seaward currents . Surface current magnitude and d i r e c t i o n at the r i v e r mouth and in d i s t r i b u t a r y channels are dependent on r i v e r flow and state of t i d e . Downstream v e l o c i t i e s i n the main channel are normally 3 to 4 knots during ebb t i d e , but may reach 5.5 knots during the freshet (Tabata, 1972). On f looding t ides surface speeds are considerably reduced, and actua l ly reverse at most times of the year, often as far upstream as New Westmins- te r . Interact ion of Fraser River and Georgia S t r a i t Waters Sediment-laden r i v e r water, because of i t s lower density, spreads over the surface of Georgia S t r a i t i n a turb id plume, where i t s movement i s determined by factors which contro l surface currents . Mixing between fresh and sa l ine waters occurs only at t h e i r in ter face , with a loss of s a l ine water to over ly ing r i v e r water. A two-layered estuarine system thus develops with over ly- ing brackish water outflow and sa l ine subsurface inflow (Wald- ichuk, 1957). The r e l a t i v e l y t r a n q u i l waters of centra l Georgia S t r a i t allow the two-layered system to p e r s i s t . A two-layered system exi s t s also in the main channel of the Fraser due to a wedge-shaped in t rus ion of sa l ine water along the base of the channel. Penetration distance i s dependent 14 on discharge, state of t i d e , and dif ference between successive t i d a l heights . During the winter penetrations greater than 15km have been recorded (Hodgins, 1974), while during the freshet the sa l ine wedge probably never passes Steveston (Pret- ious, 1972). On the large ebb of every t i d a l cycle the sa l ine water i s completely flushed out of the main channel (Hodgins, 1974). The ha loc l ine associated with the s a l t wedge i s not as we l l defined as that in wel l s t r a t i f i e d es tuar ies : a ce r t a in amount of two-way mixing between layers occurs, along with up- stream convection of brackish Georgia S t r a i t surface water on f looding t ides (Hodgins, 1974). Penetrat ion of the sa l ine wedge general ly lags two or three hours behind a r r i v a l of high t ide (Hodgins, 1974). Consequently v e l o c i t y gradients are common within the channel, and, i n extreme cases, surface and bottom waters flow i n opposite d i r e c t i o n s . Sedimentology Sediment Transport i n the Fraser River 7 3 The Fraser transports an average of 1.98 x 10 m of sediment to the de l ta- f ront each year (Mathews and Shepard, 1962). A l l mater ia l destined to reach the del ta- front i s probably i n suspension at Hope (Mathews and Shepard, 1962), but a large proport ion of the annual load has s e t t l e d out upstream of Steveston (Mi l l iman, i n press ) . Mater ia l s e t t l i n g out of suspension i s mainly sand, as evidenced by the small proport ion of s i l t and clay in r i v e r bottom sediments upstream of Steveston (Tywoniuk, 1972). Bed-load sands in the t i d a l l y affected port ion of the r i v e r are subject to resuspension during ebb t ide ( M i l l i - man, i n press ) . This ef fect i s p a r t i c u l a r l y noticeable i n the lowermost reaches of the r i v e r where resuspension of sand causes a t u r b i d i t y maximum. S i l t and clay content of the water column, in contrast , i s r e l a t i v e l y constant with respect to p o s i t i o n , t ide and depth i n the lower reaches of the r i v e r , ^although on some occasions a s l i g h t increase i n suspended s i l t and clay may r e f l e c t resuspension (Mil l iman, i n press ) . A t u r b i d i t y maximum of continuously suspended s i l t - p l u s - c l a y has not been demonstrated, although the two-layer flow system (p. "••14) might produce such a maximum near the toe of the s a l t wedge, as observed i n other s t r a t i f i e d estuaries ( e . g., Schubel, 1968). Quartz, fe ldspar , c h l o r i t e s and micas were i d e n t i f i e d by x-ray d i f f r a c t i o n of suspended sediments c o l l e c t e d during t h i s study. V i s u a l analys i s of f i l t e r s i d e n t i f i e d large quartz and b i o t i t e grains . Sediment D i s t r i b u t i o n on the Act ive Delta-Front Luternauer and Murray (1973) have described sediment- ary environments wi th in the study area. The s a l t marsh (F ig . 2) i s a lkm-wide f l a t to hummocky region of f ine sediment l y i n g near high t ide l e v e l (Luternauer and Murray, 1973). It i s character ized by a dense s a l t - t o l e r - ant vegetation cover during spring and summer. Sediments, where undisturbed, show d i s t i n c t a l te rnat ing laminations of f ine sand and mud (Plate 1) on a scale of f i ve pairs per cm (Johnston, 1922). Very l i k e l y , f ine sand laminations represent mater ia l set 1 6 Plate 1: Upper port ion of Cores 34, 38 and 16 ( l e f t to r ight) co l l ec ted from three contras t ing environments on Roberts Bank. Metal contents of cores are displayed i n F i g . 17. l i n g on the strong f looding t ide s , while muddy laminations are deposited at s lack water. Unfortunately annual or seasonal sedimentation rates are not ava i lab le to test th i s theory. T i d a l f l a t s extend seaward from the marsh to the l i n e of lowest normal water l e v e l (F ig . 2). They are covered by f ine sand and s i l t , and, e spec ia l ly adjacent to Middle Arm and Canoe Pass and near low t ide l i n e , by medium grained sand (Luternauer and Murray, 1973). T i d a l f l a t s are featureless except for sha- llow t i d a l channels and hydraul ic bedforms (Medley and Luternauer, 1976). Sediment cores lack d i s t i n c t i v e layer ing (Plate ~1), *> because constant current , wave, channeling and burrowing act ion tends to destroy t h e i r s t ra t igraphy. A facies succession of s a l t marsh muds over t i d a l f l a t sand i s t y p i c a l i n regions where the s a l t marsh i s advancing (see- Plate 1:.).'. F luctuat ion of environmental condit ions from year to year leads to a l t e rna t ing mud and sand i n t e r l a y e r s . Sediments of the upper fore-slope of Sturgeon Bank are considerably f i n e r than t i d a l f l a t sediments (F ig . 2) and decrease in s ize to the west. The same i s true west of the northern port ion of Roberts Bank. To the south, however, the fore-slope i s mantled with sand wel l into deep water.(Luternauer and Murray, 1973). It appears that northward-trending i n t e r n a l wave-generated currents and f lood t i d a l currents (p. 12) move the plume north from the main c h a n n e l , r e s t r i c t i n g supply of suspended sediment to the Roberts Bank fore-s lope. A l t e r n a t e l y , subsurface currents of unknown nature may prevent deposit ion of sediment i n th i s region, and may contribute to the erosion and retreat of t h i s part of the de l ta- f ront (Mathews and Shepard, 1962; Lutern- 18 auer and Murray, 1973; Luternauer, 1975a). The clay content of sediments of the study area i s general ly low, reaching an average maximum of 30 to 40% i n s ta t ions furthest offshore from the Sturgeon Bank fore-slope (Luternauer, unpublished data). Muddy s a l t marsh samples from Roberts Bank contain over 20% c lay , but other s a l t marsh and t i d a l f l a t sediments contain l i t t l e or no c lay . Much of the c l ay- s i ze mater ia l , however, may be f i n e l y ground rock-forming p h y l l o s i l i c a t e s rather than pedogenically formed minerals . Pharo (1972), for example, has in fe r red that c l ay- s i ze ' i l l i t e ' i n Georgia S t r a i t i s f i n e l y ground mica. Mineralogy of some delta-front sediments was i n v e s t i g - ated by MacKintosh and Gardner (1966). S i l t f ract ions were found to contain quartz, fe ldspars , micas, c h l o r i t e s , amphibbles and pyroxenes, with non-phy l lo s i l i c a t e s more prominent i n the coarse subtract ion . Clay f ract ions contain montmorillonoid minerals , c h l o r i t e s and micas, with mixed-layer chlori te-mont- m o r i l l o n i t e , quartz and feldspars i n the coarse subtrac t ion . The s i l t f r a c t i o n of Georgia S t r a i t sediments was found by Pharo (1972) to contain micas, quartz, c h l o r i t e s , feldspars and amphiboles. A l l these minerals plus montmoril lonite are found i n the clay f r a c t i o n , the l a s t mineral being dominant i n the f ines t subtract ion . Minerals of the s i l t - p l u s - c l a y f r a c t i o n of samples analysed i n th i s study include quartz , fe ldspars , c h l o r i t e s and micas, and minor amphiboles. 19 Average composition of de l ta- f ront sands was reported as 40% quartz, quartz i te and chert , 11% feldspars , 45% unstable rock fragments (mainly volcanics) and 4% m i s c e l l - aneous de t r i tus (Garrison et a l , 1969). However, v i s u a l inspect ion of sands c o l l e c t e d in th i s study shows that amphiboles, epidote, c h l o r i t e s , micas and magnetite are common const i tuents . Environmental Considerations Environmental knowledge of the ent i re Fraser River de l ta and estuary has been summarized by Hoos and Packman (1974). This work should be consulted i n regard to ecosystems and environmental problems of the de l t a - f ront . As do most estuarine areas, the Fraser de l ta- f ront hosts an extremely complex and p r o l i f i c b i o t a . The proximity of major urban and i n d u s t r i a l centres such as Vancouver and New Westminster renders the region suscept ible to environmental contamination, and consequent introduct ion of fo re igh substances to ecosystems and food chains. The lower leve l s of the food chains include plants and minute crustaceans, with f i s h , b i rds and man occupying the upper t rophic l e v e l s . Of p a r t i c u l a r concern i s a m u l t i - m i l l i o n d o l l a r f i s h e r i e s industry , whose curtailment would d r a s t i c a l l y affect reg ional economy. Trace metals are waste products of many l o c a l a c t i v i t i e s , inc lud ing petroleum use and chemical indus t r i e s , and are known to occur i n lower Fraser River water and sediment i n higher than normal concentrations ( H a l l and F le t cher , 1974; H a l l et a l , 1974). Lead and z inc concentrations in u n f i l t e r e d waters from the v i c i n i t i e s of New Westminster and Annacis Island have been recorded i n excess of 30 and 70ug/l respect- i v e l y (Ha l l et a l , 1974). The Greater Vancouver Regional D i s t - r i c t primary sewage treatment plant at Iona Is land (F ig . 2) i s supplying a further input of metals to the de l t a - f ront . Waste received by t h i s plant contains median Cu, Pb and Zn concentrations of 105, 39 and 108ug/l respect ive ly ( H a l l et a l , 1975). Metal associated with sediment enters food chains through f i l t e r - f e e d i n g and sediment-ingesting organisms, and marsh vegetation. Crabs and molluscs from Sturgeon Bank, for example, contain greater concentrations of several metals than those from Roberts Bank (Parsons et a l , 1973), probably as a re su l t of ef f luent discharged from Iona Is land. Copper concentrations, for example, range from. 38 - 150ppm i n animals from Sturgeon Bank, and from 22-68ppm i n animals from Roberts Bank (Parsons et a l , 1973). 21 CHAPTER I I I : SAMPLING AND ANALYTICAL PROCEDURES Sample C o l l e c t i o n Sediments The s u r f i c i a l sediment sampling programme, planned and supervised by Dr. J . L . Luternauer of the Geologica l Survey of Canada, was designed to provide a monthly record of the di sp- er sa l of sediments over the act ive de l ta- f ront before, during and after the freshet of 1974 (Luternauer, 1975b). T i d a l f l a t s were sampled during February, A p r i l , May, June and October. Upper fore- slope sediments were c o l l e c t e d i n March and October, for a t o t a l of 691 samples. Locations of'samples c o l l e c t e d i n February and' March, 1974 are shown i n F i g . 4. T i d a l f l a t s were sampled at lowest t ides from the Coast Guard Hovercraft s tat ioned at Sea Is land. A regular g r id of 70 s tat ions was planned, but could not be r i g i d l y adhered to , as access ible topographic highs s h i f t constantly across the sand f l a t s . Locations were determined to wi th in 30m using the c r a f t ' s Decca radar system. Sediments were c o l l e c t e d using a glass 1 p e t r i dish to make a 10cm by 1cm disc of sediment. The sediment was s l i d onto a r i g i d v i n y l sheet and placed in high wet strength kraf t bags. Upper fore-slope sediments were sampled from a Depart- ment of Transport launch along east-west transects using a Shipek sampler with a s t a in le s s s t e e l bucket. Only the upper few c e n t i - metres of the grab were placed i n sample bags. Locations were determined to wi th in 10m using a Trisponder navigat ional system. Sediment cores were c o l l e c t e d from exposed parts of 22 F i g u r e 4: L o c a t i o n s o f s u r f i c i a l sediment samples (Fe b r u a r y and March sam p l i n g s e r i e s ) , F r a s e r d e l t a - f r o n t i n t e r t i d a l and f o r e - s l o p e r e g i o n s ( o r i g i n o f c o o r d i n a t e s a t 49°00'N, 123°25'W). 23 the t i d a l f l a t s during the summer of 1975 ( F i g . 5) . Dykes and causeways provided access to several l o c a l i t i e s . Other s tat ions were reached by Canova boat v i a r i v e r and t i d a l channels. Cores were extracted far enough away from man-made b a r r i e r s to be un- affected by mater ia l washed out of f i l l . Cores of roughly 70 to 80cm length were extracted by pounding a 6cm i . d . PVC core l i n e r into the sediment. A PVC pis ton ( F i g . 6) was held at the same l e v e l as the l i n e r was intruded, to prevent compaction. A rubber d i sc near the top of the p i s ton act- ed as an a i r sea l , thus maintaining a vacuum wi th in the l i n e r and allowing successful extract ion of the sediment. Cores were capped and transported v e r t i c a l l y back to the laboratory where the l i n e r was cut length-wise with a c i r c u l a r saw. A s t a in le s s s t e e l spat- ula was inserted through the s p l i t l i n e r and drawn through the core. One ha l f of the core was then div ided into 5cm subsamples after the top 1cm and a few mil l imeters of the outside surface had been discarded. Subsamples were placed i n kraf t bags, while the other ha l f of the core was saved for descr ip t ion and photogr- aphy. Waters On August 19, 20 and 21, 1975 water samples were c o l l e c - ted from lm depth at eight s ta t ions on the Fraser River from the UBC Geologica l Sciences Department motorboat Naut i lus . Samples were c o l l e c t e d with the boat facing upstream using a van Dorn sampler. At each s ta t ion water was poured into two 21 polyprop- ylene asp ira tor bot t le s which had- been previous ly washed with 50% F i g u r e 5: L o c a t i o n s of i n t e r t i d a l sediment s h o r t core samples. F i g u r e 6: Diagram of sediment coring device used i n t h i s study. 26 HC1 and rinsed with d i s t i l l e d water. Water conductivity was measured in s i t u with a Hydrolab probe conductivity meter. At stations 3, 4 and 5 steep s a l i n i t y gradients were detected with increasing depth. Additional water samples were taken at these locations at a depth of r e l a t i v e l y constant s a l i n i t y , apparently within the zone of s a l t water intrusion. Samples were taken immediately back to the laboratory for f i l t r a t i o n . Sample Preparation Sediments Surface samples and core subsamples in kraft bags were a i r - d r i e d at 70°C for at least 48 hours. Dried material was disaggregated with a ceramic mortar and pestle. Portions of each sample were then passed through a nylon sieve to produce fractions coarser and f i n e r than 80-mesh or 177um (plus80 and minus80-mesh). Sieved material was placed i n coin envelopes and the remainder of the sample l e f t i n the kraf t bags. Waters and Suspended Sediments On returning to the laboratory water in aspirator bott- les was f i l t e r e d under Ng pressure through preweighed .45um Sart- orius membrane-filters. The f i r s t 100ml of f i l t r a t e was discarded, after which acid-washed 11 polybottles were used to c o l l e c t f i l t - rate. One-litre bottles were rinsed with a small amount of f i l t - rate before f i l l i n g them. D i s t i l l e d - d e i o n i z e d water was passed through the f i l t e r s when f i l t r a t i o n was complete. Two f i l t e r s 27 were used per sample, one for each 2.1 aspirator b o t t l e . F i l t e r e d waters were a c i d i f i e d with 5ml concentrated HG1 and stored at 4 ° C . F i l t e r s were placed i n separate dust-free p l a s t i c dishes i n a dess icator and allowed to dry at room temperature before reweighing to estimate weight of p a r t i c u l a t e s . To test for f i l t e r weight changes during f i l t r a t i o n 21 of d i s t i l l e d water was forced through each of eight pre-weighed f i l t e r s , four of which were allowed to dry i n a dess icator , four i n a drawer. S i g n i f i c a n t weight loss (3mg) occurred in only one case. No correc t ion was made therefore for changes i n f i l t e r weight. Trace Metal Analyses Sediments Metal extract ion Several extract ion procedures were used to l i b e r a t e d i f fe rent forms of trace metals from sediments. Perusal of the l i t e r a t u r e suggested many alternate combinations of reagents to i so l a te various chemical f r a c t i o n s . MgClg was chosen to separate adsorbed metals rather than ammonium acetate, the usual cat ion exchange determinant, because ammonium acetate has been found to d i s so lve i ron oxide grain coatings (Gibbs, 1973). Moreover M g + + i s a major ion i n the marine environment, making the experiment somewhat c loser to r ea l condi t ions . Whether th i s re- agent releases a l l adsorbed metal, or only that i n cat ion exchange p o s i t i o n , i s unknown. 1M NH20H.HC1 i n 25% ace t i c ac id (HHA) was se lected as the most su i tab le reagent to separate metals associated with amor- 28 phous i ron and manganese oxides (Chester and Hughes, 1973). High rate of recovery with minimum destruct ion of c lay mineral l a t t i c e s and c r y s t a l l i n e i ron oxides have been reported with th i s reagent. Combined ac id attacks (HN0 3-HC10 4 and HF-HN0 3-HC10 4) are known to l ibe ra te the bulk of metals bound i n c r y s t a l l i n e min- era l s , y i e l d i n g near- tota l metal contents when used without pre- ceding extrat ions . Experimental procedures are out l ined below. D i g e s t i o n wi th HNO^-HCIO^ This was the routine procedure used to l ibera te the bulk of la t t ice-bound metals and obtain near-ntotal metal contents of sediments. A 2ml a l iquot of 4:1 HNOg-HClO^ was added to 0.500g of dr ied sediment, and evaporated to dryness on a hot-air . bath. The residue was dissolved in warm 6M HC1 and the so lu t ion d i l u t e d to 1.5M for ana lys i s . Necessary d i l u t i o n s were made using 1.5M HC1. Sequential treatment with 1M MgClg , HHA and HN03-HC1C>4 •* To f i r s t remove adsorbed metals 2.500g of dry sediment was leached by shak- ing for four hours with 20ml 1M MgClg. The so lu t ion was then centrifuged and the supernatant so lu t ion analysed. After washing with d i s t i l l e d water the residue was shaken for four hours with 20ml HHA to remove amorphous oxides and hydrous oxides of i ron and manganese, together with associated trace metals. One-half gram of the residue was then digested i n HNOg-HC104 as described above. Sequential treatment with HHA ..and HF-HN0 3-HC10 4 : Minus80-mesh sediments were s p l i t into sand (plus270-mesh) and s i l t - p l u s - c l a y (minus270-mesh) f ract ions using a nylon s ieve . 4.000g of each 29 f r a c t i o n was shaken for four hours with 40ml HHA to remove adsorbed and hydrous oxide-associated metals. The suspension was c e n t r i f - uged and the supernatant so lu t ion was saved for ana lys i s . The residues were washed with d i s t i l l e d water, and the sand f r ac t ion s p l i t into heavy and l i g h t f ract ions using bromoform (S.G.=2.89) i n a separatory funnel . 0.200g of the heavy- sand f r ac t ion and 0.500g of the l i g h t sand and s i l t - p l u s - c l a y f ract ions were digested in te f lon dishes with 5ml HF and 2ml 4:1 HN0 3-HC10 4 . Af ter eva- porat ion to dryness on a hot p l a te , the residue was taken up i n 6M HCl and then d i l u t e d to 1.5M with d i s t i l l e d water. Atomic absorption spectrophotometry For analys is of above solut ions i t was necessary to prepare standard so lut ions i n 1.5M HCl , 1M MgCl 2 or HHA as appropriate. Solutions were analysed on e i ther a Varian Techtron TV or Perkin-Elmer 303 atomic absorption spectrophotometer, using an a i r-acetylene flame under condit ions l i s t e d i n Table I. Corr- ect ions for background absorption were made for Co, Ni and Pb using a continuum l i g h t source (F le tcher , 1970). One set of dupl icates , a standard sample and a reagent blank were included in every batch of 24 samples during HN0 3-HC10 4 procedure. P r e c i s i o n , based on dupl icate sample ana lys i s , i s tabulated i n Table I I . P rec i s ion of sequential ex t rac t ion analy- ses, based on dupl icate samples, i s given i n Table I I I . General ly poor prec i s ion for Pb r e f l e c t s the high proportion of values app- roaching or below the detection l i m i t of the methods. Suspended Sediments After drying , one of the two f i l t e r s used per sample was O . • • Element Flame Wavelength(A) Current(mA) S l i t ( u m ) Background C o r r e c t i o n Co A i r - a c e t y l e n e 2407 1 8 a 300 a yes Cu „ 3248 1 4 ( 3 ) b 1000(50) b Fe 3719 20(5) 300(50) Mr. M 2795 15(5) 1000(50) Ni "• 2320 16 300 yes Pb 2170 14 1000 yes Zn 2139 14(6) 3000(100) a Perkin-Elmer 303 b V a r i a n Techtron IV Table I n s t r u m e n t a l c o n d i t i o n s of atomic a b s o r p t i o n spectrophotometry. to o 31 Element Precisi o n ~% ( 9 5 % confidence) Co 10.3% Cu 8.4 Fe 6.4 Mn IS.9 Ni 5.6 Pb 45.7 Zn 9.3 Table II: A n a l y t i c a l precision of HNO^-HCIO^ attack, based on analysis of 20 paired samples. Precision -% ( 9 5 % confidence) Element HHA-extraction HNOg-HClO^-extraction Co * 62.8 Cu 4.2 8.2 Fe 19.9 5.3 Mn 6.6 4.1 Ni 17.8 17.8 Pb 8.5 82.6 Zn 20.8 6.9 * not calculated. Table I I I : A n a l y t i c a l precision of f i r s t sequential extraction experiment, based on analysis of 6 paired samples. 32 placed i n a Teflon dish with 4ml 4:1 HNO3~HC104 and 2ml HF and heated on a hot plate u n t i l dry. The residue was taken up in 6ml 6M HC1, and the so lu t ion poured in to an acid-washed 25ml volum- e t r i c f lask and taken to volume with d i s t i l l e d water. A 5ml a l iquot of th i s so lu t ion was d i l u t e d 200 times with 1.5M HC1 for analys i s of Fe, Ca, Mg, Na and E . D i lu ted so lut ions contained 10ml .07M CsCl and .37M LaO so lut ions per 100ml to suppress interferences i n determinations of Na and K, and Ca and Mg resp- e c t i v e l y . The remainder of the 25ml was analysed d i r e c t l y for Cu, Mn and Zn by atomic absorption. The other f i l t e r from each sample was placed i n an ac id- washed 150ml beaker and immersed i n 5ml HHA to remove adsorbed and hydrous oxide-associated metal. Beakers were agitated gently for four hours on a gyrating surface, and the l i q u i d was poured into a 10ml volumetric f lask and taken up to volume with HHA. Solutions were analysed d i r e c t l y for Fe, Mn and Zn by atomic ab- sorpt ion . HHA-leached f i l t e r s were washed with d i s t i l l e d water and allowed to dry at room temperature for use in x-ray d i f f r a c t - ometry. Waters Dissolved Cu, Zn and Fe i n f i l t e r e d waters were analysed i n the Water Quality Lab at B .C . Research using a che la t ion- solvent extract ion method. 750ml of a c i d i f i e d f i l t e r e d waters were adjusted to pH2.5 with r e d i s t i l l e d HG1. 30ml of a 1% (w/v) so lu t ion of the complexing agent ammonium p y r r o l i d i n e dithiocarbamate (APDC) in deionized water was placed, along with the sample, in a 33 separatory funnel and shaken. Af ter standing for 10 minutes the APDC was extracted and removed three times i n t o , success ive ly , 20ml, 10ml and 10ml of chloroform. Chloroform extracts were evaporated to dryness, and the residues digested in 5ml of concentrated HNOg. After warming u n t i l brown fumes were no longer evolved, 10ml of deionized water was added and b o i l e d u n t i l a c lear so lu t ion was obtained. Solutions were made up to 25ml i n a volumetric f l a sk . Analyses were done by atomic absorption, using standards made from a mixture of extracted water samples (reextracted once more with 10ml chloroform) by spiking with mixed standards and extract ing as above. Minera log ica l Determinations S u r f i c i a l Sediments Mater i a l f i n e r than 270-mesh, previous ly treated with HHA and assumed to be e f f e c t i v e l y NH*-saturated, was made into a s l u r r y with d i s t i l l e d water and placed on a glass s l i d e for x- ray d i f f r a c t i o n . Subsequent to the f i r s t scan ( 3 - 2 5 ° 26) samples were treated with two drops of ethylene g l y c o l , and were allowed to dry at room temperature for one hour. After a second scan ( 3 - 1 4 ° 26) samples were heated at 3 0 0 ° C for one hour i n a muffle furnace and rescanned. A P h i l i p s x-ray di f fractometer , u t i l i z i n g CuKa rad ia t ion at a p o t e n t i a l and current of 40kv and 20ma, was employed. Mineral i d e n t i f i c a t i o n s were made by r e f e r r a l to C a r r o l l (1970, F i g . 11 and Table 9) and Chao (1969). Qual i ta t ive v i s u a l i d e n t i f i c a t i o n of sand-size mater ia l 34 was done under the binocular microscope. Suspended Sediments Small port ions of HHA-leached f i l t e r s were cut with sc i s sor s and mounted d i r e c t l y on glass s l ide s with Scotch tape. X-ray d i f f r a c t i o n was ca r r i ed out as described for s u r f i c i a l s ed i - ments. To heat, f i l t e r s were placed i n c r u c i b l e s , and the r e s u l t - ing sediment f lakes were disaggregated with mortar and pes t le . Mater i a l was then spr inkled onto glass s l ide s which were coated with a th in layer of s i l i c o n e stop-cock grease. Grain Size Determinations Weight percent of sand i n the f i n e r than 80-mesh f r a c t - ion (%sand) of February and March surface samples and se lected cores was determined by wet-sieving approximately l g of sediment through a 270-mesh (53um) nylon s ieve, then drying and weighing the f r a c t i o n reta ined. Loss on Ign i t ion Organic content of the f iner than 80-mesh f r ac t ion was estimated as percent weight loss on i g n i t i o n (%LI) after heating l.OOOg of sediment for four hours at 5 5 0 ° C i n a muffle furnace. LI values have been shown to be proport ional to organic carbon content i n other environments (Coker and N i c h o l , 1975). Carbonate minerals are not destroyed at t h i s i g n i t i o n temperature (Timperley and A l l a n , 1974). 35 Corre l a t ion and Regression Analys i s Corre la t ion matrices and regression equations were computed using the UBC TRIP computer program (B jer r ing and Sea- graves, 1974). S igni f icance of cor re l a t ion coe f f i c i en t s at the 95% confidence l e v e l was determined from Table VIII of Sokal and Rohlf (1973). The stepwise mul t ip le regression produces equations of the form Y = b „ + b .x . + b n x n + . . . + b x 0 1 1 2 2 n n where Y i s a dependent var i ab le , x ^ X 2 , . . . x n are independent var iab le s , and b Q , b ^ , . . . b are regression c o e f f i c i e n t s . Independ- ent var iables making a s i g n i f i c a n t contr ibut ion at the 95% conf id- ence l e v e l are reta ined i n equations, and those making no s i g n i f - 2 icant contr ibut ion are e l iminated. Values of r , the proportion of v a r i a b i l i t y in the dependent var iab le accounted for by the independent var iab les , are produced. Residuals , the di f ferences between values observed and those predicted by regression equations, are l i s t e d i n actual and normalized form. 3 6 CHAPTER IV: TRACE METALS IN SURFICIAL SEDIMENTS OF THE FRASER RIVER DELTA-FRONT Introduction S u r f i c i a l samples from i n t e r t i d a l and upper fore- slope regions of the Fraser River ac t ive de l ta- f ront were analy- sed for t o t a l contents of Co, Cu, Fe, Mn, N i , Pb and Zn. S i g n i - f icant s t a t i s t i c a l corre la t ions between metals and sediment texture suggested chemical and phys ica l p a r t i t i o n i n g experiments useful to e luc idate metal forms and associat ions in sediment. Results Trace Metal Content and D i s t r i b u t i o n Results of t o t a l Co, Cu, Fe, Mn, N i , Pb and Zn analyses on minus80-mesh mater ia l are l i s t e d i n Appendix A, and means and standard deviations for each sampling ser ies are l i s t e d in Table IV. Mean values of metals i n t i d a l f l a t samples do not d i f f e r s i g n i f i c a n t l y between sampling se r i e s . The February ser ies samples are therefore taken to be repres- entat ive of i n t e r t i d a l sediments, and most of the ensuing descr ip t ion i s based on samples from that ser ies together with the March ser ies of fore-slope samples. In general mean values of the metals studied here are higher i n fore-slope samples than i n i n t e r t i d a l samples (Table IV). This tendency applies to contents of Fe (15% higher ) , Zn Metal Content (ppm) Sampling Series Co Cu Fe(%) Mn Ni Pb a Zn %sand %LI Intertidal A February 11. ,3b 17. .2 1, .86 310 43. .5 5. 8 52, .8 81, .6 1. .8 (n=68) 1, ,6C 7. .7 0, .27 56 7. .8 9. 1 11. .0 21, .6 1, .0 C April 13. .3 17, .5 1. .93 357 47, .5 5. 2 55, .7 (n=69) 1. ,9 10, .1 0, .33 75 12. . 1 5. 5 14, .9 D May 14. . 1 20, .4 2. ,09 390 47, .7 6 . 1 58, .0 (n=70) 2. .6 12. .0 0, .41 132 8. .2 6. 2 15, . 3 E June 11. ,6 17. .6 1, .94 336 44, .0 5. 2 53 .0 (n=64) 2. ,0 9. .9 0, .37 105 7. .9 4. 8 13. .6 F October 12. .3 13. .7 1. . 74 337 44. ,0 6. 7 47. .5 (n=46) 2. .5 5 , .8 . .30 245 7, .6 3. 6 8 .4 Fore-slope B March 13. .3 30. .0 2 .34 327 47, .9 10 .7 77, .1 45. .5 3. .5 (n=218) 1. .8 13, .1 0, .47 56 6, .3 7 .8 21, .7 31, .8 2. .0 G November 12. .1 31, .5 2, .46 279 47, .1 14 .2 71, .5 (n=153) 2. ,2 16, .4 0. .44 41 5, .3 10 . 7 24, .6 a Pb values below detection limit excluded b Mean values c Standard deviation Table IV: Metal content, percent sand content and loss on ignition of Fraser delta-front sediments ( a l l data on finer-than 80-mesh material). 38 (45%), Cu (75%) and Pb (85%), but does not apply to Ni and Mn contents. The r e l a t i v e t o t a l metal content of fore-slope and i n t e r t i d a l samples i s apparent i n metal d i s t r i b u t i o n maps (F igs . 7 to 13). It i s also apparent from these maps that i n t e r t i d a l sediment contents of Cu, Fe, Pb and Zn are highest nearest to shore, while the reverse i s true of sediments on the fore-s lope. The fore-slope region displays an even more marked trend i n these elements, and to a lesser extent Co and Mn, whereby t o t a l metal concentrations increase i n a northwesterly d i r e c t i o n from the U.S . border to the mouth of the Main Arm, and then gradually increase northward along the slope of Sturgeon Bank to the v i c - i n i t y of Point Grey. These trends are interrupted only by r e l a t - i v e l y lower metal values i n sediments d i r e c t l y of f the mouth of the main channel and e spec ia l ly the North Arm. Sediments from the northern part of the study area are therefore markedly en- r iched i n , for example, Zn, Cu and Pb (2x, 3 to 4x and lOx higher respect ive ly) compared with those from the southern ext- remity. Trends of metal enrichment are shown by representat ive north-south and east-west transects of Pb and Zn values in samp- les from the fore-slope west of Sturgeon Bank and the North Arm (F ig . 14). This general pattern of t o t a l metal d i s t r i b u t i o n appears to be inverse ly re la ted to sediment grain s i z e , as represented by the d i s t r i b u t i o n of sand i n s u r f i c i a l sediments (F ig . 15). In other words, regions of the del ta- front r i c h i n f ine grained mater ia l , such as nearshore portions of the i n t e r t i d a l zone and the slope west of Sturgeon Bank, are the r i c h e s t ' i n metals, while regions of high sand content, such as the western part of the 39 F i g u r e 7: D i s t r i b u t i o n o f Co i n the minusSO-mesh f r a c t i o n o f F r a s e r d e l t a - f r o n t s u r f i c i a l sediments ( F e b r u a r y and March sampl i n g s e r i e s ) . 40 F i g u r e 8 : D i s t r i b u t i o n of Cu i n the minus80-mesh f r a c t i o n of Fraser de l t a - f ront s u r f i c i a l sediments (February and March sampling s e r i e s ) . 41 Figure 9: D i s t r i b u t i o n of Fe i n the minus8 0-mesh t r a c t i o n or Fraser de l t a - f ront s u r f i c i a l sediments (February and March sampling s e r i e s ) . 42 F i g u r e 10: D i s t r i b u t i o n o f Mn i n the minus80-mesh f r a c t i o n o f F r a s e r d e l t a - f r o n t s u r f i c i a l sediments ( F e b r u a r y and March sampl i n g s e r i e s ) . 43 F i g u r e 11: D i s t r i b u t i o n o f N i i n the minus80-mesh f r a c t i o n o f F r a s e r d e l t a - f r o n t s u r f i c i a l sediments ( F e b r u a r y and March s a m p l i n g s e r i e s ) . 44 Figure 12: D i s t r i b u t i o n of Pb in the minus80-mesh f r a c t i o n of Fraser de l t a - f ront s u r f i c i a l sediments (February and March sampling s e r i e s ) . 45 Figure 13: D i s t r i b u t i o n of Zn i n the minus80-mesh f r a c t i o n of Fraser de l t a - f ront s u r f i c i a l sediments (February and March sampling s e r i e s ) . 46 F i g u r e 14: Pb and Zn c o n t e n t s (ppm) o f s e l e c t e d s u r f i c i a l s e d i - ments from the f o r e - s l o p e west o f S t u r g e o n Bank (March s a m p l i n g s e r i e s ) . 47 F i g u r e 15: D i s t r i b u t i o n o f sand (plus270-mesh) i n t h e minusSO- mesh f r a c t i o n o f F r a s e r d e l t a - f r o n t s u r f i c i a l s e diments ( F e b r u a r y and March s a m p l i n g s e r i e s ) . 48 t i d a l f l a t s and the slope west of Roberts Bank, are the poorest. Moreover, gradual trends of metal enrichment, such as those d i s - played i n F i g . 14, are re la ted to decreases i n sand content (F ig . 15), most not iceably i n the regions west of Sturgeon Bank and the mouth of the North Arm. Two samples c o l l e c t e d d i r e c t l y southwest of Iona Is land contain abnormally high concentrations of Cu (43 and 47ppm), Pb (39 and 29ppm) and Zn (83 and 95ppm) compared to i n t e r t i d a l sediments elsewhere (F igs . 8, 12 and 13). Corre l a t ion and Regression Analys i s S t a t i s t i c a l analysis of t o t a l metal contents of de l t a - front sediments reveals strong pos i t ive corre la t ions between metals with the most we l l defined geographic trends (Cu, Fe, Pb and Zn, and to a lesser extent, Co) and strong negative cor re l a t ions between these metals and sand content (Tables V and V I ) . Mn is highly p o s i t i v e l y corre la ted with the above metals and negatively corre la ted with sand content on the fore-s lope. Ni corre lates with Co, and to a lesser extent with Fe and Mn. Loss on i g n i t i o n data are negatively corre la ted with sand content, and p o s i t i v e l y corre la ted with Zn, Cu, Fe, Pb and Co i n both t i d a l f l a t and fore-slope sediments, and with Mn i n fore-slope sediments. In general corre la t ions are stronger among fore-slope sediment metal contents. Corre la t ion coe f f i c i en t s between Cu, Pb and Zn contents, for example, are a l l above .65 i n t i d a l f l a t samples, and above .85 i n fore-slope samples. Negative c o r r e l a - t ions between metals and sand content are also general ly stronger i n fore-slope samples, as exemplif ied by Fe-sand c o r r e l a t i o n co- Co Cu Fe Mn Nl Pb Zn .49 Fe ,83 .59 Mn .39 .13 .26 Ni .72 .02 .53 .28 Pb .32 . 72 . 38 .00 .00 Zn .62 .88 .70 .10 .10 . 65 %hl .36 .67 .55 - .01 - .18 . 38 .72 %sand - .53 -.81 - .73 - .14 - .03 - .53 -.82 Table V: C o r r e l a t i o n matrix for i n t e r t i d a l sediments c o l l e c t e d in February, 1974 ( f i n e r than 80-mesh mater i a l ; n=68; r=.24 s i g n i f i c a n t at 95% confidence l e v e l ) . Co Cu Fe Mn Ni Pb Zn Cu . 6 9 Fe . 7 8 . 8 5 M E . 6 8 . 7 6 . 8 5 Ni . 5 3 . 1 1 . 3 8 . 4 3 Pb . 5 5 . 8 7 . 6 8 . 6 7 - . 0 1 Zn . 7 0 . 9 3 . 8 9 . 8 2 . 1 9 . 8 5 % L I . 4 5 . 6 8 . 6 6 . 5 9 . 0 8 . 5 2 . 7 0 %sand - . 7 0 - . 9 2 - . 8 7 - . 6 8 - . 0 9 - . 7 6 - . 9 0 Table V I : C o r r e l a t i o n matrix for. fore-s lope sediments c o l l e c t e d i n March, 1974 ( f iner than 80-mesh mate r i a l ; n=21S; r«= ,13 s i g n i f i c a n t at 95% confidence l e v e l ) . 50 e f f i c i e n t s of - .73 and - .87 in t i d a l f l a t and fore-slope samples re spec t ive ly . As t o t a l trace metal contents of marine sediments are often inf luenced by texture, and abundance of organic matter, mafic minerals and hydrous oxides of Fe and Mn (Chester, 1965), i t i s reasonable to reexpress corre la t ions as *.. l i n e a r ; regression equations i n which independent var iables are chosen to represent these c h a r a c t e r i s t i c s . Unfortunately none of the ava i lab le data are f u l l y independent, which places a constra int on in te rpre ta t ion of r e s u l t s . Nevertheless, independent var iables chosen were %sand (to represent sediment texture) , %LI (to represent organic content) , t o t a l Fe (to represent mafic minerals and i ron oxides) and t o t a l Mn ( to represent manganese oxides) . The trace metals were the dependent var i ab le s , and a stepwise mult ip le regression was employed (p. <35) (B jerr ing and Seagraves, 1974). Results (Tables VII and VIII) indica te that , with the exception of Pb i n t i d a l f l a t samples and Ni i n fore-slope samples, combinations of the independent var iables account for more than 60% of v a r i a b i l i t y i n a l l dependent var iab le s . Furthermore a l l dependent var iables except Co are dependent on sand content. How- ever, in the case of N i , unl ike the other trace metals, the regression equations predic t that an increase i n sand content w i l l produce an increase in Ni content. Regression equations there- fore general ly confirm the previous ly observed inverse re l a t ionsh ip between Cu, Pb and Zn values and sediment texture. The degree of dependence i s demonstrated for Zn contents i n fore-s lope samples i n F i g . 16;, where normalized res iduals for the regression of Zn on %sand (r = 81%) are p lo t ted geographical ly . The map suggests 51 Dependent . • „ 2 a Variab le Regression ( r ) Co = 2.6121 + 4.6755 Fe 68% Cu - 40.8860 - .2899 sand 65% N i = -23.2233 +' 32.3235Fe - 3.7563 68% LI + .1644sand Pb = 23.8973 -- .2219sand 28% Zn = 71.769.5 + 3.3345LI - .3068sand 72% 2 a r ~ percent variance accounted for by independent var iab les Table VI I : M u l t i p l e regress ion equations, i n t e r t i d a l sediments c o l l e c t e d i n February 1974 ( f i n e r than 80-mesh mate r i a l ; rj=68). Dependent Var iable Regression ( r 2 ) a Co 6.4548 + 2.94Fe 60% Cu 29.9390 + 5.8956Fe - 0.3026sand 85% N i -0.7848 + 16.9150Fe + 0.1990sand 38% Pb 3.8429 + 0.0403Mn - 0.1377sand 62% Zn 48.4373 + 0.l484Mn - 0.4362sand 88% 2 a r = percent variance accounted for by independent var iab le s Table VI I I : M u l t i p l e regress ion equations, fore- slope sediments c o l l e c t e d i n March 1974 ( f iner than 80-mesh m a t e r i a l ; n=218). 2 • F i g u r e 16: D i s t r i b u t i o n o f n o r m a l i z e d r e s i d u a l s o f t h e r e g r e s s i o n o f Zn on sand c o n t e n t (March s a m p l i n g s e r i e s ) . 53 no w e l l d e f i n e d s u r f i c i a l t r e n d i n Zn v a l u e s i s p r e s e n t o t h e r than t h a t r e l a t e d t o d i s t r i b u t i o n of sediment g r a i n s i z e . Most r e g r e s s i o n e q u a t i o n s i n c l u d e t h e v a r i a b l e s Fe and/or Mn, o f t e n i n c o n j u n c t i o n w i t h t h e o t h e r independent v a r i a b l e s , as, f o r example, i n the c o m b i n a t i o n Mn-%sand which a c c o u n t s f o r 62% and 88% o f the v a r i a b i l i t y i n Pb and Zn d a t a from f o r e - s l o p e s e d i m e n t s . Loss on i g n i t i o n , t o g e t h e r w i t h Fe and/or %sand, c o n t r i b u t e s t o r e g r e s s i o n e q u a t i o n s o f Cu, N i and Zn i n i n t e r t i d a l s e diments and Co i n f o r e - s l o p e s e d i m e n t s . Cu, Pb and Zn c o n c e n t r a t i o n s i n t h e two m e t a l - r i c h t i d a l f l a t samples southwest o f Iona I s l a n d a r e h i g h e r t h a n p r e d - i c t e d by r e g r e s s i o n e q u a t i o n s ( T a b l e I X ) . N o r m a l i z e d r e s i d u a l s of 2.0 and 3.0 s t a n d a r d d e v i a t i o n s r e p r e s e n t 2.5% and .5% f r e q - uency of o c c u r r e n c e r e s p e c t i v e l y . N o r m a l i z e d r e s i d u a l s f o r Cu (4.5 and 3.8), Pb (3.8 and 2.2 ) and Zn (4.4 and 3.1), t h e r e f o r e p r o v i d e e v i d e n c e o f t h e anomalous c h a r a c t e r o f t h e s e samples. S e l e c t i v e C h e m i c a l E x t r a c t i o n E x p e r i m e n t s R e s u l t s o f c o r r e l a t i o n and r e g r e s s i o n a n a l y s i s , though d i f f i c u l t t o i n t e r p r e t i n terms of a c t u a l g e o c h e m i c a l p r o c e s s e s , do suggest t h e t y p e s o f experiments which s h o u l d be u n d e r t a k e n t o d i s c o v e r t h e p h y s i c a l and c h e m i c a l sediment f r a c t i o n s i n which m e t a l s are bound. In t h i s case n e g a t i v e c o r r e l a t i o n s w i t h sand c o n t e n t suggest some of t h e t r a c e m e t a l s a r e perhaps absorbed on f i n e p a r t i c l e s , w h i l e p r e s ence of Fe and/or Mn i n r e g r e s s i o n e q u a t i o n s s u g g e s t s the p o s s i b i l i t y of m e t a l s a s s o c i a t e d w i t h e i t h e r amorphous F-'e> and, Mn o x i d e s o.r -mafic/ m i n e r a l s . 54 Observed Predic ted Normalized Element Value(ppm) Value(ppm) Residual(ppm) Residual Cu 42.6 22.6 20.0 4.5 47.2 30.5 16.7 3.8 Pb 38.9 9.1 29.8 3.8 29.1 12.4 16.7 2.2 Zn 83.4 94.8 58.0 76.7 25.4 18.1 4.4 3.1 a number of standard deviat ions Table IX: Observed, predicted and re s idua l values from regress ion equations (Table VII) for t i d a l f l a t s ta t ions af fected by discharge of meta l - r ich sewage e f f luent . 55 Experiments were t h e r e f o r e undertaken on s e l e c t e d i n t e r t i d a l . and f o r e - s l o p e samples u s i n g 1M MgClg to e x t r a c t metals adsorbed onto s u r f a c e s of p a r t i c l e s (Gibbs, 1973), and 1M hydro- xylamine h y d r o c h l o r i d e i n 25% a c e t i c a c i d (HHA) to d i s s o l v e and e x t r a c t t r a c e metals from amorphous Fe and Mn hydrous o x i d e s (Chester and Hughes, 1967). Residues were taken up i n s t r o n g a c i d s to e x t r a c t metals bound i n d e t r i t a l m i n e r a l l a t t i c e s . The f i r s t experiment i n v o l v e d t r e a t i n g minus80-mesh m a t e r i a l s e q u e n t i a l l y with MgClg, HHA and HNOg-HClO^. R e s u l t s ,(App- endix'B; Table X) show t h a t , with the e x c e p t i o n of the two anomal- ous samples from near Iona I s l a n d , c o n c e n t r a t i o n s of MgClg-extract- able metals are s m a l l compared to hydrous o x i d e - and l a t t i c e - bound forms. In f a c t , l e v e l s of exchangeable Pb, Co and Ni are undetectable, w h i l e Cu l e v e l s are .5ppm and l e s s , and Zn e x t r a c t - able i n MgClg averages .6ppm. Fe i s c o n s i s t e n t l y d e t e c t a b l e i n MgClg-extract with a mean of 5.2ppm, although compared w i t h t o t a l i r o n contents of 2,to 3%, t h i s c o n t r i b u t i o n i s n e g l i g i b l e . MgClg- e x t r a c t a b l e Mn on the o t h e r hand forms an average of 14.2ppm or 5% of t o t a l sediment Mn. C o n c e n t r a t i o n s of Cu, Pb and Zn e x t r a c t e d i n 1M MgClg from the two anomalous s t a t i o n s near Iona I s l a n d are s t r i k i n g l y high compared with l e v e l s i n o t h e r t i d a l f l a t sediments (Table X I ) . HHA e x t r a c t s approximately 10% of the t o t a l Cu, Fe and Ni contents of sediment samples and between 15 and 20% of Zn and Co (Table X). HHA-extractable Mn averages 20% of t o t a l Mn, although the amount e x t r a c t e d v a r i e s from 8.8 to 134ppm. Pb i s the only metal which occurs predominantly i n a form s o l u b l e i n Ext rac t ion (ppm) Element 1.M MgCl 1 HHA HNOg - HC10 1 a Co * * 2.6 1 . 4 - - ,b o . o 11.2 7.2 - 14.6 Cn * 3.5 0.8 - 6.4 23.2 7.6 - 95.8 Fe 5.6 0.24( a \ 10) 2.24(%) 1.9 - 15.2 .11 - .41 1.66 - 3.20 Mn 14.6 60.5 202 0.7 - 37.0 9.8 - 134 158 -- 275 Ni * * 3.8 2.6 - 7.4 36.7 25.7 - 52.9 Pb * 5.7 0.4 - 19.7 * Zn 0.5 11.4 . 5 2 . 1 <0.1 - 1.5 4.1 - 24.7 31.4 - 86.5 a me an b range * not detected in most samples * * not detected in a l l samples Table X: Mean and range of metal values in sequent ia l .extracts of de l t a - f ront sediments (n=37). Extraction(ppm) Element 1M MgCl„ HHA HNO„ - HC10-, £ 2 o 4 Co * * 1.8 3.5 10.9 12.8 Cu 5.9 1.1 15.8 11.2 31.7 34.0 Fe 6.4 6.8 0.21% 0.34% 1.7% 2.4% Mn 1.3 37.9 8.8 64.2 151 217 Ni * * 3.0 4.2 28.2 37.8 Pb 2.2 * 49.7 22.3 9.0 3.0 Zn 6.4 6.8 22.0 26.1 41.6 62.8 * not detected Table XI Sequential extraction of t i d a l f l a t sediments from two stations affected by discharge of metal-rich sewage eff l u e n t 58 HHA, and i s usual ly not detected i n the residue. The second experiment involved leaching of s i l t - p l u s - c lay and sand f ract ions of seven se lected samples with HHA, and subsequent digest ion of s i l t - p l u s - c l a y , l i g h t sand (S.G.^2.89) and heavy sand i n HF-HNOg-HClO^ (p. 28). As in the previous experiment a l l metals except Pb exis t predominantly i n a form inso luble i n HHA (Table X I I ) . ,The s i l t - p l u s - c l a y f r ac t ion i s enriched i n HHA-extractable Cu, Fe, Mn, Pb and Zn, but not Co and N i , compared with the sand f r a c t i o n , although the enrichment factor i s only about 1.5 times. S i l t - p l u s - c l a y contains 5 to 10% of i t s t o t a l Ni and Fe, 15 to 20% of t o t a l Zn, Cu and Mn, and 20 to 25% of t o t a l Co i n HHA-extractable form. A more marked contrast ex i s t s between sand and s i l t - p lus-c lay i n the amount of metals extracted with HF-HNO^-HCIO^ (Table X I I ) . The l a t t e r f r ac t ion contains 1.5 to 3 times more of a l l metals than the l i g h t sand f r a c t i o n . Contrast between the re s idua l metal content of the l i g h t and heavy sand f ract ions i s even greater. Average enrichment factors i n the heavy f r ac t ion are 2.3x (Cu), 3.9x (Zn), 4.8x (Ni ) , 6.2x (Fe) , 7.Ox (Co) and 9.2x (Mn). A l l heavy sand samples contain s i m i l a r metal values, although the contr ibut ion to t o t a l values w i l l d i f f e r since heavy sand ranges from 2 to 25% of the samples by weight. :" :' Discuss ion Tota l metal contents df nearshore- sediments from sever- a l l o c a l i t i e s inc luding the Fraser de l ta fore-slope are l i s t e d in 59 Metal Contents of Extraction?! (ppm) Sample and Fraction HHA HF-HNOj -HC10. 4 Co Cu Fe(S) Mn Ni Zn Co Cu FeCo) Mn Ni Zn Heavy Sand Minerals (%) (%) A4 -270J 4.9 S.4 .38 64.2 5.9 13.0 14.6 27.8 4.19 489 54.4 83.1 +270 5 .0 3.6 .26 47.1 5.2 10.4 6.2C 13.4 1.69 201 31.0 43.5 50.0 31.7d 24.5 10.0 1770 116 147 5.8 A21 -270 5 .4 3.2 . 33 41.0 4.3 13.0 14.7 19.4 4.34 562 52.5 80.5 +270 4 .8 2.3 .27 39.8 3.7 12.6 3.3 11.0 1.39 186 24.7 40. 3 65.8 31.2 27.5 10.6 1940 118 160 7.8 A25 • 270 6 .1 3.2 .18 49.6 6.5 5.9 3.3 12.2 1.20 176 17.3 32.3 94.9 34.8 24.5 10.8 2410 166 120 26.4 A53 -270 4 .9 4.7 .31 132 2.9 15.7 15.2 25.4 4.37 599 49.7 99.7 •270 6 .2 4.1 .29 97.1 4.4 14.4 4.4 15.8 1.34 171 28.9 37.6 60.6 36.6 39.5 9.51 1830 125 168 5.2 B32 -270 3. 8 6.0 .40 94.7 4.4 19.3 14.8 33.8 3.79 379 45.1 88.5 •270 7. 4 4.1 .33 53.2 5.4 13.0 5.1 17.0 1.67 176 28.0 13.5 55.8 31.2 36.5 9.92 1700 109 159 5.0 B119 -270 3. .1 7.1 .35 75.2 5.9 17.1 13.6 35.0 3.62 445 48.9 88.2 +270 3. 5 5.0 .32 58.1 6.2 12.6 4.4 20.6 1.91 246 36.0 53.0 22.8 38.0 54.5 11.2 1950 110 199 1.7 B214 -270 3. 6 4.9 .37 125 6.2 17.1 12.5 38.6 3.82 445 41.1 87.6 +270 5. 1 3.4 .33 100 6.1 12.6 8.3 21.8 1.94 202 27.6 51.6 40.2 38.0 54.5 11.7 1660 117 176 3.4 a s l l t - p l u s - c l a y b sand c light sand (S.G.^2.89) d heavy sand (S.G.^2.89) Table XII: Sequential extraction of delta-front sediments; partitioning of metals between IIHA-oxtractable and HF-HNO--HC10 extractable s i l t - p l u s - c l a y and sand. 60 Table XIII . Rigorous comparisons are not poss ible as sediment textures and materials d i f f e r between various l o c a l i t i e s , as do degrees of i n d u s t r i a l contamination. Moreover d i f ferent sediment f ract ions and digest ion techniques are used by various l abora tor ie s , r e s u l t i n g in d i f ferent proportions of t o t a l metal being i s o l a t e d . Despite these incons i s tencies the s i m i l a r i t y of Fraser de l ta- f ront sediments and those from other regions i n terms of trace metal contents i s s t r i k i n g . The Fraser de l ta - front contains r e l a t i v e l y high values of t o t a l sediment Zn, Ni and Cu, and r e l a t i v e l y low values of Mn. when compared with most regions ( q . v . , Gupta and Chen, 1975; S l a t t , 1974; Perkins e_t a l , 1973; H i r s t , 1962b). Po l lu ted sediments (Severn and Clyde estu- ar ies ) contain considerably elevated va.lues of Pb, Zn, Fe and Mn, and Co and Cu in the case of the Clyde, compared with Fraser sediments (Perkins e_t a l , 1973'; Chester and Stoner, 1975). Geographic trends of trace metals i n s u r f i c i a l sediments of the Fraser de l t a - f ront , and cor re l a t i on and regression analyses of metal d a t a , a l l ind ica te an inverse r e l a t i o n s h i p between the metals s tudied (except Ni) and sand content of the sediment (Figs . 7 to 16; Tables V to VI I I ) . In other words f ine sediments and sediment f rac t ions contain higher concentrations of Co, Cu, Fe, Mn, Pb and Zn than sands. This in terpre ta t ion i s corroborated by s e l ec t ive extract ion experiments in which a l l metals except Co and Ni are enriched i n the HHA-extractable f r ac t ion of s i l t - p l u s - c lay , and a l l metals are enriched in the s i l t - p l u s - c l a y residue after HHA leaching ( ignoring the heavy sand f r a c t i o n ) . 61 £° Fe(_%) Mn Ni Pb Zn Fraser de l ta- f ront f o r e s l o p e (sands and s i l t s ) ( th i s study) 13 30 2.3 327 48 11 77 Los Angeles Harbour ( s i l t y sand) (Gupta and Chen, 1975) - 35 2.9 381 18 32 94 Conception Bay (muddy sand) ( S l a t t , 1974) 23 25 3.2 490 51 - 50 Solway F i r t h (^204um f rac t ion) (Perkins et a l , 1973) 16 10 2.0 360 38 37 63 Boca Vagre de l ta (sands and s i l t s ) ( H i r s t , 1962 a,b) 6.5 10 2.5 375 20 14 Severn estuary (^61um f rac t ion) (Chester and Stoner, 1975) 7 38 4.5 1820 36 119 280 Clyde estuary' ( s i l t ) (Perkins et a l , 1973) 60 225 9.4 1600 69 528 1680 a described as " p o l l u t e d " Table XIII : Mean t o t a l metal contents (ppm) of nearshore sediments. 62 Assoc ia t ion of metals with f ine mater ia l has often been described i n nearshore sediments (q. v. , S l a t t , 1975; Perkins et a l , 1973; Gupta and Chen, 1975), although few workers provide ev id- ence to describe the nature of th i s a s soc ia t ion . Trace metals i n marine sediments are known to occur i n various forms, i n c l u d i n g : i ) incorporated in l i v i n g and decayed organic mater i a l ; i i ) adsor- bed on surfaces of c l ay- s i ze and c o l l o i d a l p a r t i c l e s of c l ays , organic mater ia l and amorphous hydrous i ron and manganese oxides; i i i ) bound in hydrous i ron and manganese oxides of weathering, f l u v i a l and marine o r i g i n ; and iv ) as constituent cations i n l a t t i c e s of d e t r i t a l minerals (Chester, 1965; Krauskopf, 1956; Gupta and Chen, 1975; Chester and Stoner, 1975; Cooper and H a r r i s , 1974; Nissembaum and Swaine, 1976). The sequential extract ion procedures used i n th i s study were designed to i s o l a t e metals associated with forms i i ) , i i i ) and i v ) . Organica l ly bound metals were not analysed because organic matter content of d e l t a - front sediments i s low (Appendix A ) , and because s t a t i s t i c a l analys i s indicates fewer corre la t ions and dependencies between trace metals and %LI than between trace metals and %sand, Fe and Mn. Abundance of surface-sorbed metals has commonly been in fe r red from inverse metal-grain s ize re l a t ions (q!. v., S l a t t , 1974). In the case of the Fraser delta-froritlow MgClg-soluble metal values (except Mn) m i l i t a t e against t h i s i n t e r p r e t a t i o n . The general ly sandy and s i I t y nature of i n t e r t i d a l and fore-slope sediments probably accounts for the small contr ibut ion of an ad- sorbed metal f r a c t i o n . Low and non-detectable concentrations of adsorbed Cu, Pb, Ni and Zn are s i m i l a r to re su l t s of Gupta and Chen (1975) for s i l t y sediments from Los Angeles Harbour. Adsorbed Mn in Fraser de l ta- f ront sediments i s one order of magnitude high- er than in Los Angeles Harbour sediments, whereas adsorbed Fe i s one order of magnitude lower, despite s i m i l a r t o t a l Mn and Fe contents (Table XII I ) . High exchangeable Mn .values are reported for sediments of the Hudson estuary (McCrone, 1967), but are re la ted there to increased s o l u b i l i t y of Mn in reducing condi t ions . Assoc ia t ion of almost a l l Pb and 10 to 20% of other metals with materia l soluble in HHA p a r t i a l l y accounts for assoc- i a t i o n of metals with f ine sediment. Further , resu l t s suggest that large proportions of trace mtals are bound in amorphous Fe and Mn hydrous oxides (Chester and Hughes, 1967). These oxides are ubiquitous in surface sediments in contact with oxygenated waters. They form, both as coatings on par t i cu le s and as free c o l l o i d s , i n s o i l (Jenne, 1968), stream (Foster and Hunt, 1975), estuarine (Lowman e_t a l , 1966) and oceanic environments (Goldberg, 1954). Their capacity to scavenge metal ions, both as adsorbed and coprec ip i ta ted species, i s we l l known (Lee, 1975; Jenne, 1968; Krauskopf, 1956; Kharkar et a_l, 1968) and accounts for high trace metal leve l s i n , for example, s o i l p a r t i c l e coatings and marine ferromanganese nodules. Metals associated with hydrous oxides can be compared with those associated with the "nodular hydrogenous f r a c t i o n " of Los Angeles Harbour sediments (Gupta and Chen, 1975) and the HHA-leachable f r ac t ion of po l lu ted Severn Estuary sediments (Ches- ter and Stoner,1975) (Table XIV). Pb proportions i n Fraser Co Cu Fe Mn Ni Pb Zn Fraser de l ta- f ront "^Sum Metals extractable i n HHAa ( th i s study) 23 15 8 15D 9 <100C 16 Severn estuary <61um Metals extractable i n HHAa (Chester and Stoner, 1975) 33 43 54 80 33 68 68 Los Angeles Harbour sediment Metals extractable i n NH20H-HC1 i n HNO and i n HHA at 1 0 0 ° C (Gupta and Chen, 1975) - 10 12 12 22 48 29 a average values b contains a s i g n i f i c a n t proport ion of adsorbed Mn c Pb not detected i n HHA residues d sandy s i l t sample; 48% >50um Table XIV: Proport ion of metals (%) i n hydrous oxide phases of nearshore sediments. Co Cu Fe Mn Ni Pb Zn ( th i s study) 77 75 92 75 91 * 74 Fraser de l ta- f ront <53uma c l Severn estuary <61um (Chester and Stoner, 1975) 67 57 46 20 67 32 32 Los Angeles Harbour sediment (Gupta and Chen, 1975) 88 77 75 63 35 37 a average values b sandy s i l t sample; 48%>50um * a l l values below detect ion l i m i t Table XV: Proport ion of metals (%) in d e t r i t a l minerals of nearshore sediments. 65 del ta- front sediments are much higher than those from the other l o c a l i t i e s , whereas f rac t ions of Ni and Zn are lower. In a l l three l o c a l i t i e s the r e l a t i v e order of enrichment Pb>Zn>Cu i s obeyed. Trace metals bound i n hydrous Fe and Mn oxides i n Fraser de l ta- f ront sediments poss ibly represent metals scavenged i n weathering environments of the Fraser drainage bas in . A further contr ibut ion of Zn and Cu and probably other metals to the HHA-soluble f r ac t ion i s formed on suspended sediments wi th in the main channel between Steveston and Sand Heads (Chapter V I ) . The largest proportion of Co, Cu, Fe, Mn, Ni and Zn i s associated with the HHA-residue (Tables X and XII) and thus represents metals bound in c r y s t a l l i n e minerals of d e t r i t a l : o r i g i n . The fine f ract ions are again enriched in th i s form of metal, although heavy minerals i n the sand f r a c t i o n p a r t i a l l y counteract th i s r e l a t i o n s h i p . Minerals i n the s i l t - p l u s - c l a y f r a c t i o n where- i n trace metals can subst i tute for magnesium and ferrous i ron i n l a t t i c e s i t e s include amphiboles, micas and c h l o r i t e s . Heavy sand iron-bearing minerals include amphiboles, epidote, b i o t i t e and magnetite. Proportions of la t t ice-bound i ron and trace metals are greatest i n nearshore sediments (Chester and Messiha-Hanna, 1970), s ince accumulation of terrigenous sediment i s greatest i n nearshore regions. Importance of th i s associat ion has been demonstrated in the Severn estuary (Chester and Stoner, 1975), Los Angeles Harbour (Gupta and Chen, 1975) (Table XV) and the Gulf of P a r i a ( H i r s t , 1962a,b). Content and d i s t r i b u t i o n of t o t a l metals in Fraser de l ta - front sediments are therefore determined pr imar i ly by r e l a t i v e 66 abundances of s i l t - p l u s - c l a y , l i g h t sand and heavy; sand. In other words the c o n t r o l l i n g factors are sediment transportation and sorting mechanisms which determine sediment texture. For example, accumulation of fine-grained material i n s a l t marshes and on the fore-slope west of Sturgeon Bank res u l t s in high t o t a l metal contents because of the general enrichment of fine material in hydrous oxide- and lattice-bound metals. Introduction of metal- poor sand w i l l produce lower t o t a l metal concentrations i n a sed- iment, as in the region immediately west of the mouth of the North Arm. In l o c a l conditions of active winnowing by currents, as on the sand f l a t s , and/or net removal of sediment, as on the fore- slope west of Roberts Bank, r e l a t i v e accumulation of metal-rich heavy minerals may p a r t i a l l y counteract the dilutant effect of sand. Sporadic high values of metals such as Mn, Fe, Ni and Co, which are most enriched i n heavy sand, w i l l r e s u l t . Each metal i s affected to a d i f f e r e n t degree by these processes, depending upon, among other factors, proportion of t o t a l metal i n the HHA-soluble f r a c t i o n , and proportions of HHA'- and acid-extractable metal i n s i l t - p l u s - c l a y and sand. While the o v e r a l l balance i s very complex (and undoubtedly involves more factors than those discussed here), the predominant effect of sediment texture can be demonstrated i n the cases of two extremes: i ) For zinc, a metal which occurs i n greatest concent- ration i n HHA- and acid-extractable s i l t - p l u s - c l a y (Table XII), and whose enrichment i n heavy sand i s r e l a t i v e l y low, a clear inverse geographic r e l a t i o n exists between t o t a l zinc and sand content of sediments (Figs. 13 and 15). This i s r e f l e c t e d i n 67 s t a t i s t i c a l a n a l y s e s ( T a b l e s V t o V I I I ) w h i c h show s t r o n g n e g a t i v e c o r r e l a t i o n s between t o t a l Zn and s a n d c o n t e n t and a s t r o n g dependence o f Zn on s a n d c o n t e n t , i i ) N i c k e l i s n o t e n r i c h e d i n s i l t - p l u s - c l a y i n t h e H H A - e x t r a c t a b l e f r a c t i o n ( T a b l e X I I ) . F u r t h e r m o r e i t i s r e l a t i v e l y c o n c e n t r a t e d i n h e a v y s a n d . C o n s e q u e n t l y g e o g r a p h i c d i s t r i b u t i o n a p p e a r s random and no r e l a t i o n t o g r a i n s i z e d i s t r i b u t i o n i s a p p a r e n t ( F i g . 1 1 ) . N o n s i g n i f i c a n t c o r r e l a t i o n s w i t h s a n d c o n t e n t t h u s r e s u l t f r o m a s s o c i a t i o n w i t h b o t h s i l t - p l u s - c l a y and s a n d t o a p p r o x i m a t e l y e q u i v a l e n t e x t e n t s . L e a d , b e i n g p r e s e n t p r e d o m i n a n t l y i n H H A - e x t r a c t a b l e f o r m and p r e d o m i n a n t l y i n s i l t - p l u s - c l a y , d i s p l a y s w e l l - d e f i n e d g e o g r a p h i c t r e n d s and s t r o n g t e x t u r a l c o r r e l a t i o n s s i m i l a r t o z i n c ( T a b l e s V and V I ; F i g s . 12 and 1 3 ) . O t h e r m e t a l s show b e h a v - i o u r i n t e r m e d i a t e between z i n c and n i c k e l , d e p e n d e n t upon f a c t o r s d i s c u s s e d above. In t h e v i c i n i t y o f I o n a I s l a n d t h e above n a t u r a l mech- anisms a r e o v e r s h a d o w e d by d i s c h a r g e f r o m t h e G r e a t e r V a n c o u v e r R e g i o n a l D i s t r i c t p r i m a r y sewage t r e a t m e n t p l a n t . Two s a m p l i n g s t a t i o n s a r e d e f i n e d as anomalous i n t o t a l Cu, Pb a n d Zn c o n t e n t s on t h e b a s i s o f r e g r e s s i o n a n a l y s i s ( T a b l e I X ) . T h e s e two s a m p l e s a r e f u r t h e r d i s t i n g u i s h e d by c o n c e n t r a t i o n s o f M g C l 2 - e x t - r a c t a b l e Cu, Pb and Zn w h i c h a r e an o r d e r o f m a g n i t u d e h i g h e r t h a n o t h e r d e l t a - f r o n t s a m p l e s , and l e v e l s o f H H A - e x t r a c t a b l e m e t a l s w h i c h a r e a l s o n o t i c e a b l y h i g h ( T a b l e X I ) . 68 H a l l e_t a_l (1975) report high di s so lved l eve l s of Cu (105ug/l) , Zn (108ug/l) and Pb (39ug/l) in wastewater entering the Iona Island sewage treatment p lant . The fate of metals i n e f f l u - ent from th i s plant i s impossible to delineate on the bas is of low density sediment sampling. Galloway ( i n Rohatgi and Chen, 1975) estimated that less than 15% of sewage-transported metal i s account- ed for in sediments adjacent to southern C a l i f o r n i a o u t f a l l s . Rohatgi and Chen (1975) a t t r ibute th i s loss of metal to mixing and d i l u t i o n of d i s so lved metals with sea water, and mobi l i za t ion of metals associated with sewage p a r t i c u l a t e s . This in te rpre ta t ion may be v a l i d as t i d a l act ion at the Fraser de l ta- f ront allows for rapid mixing of waste and marine waters. Furthermore, presence of MgClg-extractable contaminant metals in sediments rece iv ing Iona Is land ef f luent p a r t i c l e s suggests that considerable quant i t - ies of waste par t i cu la te metal are ea s i ly exchanged and mobi l ized by cations in sea water. No doubt the organic f r ac t ion of sewage eff luent i s a lso important i n transportat ion of metals. Par t i cu l a te organic matter and associated metals may be deposited near the o u t f a l l , as observed in sediments adjacent to Los Angeles County sewage o u t f a l l s (Bruland ejt a l , 1975). Soluble organic matter in treated sewage may also affect metal pathways by complexing metals, thus in f luenc ing t h e i r s o l u b i l i t i e s , and sorpt ion and mobi l i za t ion propert ies (Murray and Meinke, 1974"; Theis and Singer, 1974; Rashid and Leonard, 1973). In summary, trace metals i n s u r f i c i a l sediments are predominantly bound i n l a t t i c e s of d e t r i t a l minerals . Relat ive 69 e n r i c h m e n t o f most m e t a l s i n t h e H H A - e x t r a c t a b l e and HNO^-HCIO^- e x t r a c t a b l e f r a c t i o n s o f s i l t - p l u s - c l a y compared w i t h s a n d , and e n r i c h m e n t o f a l l m e t a l s s t u d i e d i n hea v y s a n d m i n e r a l s , a c c o u n t s f o r t o t a l c o n t e n t s o f m e t a l s i n s u r f i c i a l s e d i m e n t s . P h y s i c a l s e d i m e n t t r a n s p o r t a t i o n and d e p o s i t i o n mechanisms d e t e r m i n e d i s t - r i b u t i o n o f m e t a l s on t h e F r a s e r d e l t a - f r o n t . 70 CHAPTER V: TRACE METALS IN BURIED INTERTIDAL SEDIMENTS OF THE FRASER RIVER DELTA-FRONT Introduction To determine i f s u r f i c i a l metal values are continued at depth i n sediments, a ser ies of short cores was c o l l e c t e d from i n t e r t i d a l regions of the Fraser de l ta- f ront ( F i g . 5). Factors expected to produce var iable metal p r o f i l e s include textura l va r i a t ions , post-depos i t ional chemical changes, and changes in rate of metal input r e s u l t i n g from natura l or man- made causes. Results Metal contents of 5cm subsamples of short cores c o l l e c t e d at locat ions shown in F i g . 5 are l i s t e d in Appendix C. Selected cores are shown i n F i g . 17; average metal values of cores relevant to fol lowing discussions are l i s t e d i n Table XVI. The most s t r i k i n g feature of short core data i s the general uniformity of metal values throughout the depths sampled, p a r t i c u l a r l y in cores of uniform texture (e.g. , cores 16, 18, 31 and 34) (F ig . 17; Plate 1).; Secondly, var i a t ions between core averages tend to be of the same order as var ia t ions between surface metalr: leve l s over the i n t e r t i d a l area. This i s demonst- rated by comparing average Zn values i n core 34 (68ppm), a f i n e - grained sa l t marsh sample, and core 18 (38ppm), a coarse-grained CORE 34 Co Zn Cu 14 71 36 15 71 32 14 66 36 15 72 36 14 66 31 14 68 34 16 70 37 15 70 37 14 63 31 15 69 34 14 70 35 13 62 31 12 65 30 13 69 32 SALT MARSH 4m PREDOMINANTLY S I L T CORE 38 Co Zn Cu 13 61 26 13 56 27 12 57 28 8 46 18 7 45 17 10 45 16 10 47 16 9 39 16 .8 40 17 8 31 18 8 38 18 9 44 19 11 42 20 'IDAL FLATS PREDOMINANTLY SAND CORE 16 Co Zn Cu 12 48 14 12 45 12 12 48 14 13 45 12 12 43 14 9 39 12 12 47 17 8 36 12 10 38 14 11 36 14 9 35 13 10 35 13 9 35 13 2 . 5m ELEVATIONS RELATIVE TO CHART DATUM HORIZONTAL AND VERTICAL SCALES ARBITRARY F i g u r e 17: S c h e m a t i c s e c t i o n o f Co, Zn and Cu v a l u e s (ppm) i n 5cm-subsamples o f s u b s u r f a c e s e d i m e n t s f r o m R o b e r t s Bank. 72 t i d a l f l a t sample, with the s u r f i c i a l range in Zn concentrations i n February i n t e r t i d a l samples (38 to 79ppm). Between these two extremes, a core from the f luc tua t ing environment near the seaward edge of the marsh (e.g. , core 37) contains intermediate mean Zn values (59ppm). This comparison suggests trace metal concentrations at depth large ly depend on texture, and perhaps other sediment propert ies , to a degree s i m i l a r to s u r f i c i a l sediments. I t " i s expected, therefore, that a core with var iable texture should contain var iab le metal concentrations. Core 38, for example, contains t i d a l f l a t sediments over la in by sediments t y p i c a l of the leading edge of the s a l t marsh (Plate 1), r e s u l t i n g in an average Zn content increase from 42.8 to 61.4ppm, values t y p i c a l of uniform cores from these two environments ( F i g . 17). A l l metals except Ni are s i m i l a r l y affected (F ig . 17; Appendix C) . Cores 19 and 35 also display abrupt s h i f t s i n mean metal contents r e s u l t i n g from rap id facies f luctuat ions (Appendix C) . Gradual f luc tua t ion of metal p r o f i l e s are due to more subtle grain s i ze f luc tuat ions , as in core 33. Here values of Zn, for example, increase from 60 to 75ppm over a range of 70cm, i n which i n t e r v a l the sand population becomes less dominant (Appendix C) . A very pronounced facies change from an o rgan ic - r i ch mud to f ine sand occurs at 12cm depth i n core 30, c o l l e c t e d adj- acent to the Iona Island sewage eff luent o u t f a l l channel, within lkm of the point of discharge ( F i g . 5) . The s u r f i c i a l mud, which represents deposit ion s ince the blocking of MacDonald channel i n combination with sedimentation of f ine par t i cu la te s from sewage discharge since 1963, contains leve l s of Cu, Pb and Zn (43, 29 Average MetaI Contents(ppm) Location Core Co Cu Fe >(%: I Mn Ni Pb Zn %sand 16 10.6 4 1. 99 234 44 .4 * 40. 8 95.4 T i d a l F la t s 18 9.3 15. 6 1. 84 240 38 .3 * 38. 0 29 a 10.6 14. 8 1. 74 179 38 .2 * 43. 0 92.5 38 11.7 27. 7 2. 36 234 43 .2 6.8 63. 1 53.5 19 10.2 b 23. 3 2. 14 265 39 .6 * 48. 5 75.4 8 . 8 ° 15. 4 1. 89 265 37 . 5 * 38. 2 96.0 Varying condit ions 35 12.0 27. 3 2. 42 278 42 .5 11.0 64. 5 10. 3 18. 4 2. 08 232 38 . 1 * 46. 2 37 12.8 28. 6 2. 55 325 45 .9 59. 6 38 13.1 30. 1 2 . 73 348 46 .0 5.1 61. 4 8.9 17. 4 2. 15 257 40 .7 * 42 . 8 31 12.1 33. 5 2. 55 306 57 •8 * 65. 0 43.2 Sal t marsh 34 14.2 33. 9 2. 67 269 45 .9 6.6 68. 2 26.0 * some or a l l values below detect ion l i m i t a excluding 21-31cm depth por t ion b upper f ine-gra ined por t ion c lower coarse-grained por t ion Table XVI Average metal content and sand content of i n t e r t i d a l sediment cores . 74 and 88ppm respect ive ly) s i m i l a r to contaminated surface samples from t h i s region (Table IX).. By comparing average metal values for cores of uniform texture with values predicted by the regression equations comp- uted for s u r f i c i a l samples (Table XVII) , i t may be poss ible to detect changes in metal concentration brought about by post- depos i t iona l processes or change of metal input rate to the de l ta- front . The mean for Cu i n a t i d a l f l a t core (16), for example, i s 13.4ppm, compared with a value of 13.2ppm predicted by regre- ss ion based on i t s sand content. Cu content i n two s a l t marsh cores (33 and 34) predicted by regression (25.5 and 33.6ppm resp- e c t i v e l y ) are also very close to actual mean values of 27.7 and 33.9ppm. Core 31, with 33.5ppm Cu, contains 5ppm more than predic ted . Zn and Co means i n short cores, on the other hand, are roughly 10% lower than predicted values, while Ni means are 10 to 20% lower (Table XVII) . The Fe values are 10 to 15% higher than predicted by a regression equation based on sand content. Mean values of Pb i n cores 33 and 34 are 45% and 60% 2 lower respect ive ly than predicted values. However, since r =28% in the case of Pb regression on sand t h i s re su l t should not be considered r e l i a b l e . A s i m i l a r comparison of Mn values cannot be made as Mn does not corre la te s i g n i f i c a n t l y with sand content in t i d a l f l a t sediments. Discuss ion General uniformity of metal p r o f i l e s i n short cores, other than those containing facies changes and obvious textura l Actual Predicted Element content(ppm) value^Tppm) Residual(ppm) Co 10.6 11.9 -1.3 Cu 13.4 13.2 -i-0.2 Fe 1.99(%) 1.73(%) +0..26(%) Ni 44.4 51.4 -7.0 Pb * Zn 40.8 47.0 -6.2 Co 12.1 14.5 -2.4 Cu 33.5 28.5 +5.0 Fe 2.55(%) 2.22(%) +0.33(%) Ni 51.8 58.4 -6.6 Pb * Zn 65.0 69.1 -4.1 Co 11.7 13.6 -1.9 Cu 27.7 25.5 +2,2 Fe 2.36(%) . 2.12(%) +0.24(%) Ni 43.2 55.3 -12.1 Pb 6.6 12.0 -5.4 Zn 63.1 64.7 -1.6 Co 14.2 15.1 -0.9 Cu 33.6 33.9 +0.3 Fe 2.67(7o) 2.37(%) +0.30(%) Ni 45.3 58.2 -12.9 Pb 6.8 18.1 -11.3 Zn 68.2 76.4 -8.2 * some or a l l values below detection l i m i t a Regressions Co Cu Fe Ni Pb Zn Table XVII: Predicted and residual values of. average metal contents in i n t e r t i d a l sediment cores; regression equations taken from data for February t i d a l f l a t samples. = 2.6121 + 4.6755(Fe) r^=68% = 41.2767 - .2947 (%sand) r£=65% = 6.2186 - .009337 (%sand) r =54% =-23.3637 + 32.3235(Fe) p -3.7909(%LI) + .1689(%sand) r^=67% = 23.8973 - .2219(%sand) r^=28% = 87.3560 - .4428(%Sand) r"=67% 76 v a r i a t i o n s , and s i m i l a r ranges of t o t a l metal contents i n core and surface samples over the i n t e r t i d a l region, are re la ted to the preponderance of trace metals associated with d e t r i t a l minerals in t h i s area (Chapter IV) . In other words the bulk of deposited metals (excepting Pb) i s unavai lable for chemical react ions under ear ly diagenetic condit ions . However, apparent losses of Pb, Zn, Co and Ni from buried sediments (Table XVII) suggests, assuming metal input has been constant with time, some post-depos i t ional mobi l i za t ion of these metals. The f rac t ions of metal affected are uncertain without further analysis,,;, but they are most l i k e l y the adsorbed and hydrous oxide-associated f r ac t ions . In support, the apparent losses of Zn, Co and Ni are s imi l a r to HHA-extractable proportions of t o t a l metal (Tables X and XII ) , and Pb, the metal most enriched in HHA-extract, exhib i t s by far the largest apparent los s . Duchart e_t a l (1973) have suggested that Fe and Mn oxides are s o l u b i l i z e d at depth i n sediments as a re su l t of decreasing Eh, with consequent release of sorbed and coprec ip i ta ted trace metals. Once mobi l ized i n th i s manner into i n t e r s t i t i a l waters, organic complexing may maintain metals i n soluble form (Presley et a l , 1 9 7 2 ; , E l d e r f i e l d and Hepworth, 1975; Duinker ejt a l , 1974). Metals may subseque- nt ly be transported to the sediment surface by d i f fu s ion (Elder- f i e l d and Hepworth, 1975) p a r t i c u l a r l y i n areas experiencing high current v e l o c i t i e s (Duinker et a l , 1974) . M i l i t a t i n g against th i s in te rpre ta t ion are several factors , inc luding the lack of d i rec t a n a l y t i c a l evidence of metal forms and Eh conditions at depth. Further , Cu and Fe are appar- ent ly not mobi l ized , yet are known to occur i n hydrous oxides to the same extent as other metals. The behaviour of Fe data i n p a r t i c u l a r suggests e i ther the presence or nature of the mobi l- i z a t i o n process i s i n d e f i n i t e . F i n a l l y , the assumption that metal input to the de l ta- f ront has been constant over the time represented by the cores, must be suspect. At least in the. Iona discharge area (Core 30) there i s d e f i n i t e evidence of the r e l a t i v e l y recent introduct ion of meta l -r ich contaminated organ ic- r i ch muds. Contaminated l eve l s of trace metals i n bottom sediments of the lower Fraser (Ha l l and Fletcher,1974) would lead one to expect higher concentrations of metals in sed i - ments reaching the ent i re de l ta- f ront today. The problem of pos t -bur i a l metal mobi l i za t ion w i l l be resolved by p a r t i a l extract ion of metals in subsurface samples, and analys i s of i n t e r s t i t i a l waters. Detect ion of changing metal input rates w i l l be d i f f i c u l t , e spec i a l ly i f diagenetic factors are inf luencing subsurface metal concentrations. C o l l - ect ion of longer cores in areas of continuous undisturbed sed i - mentation would be h e l p f u l , i n case a marked t r a n s i t i o n exi s t s at depths greater than those sampled i n th i s study. 78 CHAPTER VI : INTERACTIONS BETWEEN SUSPENDED SEDIMENT AND TRACE METALS IN THE MAIN CHANNEL OF THE FRASER RIVER Introduction Rivers carry both di s so lved and sediment-bound metal, cons t i tu t ing the greatest proport ion of metal input to the oceans (Gibbs, 1973; Turekian, 1971). However, few deta i l ed studies have been c a r r i e d out to determine amount and mode of metal transport i n r i v e r s , and fewer s t i l l describe processes occurr ing in the t r a n s i t i o n from fresh to sa l ine condi t ions . Es tuar ies , where e f fects of various degrees of in te rac t ion between r i v e r and marine materials can be observed, are the s i t e s where these t r ans i t i ons occur. Suspended sediment-metal in terac t ions have been invest- igated to discern changes in metal a s soc ia t ion wi th in estuarine portions of the Fraser River , and to determine i f metal contents wi th in s u r f i c i a l sediments of the del ta- front (Chapter IV) r e f l e c t processes occurr ing after encounter of brackish or marine condi t ions . In the l i g h t of other studies (e .g . , B u r r e l l , 1973; Thomas, 1975; Lowman, 1966; de Groot, 1973), th i s inves t i ga t ion was designed to detect sorpt ion and desorption processes invo lv ing par t i cu la te and d i s so lved metals. Sampling was ca r r i ed out on August 19, 20 and 21, 1975, when the Fraser River discharge at Agassiz was 2830m /sec. 79 Results Locations of lm-depth sampling s ta t ions within the main channel are shown i n F i g . 18, along with conduct iv i t i e s of water and r e l a t i o n of sampling times to t i d a l cyc le s . Tides were delayed moving upr iver , up to a t o t a l of three hours at Stat ion 9. Stat ions 2 through 5 were purposefully sampled near high t ides to coincide with penetrat ion of the s a l t water i n t r u s - i o n . Samples were c o l l e c t e d at depth i n sa l ine water at s tat ions 3, 4 and 5. Suspended sediment l eve l s at lm depth decrease s t ead i ly from 25mg/l at s t a t ion 9 to 4mg/l at s t a t ion 2, except for the increase observed between s tat ions 8 and 7 (F ig . 19). Only a small change was found between s tat ions 5 and 4. Tota l par t i cu la te major elements (Ca, Mg, Na and K) per weight of par t i cu la te s are roughly constant, and thus values of these elements per volume of water p a r a l l e l the decrease in suspended sediments moving down- r i v e r (Table XVIII ) . Data of t o t a l and HHA-extractable suspended Zn (Zn and Zn ), Fe (Fe and Fe ) and Mn (Mn and Mn ), t o t a l suspended Cu 6 S 0 S " ( C u g ) , and dis so lved Zn (Zn^), Cu (Cu^) and Fe (Fe^) are d i sp lay- ed in F i g . 19 and Table XIX. Changes i n concentration of t o t a l suspended Fe and Mn c lo se ly follow var ia t ions in suspended sedi- ment load , s i m i l a r l y to the major cat ions . Suspended Zn follows the same trend i n the fresh water between s tat ions 9 and 5. Howe- ver, i n the brackish waters between s tat ions 5 and 4 there i s an increase from 2 .8ug/ l to 5 .8ug / l , equivalent to a change of 167ppm to 349ppm dryweight of sediment. Concentrations of d i s so lved Zn Figure 18: Sampling s ta t ions i n the Fraser River with conduc t iv i ty (uiuho/cm at lm depth) i n parentheses. Sampling times are shown r e l a t i v e to t i d a l f luc tua t ions at Vancouver; extremes are progres s ive ly delayed upr iver up to a maximum of three hours at s t a t i o n 9. oo o 2 3 4 5 6 7 8 9 STATION Figure 19: Var ia t ions i n Fraser River water contents of : suspended sediment; t o t a l suspended Fe (Fe ) and Zn ( Z n g ) ; hydroxylamine hydrochlor ide-acet ic ac id-extractable Zn (Zn ); and d i s so lved Zn (Zn, ) . 82 M a j o r E l e m e n t s _ ( u g / 1 ) Suspended S t a t i o n Sediments (mg/1)_ CaO MgO Na 20 K 2 ° 9 25. 7 604 745 337 493 8 25.5 602 783 342 520 7 32.7 7 58 916 461 611 6 21. G 512 667 279 445 5 16. 9 352 466 213 304 4 16. 7 337 448 205 294 3 11.7 227 339 162 219 r» 4.41 90. 4 106 77.2 82.0 T a b l e X V I I I : Weight o f suspended s e d i m e n t s and suspended major elements i n samples from the F r a s e r R i v e r . Metals S t a t i o n Conductivity(umho/cm) Zn Cu Fe Mn Z n / Z n s b Z » s C Zn e e r< a C u d Cu s* <V a F e d Fe s Fe d s Mn s Mn c s Mn 6 e 9 120 <1 2. 39 165 43 2. 6 1. 80 69.9 3 1130 4. 4 .26 21.5 838 232 8 106 <1 4. 89 191 40 2. 1 1. 92 75. 3 3 1210 4. 8 . 30 23.4 919 257 7 122 1.1 5. 83 150 57 2. 3 2. 06 63.0 6 1370 4. 2 .16 27.4 839 188 6 125 1.1 2 . 82 178 41 2. 3 1. 59 73.7 3 1020 4. 7 . 35 19.9 921 290 5 570 <1 3. 84 167 31 2. 2 1. 20 71.2 3 723 4. 3 .29 13. 8 819 275 4 400 2.6 4. 91 349 190 2. 7 1. 59 95. 3 3 690 4. 1 .35 13. 3 794 313 3 9000 2.9 4. 87 418 219 2. 6 1. 07 91.3 <1 523 4. 5 .43 9. 34 798 310 2 27500 5.3 4. 24 542 464 3. 1 .595 135 <1 188 4. 3 .30 3. 78 858 289 a d i s s o l v e d metal i n ug/1 b p a r t i c u l a t e metal i n ug/1 c p a r t i c u l a t e metal i n ppm sediment d p a r t i c u l a t e Fe i n % sediment e HHA-extractable p a r t i c u l a t e metal i n ppm sediment f HHA-extractable Fe i n % sediment Table XIX: C o n d u c t i v i t y at lm depth, and d i s s o l v e d , t o t a l p a r t i c u l a t e , and HHA-extractable p a r t i c u l a t e metal concentrations i n the Fraser R i v e r . 00 84 also increase i n passing from fresh (<; 1 to. 1. lug/1) to brackish waters (2.6 to 5 .3ug / l ) . Thus t o t a l Z n ( Z n g plus Zn^) increases from less than 3.8ug/l to 8 .4ug/ l between s ta t ions 5 and 4, and remains at 7.8 and 7.7ug/l at s tat ions 3 and 2 r e spec t ive ly . Sim- i l a r l y t o t a l Cu increases from 3.4 to 4 .3ug/ l between stat ions 5 and 4, r e f l e c t i n g a change i n Cu^ from 2.2 to 2 . 7 u g / l , ' and a change in Cu from 1.2 to 1.6ug/l (71 to 95ppm dryweight). At the same time Fe and Mn remain constant, whi le , below s ta t ion 4, Fe . s s ' ' ' a decreases from 3ug/l to <-lug/l. Samples of the sa l ine wedge cont- ain 1.4ug/l Zn^, 2. lug/1 Cu^ (average) and <lug/l Fe^. HHA-extractable Zn leve l s (Table XIX) indica te that there i s a f i v e - f o l d increase of exchangeable and hydrous oxide-assoc- ia ted Zn in passing from fresh waters (average of 42ppm Zn g ) to brackish waters (more than 200ppm) with the greatest increase occ- urr ing between s tat ions 5 and 4. This increase (2 .7ug/ l ) appears to account for increase i n t o t a l suspended Zn (3 .0ug/ l ) . Changes i n Zn :Zn are from 20% i n fresh waters to 50% at s ta t ions 4 and e s 3, and to 86% at s t a t ion 2. Five percent of t o t a l suspended Fe and 25% of the Mn are also extracted from suspended sediments i n fresh waters, with a s l i g h t increase i n Fe :Fe and Mn :Mn ' e s e s between s ta t ions 5 and 4 (6.9 to 8.5% and 34 to 39% r e s p e c t i v e l y ) . Discussion Sorption and Desorption of Zinc Assuming an average concentration of 170ppm Zn for r iver-borne sediments, up to 50% and 70% of the t o t a l associated with suspended sediments at s tat ions 4 and 2 re spec t ive ly , might 85 have become associated with par t i cu la te s (sorbed) within the channel. This agrees we l l with changes in Zn :Zn (20% i n f resh- G S water to 50% at s t a t ion 4 and 86% at s t a t ion 2). The mechanism producing t h i s new assoc ia t ion i s not immediately obvious, espec- i a l l y considering the simultaneous increase i n d i s so lved Zn values. Sediment Zn and dis so lved Zn concentrations in the sa l ine wedge are low (above), suggesting that simple mixing with underlying sa l ine water i s not producing the observed e f fect s . Neither can sorption-desorption processes alone account for both increased par t i cu l a te and dis so lved Zn downstream of s t a t ion 5. However, assuming sorpt ion does occur, i f a mechanism existed whereby suspended sediments have a longer residence time in th i s region than fresh water, Zn could increase to a greater extent than predictable from t o t a l metal contents of the r i v e r water. A su i table mechanism may ex i s t , r e s u l t i n g from the t i d a l inf luence on r i v e r flow, and the s t r a t i f i e d flow system developed during in t rus ion of the s a l t wedge (p. 14) . For example, considerable amounts of sand are resuspended on ebb t ides i n the lower reaches of the r i v e r (Mil l iman, in press ) , and a small amount of s i l t - p l u s - c l a y was also observed to be resuspended. Deposit ion and resuspension w i l l increase the residence time of some p a r t i c l - es i n the channel. A further delay might be caused by the two- layer s t r a t i f i e d flow system, r e s u l t i n g i n a l ternate net seaward and landward movement of p a r t i c l e s t r a v e l l i n g f i r s t i n the surface layer and then i n the subsurface l ayer , although t h i s has not been demonstrated. The region between s tat ions 5 and 4 was the s i t e of ebb t ide resuspension of bed load at the time the study was 86 undertaken (Mi l l iman, i n press) and was l i k e l y near the upstream l i m i t of the sa l ine i n t r u s i o n . Presence of resuspended mater ia l i n sample 4 i s uncerta in . However, the s i m i l a r i t y of suspended sediment contents of the two samples ( F i g . 19) suggests the normal sedimentation rate upstream has been interrupted , perhaps imply- ing presence of p a r t i c l e s delayed i n t h e i r seaward transport . Sorption of metals by organic and inorganic p a r t i c l e s i n sa l ine waters has been demonstrated (Krauskopf, 1956; Kharkar et a l , 1968). Freshly p rec ip i t a t ed hydrous i ron oxide has been shown to be an e f fec t ive metal sorbant (Kharkar et a l , 1968), consistent with i t s metal scavenging a b i l i t y i n various environ- ments (Q. v . } Lee, 1975; Jenne, 1968). Since d i s so lved i ron i s removed from so lu t ion i n brackish water between s ta t ions 4 and 3, and since the newly sorbed Zn i s soluble i n HHA (adsorbed or incorporated i n hydrous oxides) , i t i s proposed that Zn i s scav- enged from so lu t ion by f reshly p rec ip i t a t ed hydrous i ron oxides. As p r e c i p i t a t i o n of these oxides l i k e l y takes place on suspended p a r t i c l e s (Aston and Chester, 1973), the combined ef fects of Zn scavenging and p a r t i c l e re tent ion i n the channel could account for great ly increased suspended Zn concentrations. The process probably occurs i n a r e l a t i v e l y narrow zone at the t r a n s i t i o n from fresh to brackish condi t ions , s ince fresh supplies of r i v e r - borne di s so lved Fe and Zn are required . Scavenged Zn i s probab- ly p r e f e r e n t i a l l y associated with f ine sediment f r ac t ions , as suspended Zn ( in ppm sediment) increases as sediment load decreases from s tat ions 4 to 2. 87 Removal of d i s so lved i ron i n other estuaries (Boyle et a l , 1974; Ho l l iday and L i s s , 1976; Coonley et a l , 1971; Bewers et a l , 1974; Lowman et a l , 1966) has been suggested as a factor in c o n t r o l l i n g trace metal behaviour i n coastal waters (Sholk- o v i t z , 1976; Eisma, 197 5; Aston and Chester, 1973; Lowman et a l , 1966) but data providing evidence for trace metal scavenging are scarce. B u r r e l l (1973) described the increase of sorbed Zn values on sediments settling through the ha loc l ine of an Alaskan f jo rd , and suggested coprec ip i t a t ion with i ron as a poss ible mechanism. P r e c i p i t a t i o n of trace metals and i ron i n f i l t e r e d Puerto Rican r i v e r waters mixed with f i l t e r e d sea waters was described by Lowman et, aJ. (1966), with the re su l t s used to explain i ron and trace metal d i s t r i b u t i o n s in nearshore sediments. A s i m i l a r experiment by Evans and Cutsha l l (1973) with Columbia River water produced no p r e c i p i t a t i o n of metals. Some authors have suggested that "d i s so lved" i ron ca r r i ed by r i v e r s i s already i n c o l l o i d a l form, and thus i t s apparent p r e c i p i t a t i o n i n estuaries i s due to coagulation of p a r t i c l e s which previous ly would pass through f i l t r a t i o n apparatus (Coonley e_t a l , 1971). This c o l l o i d a l phase probably contains trace metals, and i t s f l o c c u l a t i o n would therefore cause an apparent increase of p a r t i c u l a t e metal and decreased d i s so lved metal concentrations. This process could not, however, account for simultaneous increases.' in par t i cu la te z inc and dissolved z inc values as observed here. The same argument applies to coagulation of metal-complexing organic c o l l o i d s as an expl- anation for increased suspended z inc concentrations. 88 Increase i n d i s so lved z inc concentrations from s ta t ions 4 through 2 ( F i g . 19) i s consistent with reported des- orpt ion of metals from r i v e r sediments in sa l ine waters as desc- r ibed from f i e l d (Fukai et a l , 1975; Evans and C u t s h a l l , 1973; de Groot, 1973) and experimental studies (Murray and Murray, 1973; Kharkar e_t a l , 1968), inc lud ing work in Georgia S t r a i t (Thomas, 1975). Higher dissolved z inc values may thus represent desorption caused by s a l i n i t y increases r e s u l t i n g from mixing with under- l y i n g s a l ine water. A l te rna te ly upstream convection of brackish s u r f i c i a l Georgia S t r a i t water (Hodgins, 1974), which, r e s u l t i n g from desorption from suspended or bottom sediments at higher s a l i n i t i e s wi th in the S t r a i t , contains higher z inc concentrations than the r i v e r at t h i s time of year (Thomas, 1975), might produce increased dissolved z inc concentrations. Thomas observed maximum dissolved z inc values associated with water of s a l i n i t i e s of 25 to 28%0. This contrasts with a maximum desorption af 5%0 i n the Columbia River estuary (Evans and C u t s h a l l , 1971). Nevertheless, e i ther in brackish waters wi thin the channel, or at higher s a l i n - i t i e s i n Georgia S t r a i t , by some method z inc is mobil ized from suspended sediment. The mechanism of mobi l i za t ion i s not known. Thomas (1975) suggests that z inc (and copper) in exchange s i te s may be replaced by divalent magnesium and calcium ions i n sea water. Trace metal adsorption, however, involves a s p e c i f i c surface re- ac t ion , and not simple cat ion exchange (O'Connor and Kester, 1975), and thus desorption i s not a simple exchange process. The process i s further complicated by the fact that t r a n s i t i o n metals in 89 natural waters predominantly ex i s t not as divalent ions , but as ion pa i r s and complexes with various organic and inorganic ligands ( Z i r i n o and Yamamoto, 1972; Sylva, 1976), and thus adsorbed species w i l l be s i m i l a r l y complexed. Organic complexation may, however, a id desorption by increas ing the s o l u b i l i t y of metals in marine as compared with r i v e r i n e conditions (Duursma and Sevenhuy- sen, 1966; Rashid and Leonard, 1973). Complexation by organic chelators , c h i e f l y f u l v i c ac ids , has been postulated as the cause of apparent desorption from bottom sediments i n the Rhine and Ems estuaries (de Groot, 1973). Data of d i s so lved and p a r t i c u l a t e copper behave s i m i l - ar ly to those of z i n c , although trends are not nearly so wel l defined. Copper i s therefore be l ieved to undergo s i m i l a r sorp- t i o n and desorption processes, the l a t t e r process having been substantiated by Thomas (1975). Interpretat ion of manganese behaviour i s d i f f i c u l t without d i s so lved concentrations. Incre- ase i n Mn :Mn between s tat ions 5 and 4 suggests manganese i s e s adsorbed or coprec ip i ta ted with i r o n . P r e c i p i t a t i o n of hydrous manganese oxides would be expected to contribute to trace metal scavenging (Graham et a l , 1976; Jenne, 1968). Relat ive importance of the sorpt ion and desorption processes may be estimated approximately with data from t h i s study and that of Thomas (1975). Assuming sorpt ion of z inc occurs only between s ta t ions 5 and 4, suspended sediment i s capable of taking up 160 mg/kg z i n c , based on the increase i n HHA-extractable z inc between these two s t a t ions . Integrating records of mean discharge and suspended sediment load at Hope over the freshet period (May through July) of 1973 (Thomas, 1975), a freshet suspended sed i - 90 ment load of 11.7 x 10 kg was discharged, which was capable of 9 sorbing 1.9 x 10 g of z i n c . Thomas predict s freshet-desorbable 9 z inc to be 2 x 10 g, assuming 88ppm z inc i s removable from r i v e r suspended sediment (based on experimental data). This f igure i s probably high as re su l t s here suggest that the p o t e n t i a l for new dis so lved z inc must be less than 40ppm, the amount of HHA- extractable z inc i n r i v e r suspended sediments. To a f i r s t approximation, therefore, sorpt ion of z inc on suspended sediments occurs to at least twice the extent of desorption. Sorption probably occurs predominantly at low s a l i n i t i e s where i ron f i r s t p r e c i p i t a t e s , while desorption occurs over a range of s a l i n i t i e s . It i s impossible to estimate what port ion of desorbable z inc was o r i g i n a l l y sorbed onto suspended sediment in the estuary, without separating'adsorbed and Fe and Mn oxide-associated z inc from suspended samples of the channel and Georgia S t r a i t . It i s in te re s t ing to note, however, that metals adsorbed onto freshly p r e c i p i t a t e d hydrous i ron oxides were not desorbed extensively by sea water in experimental s tudies (Kharkar et a l , 1968). In general , previous studies have stressed the import- ance of e i ther trace metal sorpt ion or desorption, general ly the l a t t e r , as sediments enter the ocean. This study may be the f i r s t to describe occurrence of both. The apparent uniqueness of the s i t u a t i o n in the Fraser may be a t t r ibutab le to the f a i l u r e of other workers to consider a l l aspects of the problem. For example, considerat ion of d i ssolved concentrations alone w i l l not allow detect ion of more than one process, as in the case of Georgia S t r - a i t (Thomas, 1975), the Var estuary (Fukai et a l , 1975) and the 91 Columbia estuary (Evans and C u t s h a l l , 1973), where desorption has been described. Sampling of bottom sediments only led de Groot (1973) to postulate a desorption mechanism. Decreased metal values moving downstream in the t i d a l region of the Rhine may, however, be expl icab le by mixing of r i v e r bottom sediments and coastal sediments (Muller and Forstner , 1975), as observed i n the Elbe R iver . Various experimental 'techniques have also led to a r t i f i c i a l r e s u l t s . For example, r iver-bottom sediments have been used i n experimental studies to invest igate release of metals on mixing with sea water (Thomas, 1975; Johnson et a l , 1967). Results of these experiments must be interpreted cautiously for two reasons: i ) bottom sediments are not t y p i c a l of the t o t a l r i v e r sediment load; and i i ) fresh water sediments are far from being at equi l ibr ium with sea water, and any chemical reactions w i l l appear u n r e a l i s t i c a l l y rapid and extreme compared with natural mixing react ions . Thomas' (1975) estimation of 88ppm desorbable z i n c , for example, has been shown in th i s study to be an u n r e a l i s t i c a l l y high value for r i v e r suspended sediments. Even more a r t i f i c i a l re su l t s are obtained by mixing par t i cu la te s which have adsorbed metal from fresh water, with sea water (Kharker et a l , 1968; Murray and Murray, 1973). Resul t ing desorption i s not surpr i s ing considering how loosely bound are metals adsorbed i n th i s fashion. Furthermore both sorption and desorption i n these experiments w i l l occur in response to ambient metal concentrat- ions (O'Connor and Renn, 1964) and may r e f l e c t only achievement of equi l ibr ium between dis so lved and adsorbed metals. Moreover, 92 experimental procedures may not duplicate i n t e r a c t i o n of natura l organic mater ia l s , which affect both sorpt ion and desorption of metals (Murray and Meinke, 19,74; Sholkovi tz , 1976). In the case of the present study, a r e l a t i v e l y complete p ic ture of sorpt ion-desorpt ion processes a f fect ing z inc in the Fraser has been gained by considering data of both di s so lved and p a r t i c u l a t e phases of metal transport i n conjunction with phys ica l processes. Influence of Sorption-Desorption Processes on Trace Metal Content of Delta-Front Sediments Sorption of z inc in the hydrous oxide phase of susp- ended sediment i s very l i k e l y re f l ec ted in HHA-extractable z inc values i n de l ta- f ront sediments (Chapter IV) . The hydrous oxide- associated form of z inc i n s u r f i c i a l sediments comprises between 15 and 20% of t o t a l z inc values (Tables X and XII ) . It i s not poss ible to estimate prec i se ly how much of t h i s z inc r e f l e c t s Fe and. Mn . o x i d e scavenging i n the channel as opposed to scavenging in weathering and stream environments, as the degrees to which d i f ferent grain s i ze materials are affected by sorpt ion and desorption processes are not known. As the scavenging also involves copper, i t i s l i k e l y that some of the HHA-extractable copper in de l ta- f ront sediments f i r s t became associated with sediment in the main channel. This i s consistent with observed s i m i l a r behaviour of Zn, Cu and Pb i n experimental condit ions (Krauskopf, 1956), e spec i a l ly regarding t h e i r a f f i n i t y for adsorption to p a r t i c l e s , inc lud ing i ron and 93 manganese oxides. Lead, which occurs overwhelmingly i n HHA-ext- ractable form i n del ta- front sediments, i s therefore also be l ieved to be scavenged i n the channel, and lead contents of de l ta- f ront sediments are expected to r e f l e c t t h i s process. Manganese, as stated previous ly , may be p r e c i p i t a t e d (or coprecipi tated) as a hydrous oxide in the channel, and may be a scavenging agent for trace metals. P r e c i p i t a t i o n of mang- anese would have a small ef fect on HHA-extractable leve l s from suspended sediments, however, as th i s form of manganese i s already present on sediment in much greater amounts (Table XIX). There- fore, only a small f r ac t ion of manganese hydrous oxide i n de l t a - front sediments i s be l ieved to represent mater ia l p r e c i p i t a t e d i n the estuary. S i m i l a r l y , i ron hydrous oxide leve l s i n r i v e r suspended sediment are l i t t l e enhanced by p r e c i p i t a t i o n of fresh mater ia l i n the water column of the channel (Table XIX). HHA-extractable l eve l s of cobalt and n i c k e l are 15 to 20% and 10% respect ive ly of t o t a l values i n de l ta- f ront sediments. It i s not poss ible to estimate the amount of these metals scave- nged i n the estuary, although Gibbs' work on suspended sediments of the Yukon and Amazon Rivers (1973) suggests that r i v e r suspend- ed sediments contain high proportions of these metals (between 30 and 50% of t o t a l concentrations) i n as soc ia t ion with hydrous oxide coatings . The ef fect on these metals may therefore be f a i r l y minor. To ta l and MgC^-extractable metal l eve l s of de l ta- front sediments are expected to be inf luenced by desorption of metals. MgClg-extractable metals may be low as a resu l t of desorption of surface-sorbed metals from suspended sediments i n Georgia S t r a i t 94 or on the de l ta- f ront (Thomas 1975). The effect the combined processes have on t o t a l metal contents of de l ta- front sediments i s not pred ic tab le . Considering the high proport ion of l a t t i c e - bound metals in de l ta- f ront sediments, and the fact that sorp- t i o n and desorption are roughly comparable i n magnitude, the o v e r a l l ef fect on t o t a l metal deposit ion at the de l ta- f ront may not be great. The processes probably do, however, af fect the r e l a t i v e proportions of d i f ferent forms of metal deposited, tend- ing to increase the HHA-extractable metals and decrease the MgClg- extractable metals. As HHA-extractable metals are unavailable - for prediagenetic re lease , the effect may be temporary net removal of a port ion of b i o l o g i c a l l y ava i lab le metal from the environment. 95 CHAPTER VII : MECHANISMS OF TRACE METAL DEPOSITION IN NEARSHORE SEDIMENTS Introduction S i m i l a r i t y of trace metal contents of sediments of the Fraser de l ta- f ront and other nearshore regions (Table XII I ) , suggests common mechanisms affect metal depos i t ion . Some of these mechanisms may be applied to explain retent ion i n nearshore sediment of trace metals introduced by r ive r s and indus t r i e s . Discuss ion Trace Metal Deposit ion i n Nearshore Sediments Average t o t a l trace metal contents of unpolluted nearshore sediments low i n clay content are remarkably consistent (Table XII I ) . It follows that , ignoring f jords and other reduc- ing basins, mechanisms of trace metal deposit ion i n nearshore sediments probably do not d i f f e r great ly between d i f ferent reg- ions . Trace metal deposit ion on the Fraser de l ta- f ront can be b r i e f l y general ized on the basis of re su l t s of th i s study (Chapters IV, V and V I ) . The bulk of Co, Cu, Fe, Mn, Ni and Zn (but not Pb) are transported to the de l ta- f ront and deposited as constituent cations in c r y s t a l l i n e d e t r i t a l minerals . A further contr ibut ion of metals, inc lud ing Pb, i s present i n amorphous grain coatings of hydrous i ron and manganese oxides developed during weathering. This f r ac t ion i s enhanced by 96 metal scavenged in the estuarine port ion of the main channel by newly-formed hydrous i ron (and poss ibly manganese) oxides. A cer ta in amount of adsorbed metal i s mobil ized i n brackish water in the main channel and/or Georgia S t r a i t , and poss ib ly on the t i d a l f l a t s (Thomas, 1975). After b u r i a l , another small f r ac t ion of t o t a l metals may be mobi l ized. Occurrence of processes described here in other near- shore regions i s general ly confirmed in the l i t e r a t u r e . Near->! shore sediments are known to contain a greater proport ion of t h e i r trace metal content i n d e t r i t a l minerals than oceanic sediments (Chester and Messiha-Hanna, 1970) because sedimentation rates are highest i n nearshore regions. Importance of th i s f r ac t ion in f ine sediments from Los Angeles Harbour (Gupta and Chen, 1975) and Severn estuary (Chester and Stoner, 1975) i s demonstrated in Table XV. Fe and Mn oxide phases also contain s i g n i f i c a n t proportions of trace metals at these locat ions (Table XIV), although source of the oxides i n these cases was not inves t igated . Scavenging by hydrous i ron oxides, as described i n the Fraser estuary, has not been proven elsewhere, although i t has been suggested i n a number of instances ( q . v . , Lowman et al_, 1966; B u r r e l l , 1973). Loss of adsorbed metals has often been described ( q . v . , Fukai et a l , 1975; Evans and C u t s h a l l , 1973), and m o b i l i z - at ion of metals from buried sediments i s also a we l l known pheno- menon ( q . v . , Duchart e_t a l , 1973; E l d e r f i e l d and Hepworth, 1975). Other factors , e spec ia l ly organisms and organic matter, also great ly influence metal deposit ion in nearshore sediments ( q . v . , Schutz and Turekian, 1965; Rashid, 1974; Nissembaum and Swaine, 1976). Nonetheless, processes observed i n th i s study 95 appear to be major controls on trace metal deposit ion i n other nearshore regions. Trace Metal Sorption in Nearshore Waters Trace metals, l i k e a l l d i s solved constituents entering the oceans, have a f i n i t e residence time in the water column before they are deposited with sediment. Copper, for example, has a residence time of 50,000 years (Goldberg, 1965), a r e l a t - i v e l y short period compared with residence times of the major 8 7 cations sodium (2.6 x 10 years) and potassium (1.1 x 10 years ) . In the case of most trace metals residence times are not govern- ed by s o l u b i l i t i e s , as they are great ly undersaturated with respect to seawater (Krauskopf, 1956). Furthermore, seawater contains, on the average, smaller concentrations of d i s so lved metal than incoming r i v e r waters (Table XX). In other words, e f fec t ive mechanisms exi s t to remove trace metals from so lu t ion long before t h e i r concentrations become high enough to prec- i p i t a t e salts of the major anions. The most important of these mechanisms include : i ) adsorption onto c o l l o i d a l and f ine susp- ended p a r t i c l e s of c lay minerals , amorphous i ron and manganese oxides, and organic mater ia l ; i i ) coprec ip i t a t ion with hydrous i ron and manganese oxides; i i i ) p r e c i p i t a t i o n i n sulphide miner- a l s ; and iv ) incorporat ion i n l i v i n g organic matter and decay products (Goldberg, 1954, 1965; Krauskopf, 1956; Turekian, 1965, 1971; Nissembaum and Swaine, 1976). Krauskopf (1956) considered adsorption the most e f fec t ive mechanism c o n t r o l l i n g l eve l s of rare metals i n sea water. As the process depends on the presence of suspended p a r t i c l e s , i t occurs predominantly i n coasta l regions, e spec i a l ly Oceans Rivers Goldberg Rosier and Lange Durum and Ha f f t y Turekian Durum and H a f f t y Element (1965;Table I) - (1972;Table 97) (1963,Table 4) (1971;Table 2.6) (1963;Table 1) Co 0.1 ug/1 Cu 3 Fe 10 Mn 2 Ni 2 Pb .03 Zn 10 0.1 ug/1 1-90 . 2-20 1-10 , 1-.5 4-5 5-14 1-10 ug/1 .1-.5 3-4 5-10 •2 ug/1 .9-12 4- 12 0.3 2.3-3.9 5- 45 0-5.8ug/l(0)* 0.83-105(5.3) 31-1670(300) 0-185(20) 0-71(10) 0-55(4.0) 0-215(0) a median values b North American r i v e r s Table XX: Compilation of published summaries of trace metal concentrations i n ocean and r i v e r waters. CD oo 99 near r i v e r mouths (Chester, 1965). Coprec ip i t a t ion with hydrous i ron and manganese oxides has long been known as an e f f ec t ive scavenging mechanism for trace metals in oceanic basins with low sedimentation rates , and occurs during formation of manganese nodules (Goldberg, 1954). The process has also been suggested as a trace metal removal mechanism i n nearshore environments (Chapter V I ; Eisma, 1975; Sholkovi tz , 1976; B u r r e l l , 1973; Lowman et E i l , 1966). P r e c i p i t a t i o n of metal sulphides occurs l o c a l l y i n anoxic basins with r e s t r i c t e d c i r c u l a t i o n , as commonly exis t in coasta l i n l e t s and basins . Uptake of metals by organisms and organic mater ia l i s greatest i n areas of highest p r o d u c t i v i t y , that i s , i n nearsurface waters, e spec ia l ly near cont inenta l marg- ins . In l i g h t of these mechanisms, i t i s probable that r iver-borne metals are predominantly removed from so lu t ion i n nearshore waters (Chester, 1965). This furthermore implies t h e i r deposi t ion near to t h e i r point of input to the oceans. Turekian (1971) goes so far as to say that most r iver-borne metal does not leave the es tuar ies , being removed by organisms, and u l t i m - ately f ixed as sulphides i n the sediment. While removal by organisms i s not the only e f f ec t ive process, h i s o v e r a l l conc l - usion i s probably v a l i d . Given the wide range of condit ions both wi th in and between es tuar ies , understanding of t h i s port ion of metal cycles w i l l be a complex problem. No doubt so lut ions to the problem w i l l vary between d i f ferent geographic l o c a l i t i e s . Examples of such d i s p a r i t y are already common i n the l i t e r a t u r e . Iron, for example, has been shown to act conservat ively i n some estuaries 100 (Eisma, 1975) while behaving in a nonconservative manner i n others (Boyle et a l , 1 9 7 4 ; Coonley et_ al, 1 9 7 1 ; Lowman e_t a l , 1966 ; Bewers et al_, 1 9 7 4 ) . Z inc , while d i sp lay ing nonconser- vat ive behaviour in the Fraser estuary (Chapter VI ; Thomas, 1975) and the Columbia estuary (Evans and C u t s h a l l , 1973) behaves con- serva t ive ly i n the Beaulieu estuary (Hol l iday and L i s s , 1 9 7 6 ) . Moreover the s a l i n i t i e s over which chemical changes occur appear to d i f f e r between d i f ferent l o c a l i t i e s . Maximum z inc desorption, for example, was described at 5%oin the Columbia estuary (Evans and C u t s h a l l , 1973) but at 25 to 28%oin Georgia S t r a i t (Thomas, 1 9 7 5 ) . Another source of incons i s tencies in metal behaviour i n estuaries involves differences i n pH contrast between r i v e r and marine waters. Increasing pH, as usual ly found i n estuarine t r a n s i t i o n , favours adsorption of metals (Murray and Murray, 1 9 7 3 ) , countering the desorption effect pre- d ic ted during increas ing s a l i n i t y at constant pH (O'Connor and Kester, 1 9 7 5 ) . Another even more obvious var iable i s the r e l a - t i v e metal content of r i v e r and coastal waters. In the case of an Alaskan f jord ( B u r r e l l , 1973) sediment s e t t l e s through a sharp ha loc l ine into water of greater d i s so lved z inc concentrat ion, and i n response sorbs z inc from s o l u t i o n . B i o l o g i c a l uptake (q.y. , Turekian, 1 9 7 1 ) , organic complexation (q .v . ,Ra sh id and Leonard, 1973) and phys ica l processes (Chapter VI) also influence the net behaviour of a metal being introduced to the marine environment. Removal of Waste Trace Metals to Nearshore Sediments Trace metals of i n d u s t r i a l and urban o r i g i n discharged into r i v e r s and nearshore waters may be at least temporarily 101 removed from the water- column by sorpt ion processes. Results of th i s study (Chapter VI) suggest some estuaries have a cer ta in capacity to sorb di s so lved metals and thus render them unavailable to marine organisms. Removal of waste metals to sediment has been observed in the Back River estuary (Helz et al.,- 1975), and experimental addit ion of metals to s a l t marsh ponds was almost a l l accounted for by enrichment of metals in sediment (Duke et a_l, 1966). Metal sorpt ion capacity w i l l be surpassed at cer ta in leve l s of contamination, i n which case trace metals w i l l be transported to deeper waters and/or ingested by marine organisms. Even metal removed to sediments, however, i s not permanently inacces s ib le . P o s t - b u r i a l mob i l i z a t ion , in combination with current a c t i v i t y or dredging operations, w i l l reintroduce dissolved metals to the water column (Duincker et a l , 1974; E l d e r f i e l d and Hepworth, 1975). 102 CHAPTER V I I I : CONCLUSIONS AND SUGGESTIONS FOR FURTHER RESEARCH Summary of Conclusions (1) Trace metal contents of Fraser de l ta- f ront sediments are t y p i c a l of other nearshore unpolluted sediments. They display an inverse r e l a t i o n with sediment grain s i ze , as comm- only observed elsewhere. (2) Trace metals in de l ta- f ront sediments reside l a rge ly within l a t t i c e s i t e s of d e t r i t a l minerals , with a s izeable f r ac t ion bound in amorphous hydrous oxides of Fe and Mn. Pb i s an exception to t h i s r u l e , being extracted almost exc lus ive ly with the l a t t e r phase. Adsorbed metals (excepting Mn) are i n s i g - n i f i c a n t over the de l ta- f ront as a whole, except i n the region affected by discharge of primary treated sewage from Iona Island. This region displays t o t a l contents of Cu, Pb and Zn which are anomalous. (3) Trace metal p r o f i l e s of short cores are general ly un i f - orm, except in those cores containing tex tura l v a r i a t i o n s . App- arent loss of some metals at depth may r e f l e c t pos t-depos i t ional mobi l izat ion, assuming metal input rates to the de l ta- f ront have been constant over the time represented within the cores. This assumption i s suspect, as at least one area (near Iona Island) contains a nearsurface t r a n s i t i o n i n metal concentrations re la ted to urban a c t i v i t i e s . ' (4) Scavenging of d i ssolved z inc from the water column by newly formed i ron (and poss ib ly manganese) hydrous oxide coatings occurs in brackish waters of the main channel. This sorpt ion 103 process probably accounts for a f r ac t ion of trace metal contents, e spec ia l ly Cu, Pb and Zn, of de l ta- f ront sediments. Desorption of Zn also takes place i n the channel or Georgia S t r a i t , but to a somewhat lesser extent than the sorpt ion process. (5) . Processes s i m i l a r to those described here probably affect trace metal deposit ion i n other nearshore sediments. Sorption processes p a r t i a l l y account for re tent ion of d i ssolved metals, inc lud ing contaminant metals, in nearshore sediments. Suggestions for Further Research A d d i t i o n a l research projects suggested by re su l t s of t h i s study include: (a) extension of sediment sample c o l l e c t i o n and analys i s to deeper port ions of the de l ta- f ront and Georgia S t r a i t ; (b) charac ter iza t ion and determination of metal content of the organic f r ac t ion of f ine-gra ined sediments, e spec ia l ly in areas rece iv ing sewage discharge/ (c) c o l l e c t i o n of longer cores in regions of continuous deposi- t i o n , app l i ca t ion of a su i tab le dating technique to determine sedimentation rates , and analysis of extractable and t o t a l metals of sediments, and dis so lved and complexed metals wi th in i n t e r - s t i t i a l waters; (d) r i v e r water and suspended sediment sampling at d i f ferent times of year, over t i d a l cycles and at several depths, and analys is for extractable and t o t a l p a r t i c u l a t e , and complexed and t o t a l d i ssolved metal; and (e) c o l l e c t i o n and analysis of water and suspended sediments 104 wi th in the plume and at surface and bottom depths over the de l ta - f ront . 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Introduction to B i o s t a t i s - t i c s . Freeman and C o . , San Franci sco , 368p. 113 APPENDICES APPEND!X A CO, CU, F E m , MN, N I , PB AND ZN CONTFNT (PPM) OF FRASER DELTA-FRONT SEDIMENTS SERIES A INTERTIDAL SAMPLES I FEBRUARY 1974) CO CU FE MM NI PB ZN 9.94 14.12 1.52 272.19 38.36 3.07 41.31 9.98 14.98 1.64 299.89 42.90 4.24 43.18 13.26 30.95 2.29 323.94 46.24 9.18 63.48 11.37 22.74 2.38 236.40 41.56 3.95 62.07 11.09 16.49 1.81 313.11 39.78 4.87 50.07 10.23 22.21 1.66 305.81 45.98 1.31 39.41 11.72 12.38 1.81 315.68 47.95 1.31 40.80 8.71 12.41 1.49 287.94 36.39 2.82 38.79 10.39 13.05 1.83 282.50 47.22 0.94 42.32 10.66 14.40 1.86 303.75 38.86 2.44 47.65 11.68 16.13 2.08 298.93 41.61 3.73 52.04 10.70 16.22 2.10 359.85 38.41 3.89 56.02 13.40 13.75 2.25 320.35 58.60 4.43 54.22 10.64 13.72 1.39 307.63 40.15 5.35 46.85 10.31 15.09 1.72 295.09 43.78 3.20 45.72 10.33 12.20 1.68 290.68 43.78 0.0 42.17 8.32 11.94 1.53 269.17 38.96 0.0 38.85 14.62 10.51 2.36 320.72 77.25 0.25 51.28 8.57 10.44 1.75 199.71 33.92 1.66 44.98 12.15 16.05 2.08 232.50 41.38 2.10 57.39 11.37 16.44 2.12 243.91 40.95 3.29 59.79 12.97 30.72 2.37 307.67 47.91 7.99 79.75 15.17 40.50 2.45 364.56 53.91 9.48 76.19 11.25 14.37 1.86 335.87 54.86 2.23 46.30 14.28 36.28 2.53 342.70 50.79 62.91 72.28 10.40 16.53 1.72 457.18 42.77 2.04 47.08 12.22 22.86 2.06 411.60 44.22 6.79 57.02 10.76 14.83 1.71 436.93 39.70 3.68 46.36 11.90 17.59 1.89 365.45 41.68 4.75 50.92 11.44 16.13 1.71 403.63 41.27 3.82 50.59 12.99 27.83 2.31 340.83 45.59 8.41 64.61 9.23 16.68 1.63 273-78 37.10 2.67 43.95 14.08 12.27 2.13 355.39 62.81 3.91 53.43 9.84 12.40 1.58 286.55 39.55 2.72 45.41 9.70 13.29 1.57 298.37 37.76 3.06 43.33 12.43 13.32 1.86 358.94 57-68 0.0 50.06 12.74 12.55 1.82 325.18 49.71 1.25 47.21 11.06 11.79 1.73 276.02 45.08 3.22 44.34 13.77 12.40 2.00 318.98 59.99 3.61 50.42 12.72 12.52 2.01 311.50 53.68 3.14 48.57 10.84 14.28 1.69 296.16 41.06 3.33 48.83 12.72 13.79 1.89 318.13 48.71 5.04 53-10 10.71 13.88 1.66 247.23 37.05 5.01 47.60 STN E N 1 124 61 2 136 62 3 149 59 4 148 49 5 134 45 6 124 50 7 111 49 8 111 37 9 123 37 LO 137 38 11 150 37 12 162 37 13 151 26 14 136 26 15 123 25 16 112 25 17 95 35 18 162 13 19 165 22 20 174 24 21 174 36 22 159 49 23 73 43 25 123 88 26 121 94 27 111 100 28 111 88 29 105 73 30 120 73 31 110 62 32 95 80 33 85 87 34 85 75 35 85 56 36 101 56 37 72 76 38 74 101 39 83 117 40 81 127 41 80 140 42 79 153 43 79 166 44 82 182 SSL I ?S AND 1.1 96-9 2.1 94.2 3.9 34.0 3.2 50.0 2.7 80.3 1.6 95.3 1.7 96. 1 1.0 94.8 1.3 98.2 1-5 88.6 2.5 67.5 3.9 67.5 1.9 94.2 1.7 94. 7 1.1 92.3 1.1 96. 8 0-7 96. 1 0. 8 95.5 2.2 95.3 3.1 76.5 3.2 65.8 2.8 30.4 2.6 8.3 0.0 94.9 2.2 22.9 1.0 92.4 1.6 80.7 0.8 92.6 1.2 85.9 1.1 84.5 2.7 62.1 1.4 95.0 0.0 96.9 0. 1 95.3 1.4 96.0 1.4 95.1 1.4 95.9 1.2 94.2 1.9 88.9 1.6 95.6 1.4 86.4 1.3 94. 8 1.4 95.5 114 45 86 199 10.43 13.18 46 89 209 10. 35 14. 11 47 99 199 10.47 13.03 48 99 186 9.71 14.56 49 112 192 11.38 24.46 50 123 117 11.57 21.46 51 124 131 11. 00 19. 23 52 123 145 12.48 22.77 53 121 156 1 2. 07 23.16 54 118 184 10.03 42.65 55 111 175 15.04 47.16 56 111 162 10. 31 14. 53 57 111 150 12. 59 23.99 58 111 137 11.30 13.17 59 111 125 12. 47 18.44 60 95 116 11.84 11.41 61 86 138 10. 22 12. 38 62 86 150 9.36 11.35 63 85 162 10.50 13.06 64 86 175 12.31 13. 12 65 98 175 9.57 12.65 66 99 161 10.16 12.53 67 98 150 10.32 13.09 68 98 138 9.31 12.00 69 99 124 8. 8 8 10.69 1.60 232.05 35.84 1.64 522.35 40.59 1.69 283.08 37.48 1.76 339.00 30.15 2.11 285. 85 41.00* 2.07 290.83 38.55 1.85 291.07 37.76 1.97 285.61 40.42 1.95 312.89 39.77 1.59 193.68 34.67 2.45 375.09 47.57 1.54 284.46 37.19 2.19 3 41.5 9 41.14 1.58 343.83 38.33 1.86 367.25 42.38 1.64 321.90 53.15 1.53 280.08 39.43 1.51 239.11 39.29 1.64 276.19 39.91 2.02 366.74 49.80 1.47 286.71 32.00 1.71 267.82 42.98 1.66 273.84 40.57 1.64 251.02 38.14 1.57 247.48 41.80 4.32 47.01 2. 2 96. 3 0.0 47.57 1.51 49.15 1. 9 94.7 9.31 51 .68 1. 9 92.7 10.81 67.58 3. 2 54.1 5.66 63.72 3. 6 31.3 5.63 60.60 1. 9 62. 1 5. 75 62.85 2. 5 48.6 10.83 64.90 2. 5 60. 6 38. 88 83.40 3. 0 67.2 29. 13 94.82 5. 6 52.3 3.11 50.48 2. 0 91.7 8.55 70. 38 3. 0 58.0 5.92 50.44 2. 0 93.4 6. 50 60.11 2. 8 81.9 1. 76 48.62 0. 4 96. 7 3.37 46.94 4. 01 45.27 1. 5 97.9 4.83 56.22 1. 3 91.2 4. 39 53.79 4. 55 45.76 2. 0 94. 8 2.49 47 .99 0.7 94.1 3. 00 47-66 1. 1 98.5 5.30 47.20 0. 6 96. 7 2.92 43.67 1. 2 95.4 SERIES B FORE-SLOPE SAMPLES (MARCH 1974) STN E N CO CU FE 1 61 94 12.63 35.10 2.51 2 54 94 11. 88 28. 97 2.23 3 49 94 12.42 37.35. 2.37 4 49 100 12.94 36.22 2.74 5 54 100 12.65 37. 27 2. 51 6 61 100 13.21 36.02 2.69 7 64 100 11. 84 27.77 2.38 8 67 100 14.00 31.37 2.39 9 67 106 14.33 40.74 3.15 10 .61 106 14.47 38. 16 2.52 11 54 106 13.39 37.90 2.52 12 36 1 00 12.81 36.41 2.35 13 23 113 13.17 36.22 2.75 14 23 126 13.55 38.27 3.25 15 36 126 13.04 39.24 3.10 16 36 113 14.03 38.81 2.75 17 49 113 12.77 38.67 2.17 18 54 113 1 2. 89 40.49 2.39 19 61 113 13.09 40.22 2.43 20 67 113 14. 03 41. 11 2.81 21 70 113 14. 56 38.19 3.24 22 73 113 11. 73 11.45 1.91 23 73 119 12.07 18.41 2.01 24 70 119 13.97 39.89 2.23 25 67 119 14.40 40.45 2.92 26 61 119 13.98 43. 59 2.75 27 49 126 14.69 41.98 2.56 28 61 126 14.40 42.83 3.20 29 67 126 15.38 42.35 3.35 MN NI PB ZN %l\ %SAND 359.98 48.40 18.74 76.49 4.5 40.5 414.48 50.86 15.31 69.98 3.7 57.6 325.85 46.68 15.54 90.78 7.2 30.5 312.48 46.18 9.85 77.73 5.6 22.5 319.80 47.13 17.03 79.69 5.1 37.1 338.72 48.91 12.41 78.47 4.2 33.8 324.88 44.55 10.36 69.52 2.3 35.0 331.95 47. 79 7. 71 71.52 2.8 33.4 393.35 51.17 11.45 89.05 5.7 18.1 343.42 50.24 16.32 76.63 6.1 26.9 352.16 48.76 13.41 83.56 5.3 30.0 279.56 47.76 8.00 74.70 5.2 24.8 331.95 46.35 7.27 85.63 5.0 19.9 404.92 46.50 14.19 99.26 4.8 16.6 331.55 48.83 8.66 97.60 4.2 13.6 293.57 44.47 8.30 78.07 3.9 20.3 285.70 50.79 10.52 75.52 4.4 27.4 340.11 50.99 15.69 77.07 5.6 25.7 349.16 50.32 22.82113.89 5.8 25.0 426.60 51.27 17.85 94.29 5.2 19.0 360.32 51.22 11.45 87.35 3.3 19.6 255.31 44.82 3.13 50.72 1.0 96.6 253.20 43.85 "7.33 68.02 0.4 72.8 243.53 51.95 14.63 75.75 3.2 18.3 350.90 49.94 14.90 85.87 4.9 18.4 393.31 51.02 13.48 92.09 6.0 18.6 356.66 50.32 10.44 84.12 6.7 13.3 366.02 49.94 9.07 92.37 6.0 10.5 380.65 50.14 13.79 92.37 5.0 15.2 115 30 70 126 15. 04 41. 71 31 73 126 13.70 30.24 32 73 132 13. 22 31. 08 33 70 132 14.92 41.29 34 67 132 15.27 43.05 35 61 132 15.21 42.79 36 49 138 14.58 42.63 37 61 138 14.40 42. 54 38 67 138 14.35 39.25 39 70 138 15.64 40.82 40 73 138 14.30 25.22 41 73 144 11.54 24.43 42 70 144 14.10 38. 35 43 67 144 1 3. 86 40.60 44 61 144 14.62 41.46 45 49 150 13. 76 41. 66 46 61 150 12.44 42.15 47 67 150 12.15 42.45 48 70 150 11.67 37.9). 49 73 150 10.67 14.73 50 73 157 9.65 11. 19 51 70 157 13.90 33.22 52 67 157 14.40 40.28 53 61 157 13. 54 43.41 54 49 163 15.74 42.33 55 61 163 14. 72 41.46 56 67 163 11.83 36.06 57 70 163 11.61 25.89 58 73 163 11.31 10. 18 59 73 169 11.09 14.12 60 70 169 14.65 33. 90 61 67 169 .15.95 42. 26 62 61 169 16. 55 45.93 63 49 176 16.78 44.44 64 61 176 17. 12 42.91 65 67 176 15.30 42.68 66 70 176 15.62 40.30 67 73 176 13.37 23.27 68 73 182 14.00 16.72 69 70 182 15.45 35.37 71 61 182 1 6.42 4 5. 28 72 49 188 16.59 44.40 73 61 188 16.48 44. 89 74 67 188 16.23 43.38 75 70 188 15.47 40.91 76 73 188 14.38 21.10 77 80 188 11.98 10.95 78 80 194 12.95 10.79 79 73 194 14.44 28.04 80 70 194 16.93 43.50 81 67 194 1 6.77 45.11 82 49 200 15.39 47.02 83 61 200 16.31 46.44 84 67 200 16. 15 44. 80 85 73 200 15.21 35. 14 86 80 200 13.43 12.85 87 80 207 12. 86 30.76 88 76 207 12.77 17.66 89 73 207 13.65 34. 99 90 67 207 16.21 46.70 2.95 408.98 49.09 2.34 301.17 47.01 2.06 278.14 46.91 2.72 347.54 52.54 2.98 382.46 52.73 3.31 381.94 53.90 3.08 380.65 55.79 3.01 405.23 54.35 2.92 456.51 52.74 2 .98 400.'+5 51.87 2.22 294.33 45.37 2.19 299.45 45.02 2.77 397.62 49.87 2.95 386.14 53.15 3.01 386.54 52.13 3.14 432.90 50.55 2.94 420.38 51.77 2.82 366.23 55.39 2.61 375.08 51.06 1.74 244.53 40.91 1.54 252.97 41.13 2.32 327.77 47.10 2.72 356.70 52.56 2.91 368.04 54.80 2.78 388.53 56.95 2.85 401.93 48.37 2.54 350.07 46.48 2.03 282.77 40.70 2.28 313.67 49.47 1.30 236.24 39.47 2.37 320.43 46.24 2.66 365.66 50.36 2.92 406.88 50.98 2.88 421.86 51.57 2.95 396.54 50.56 2.82 389.37 49.54 2.64 348.38 48.74 2.10 267.45 43.36 1.94 254. 55 42. 59 2.41 341.86 45.41 2.98 416.52 51.96 3.08 430.16 50.38 3.13 423.79 51.67 2.94 391.49 52.35 2.65 369.13 49.31 2.16 282.41 46.11 1.66 261.66 38. 70 1.73 253.54 40.72 2.28 233.69 45.23 2.90 376.65 49.59 2.88 403.97 51.36 3.27 512- 50 50.51 2.95 427.47 49.96 2.95 379.29 53.51 2.47 315.41 47.20 1.91 257.24 43.54 2.36 303.63 42.65 2.04 257.80 42.45 2.59 324.41 44.45 3.19 421.53 53.43 11.74 93.01 5.6 19.7 3.16 72.45 5. 1 45.6 9.82 72.19 1.7 55.8 10.84 91.06 4.0 19.9 13.53 91.97 5. 5 14.0 12.46 98.26 5.2 10.8 13.15102.56 5.6 10.4 6.01 96.79 5.6 9.1 18. 24 92 .26 4.9 15.9 15.17 94.25 3.3 16. 7 11.31 68.93 1.1 59.5 9.75 65.51 1.0 54.7 13.02 87.85 4.0 22.4 16.11103.42 6.0 16.2 14.99102.79 6.2 9. 2 16.25111.20 6.9 9.9 15.57110.68 5. 8 12.0 14.47108 .79 3.8 15.2 14.90 91.46 2.8 29.2 5.11 52.30 1.5 84.4 3.09 48.59 2.7 96.5 14.17 80.89 4.4 41.5 13.38 99.83 5.2 21.2 13.77100.99 6.2 11.5 15.89110.47 6.1 8.6 15.60131.52 4.9 17. 1 14.24 92.33 3.4 25. 7 9.29 71.93 3.1 52.0 4.34 52.30 2.0 98.9 5.83 55.46 3.3 86.4 12.19 81.67 4.1 40.0 13.27 99.70 5.2 19.5 14.55108.86 7.2 8.2 14.27111.56 . 7.1 8.2 14.15104.08 5.3 9.7 14.59 98.05 3.4 15.9 14.60 86.94 3.0 19.6 6.54 62.96 2.4 65. 5 5.61 57.32 1.4 82.4 16.89 88.13 3.8 35.2 16.96112.64 6.4 7.6 16.72109.29 7.5 0.6 17.71105.72 5.3 3.8 16.66 98.62 4.1 6.1 16.15 94.61 13.0 12.0 8.93 61.43 1.7 50.4 5.45 45.06 1.2 79.2 6.61 47.34 1.1 59.9 10.05 68.80 2.5 26.5 16.44 96.49 4.6 5.4 16.08 99.91 4.9 4.4 22. 34111 .93 6.6 0.8 18.03106.89 5.3 5. 7 15.50102.48 3.7 0.0 11.09 82.81 4.5 22.2 3.59 53.10 2.1 57.4 11.09 75.53 3.8 31.4 5.35 55.11 1.7 49.5 12.25 82.58 2.5 12. 1 17.29109.02 3.4 7.3 91 61 213 16.63 45.99 3.15 414.00 53.03 20.49110.34 5.7 3.9 92 67 213 15.65 47.27 3.20 387.30 53.32 18.87106.38 5.5 8.7 93 73 213 13.67 33.35 2.45 311.66 45.71 12.27 80.02 3.4 17.7 94 76 213 13.71 29.16 2.28 263.92 44.38 10.43 72.32 3.1 29.4 95 80 213 14.46 21.12 2.73 312.75 53.21 6.12 66.77 2.4 4 8 . 0 96 80 219 13.51 16.96 2.20 274.56 48.08 6.49 60.30 1.8 50.8 97 76 219 13.24 26.83 2.31 303.75 44.71 11.57 98.80 2.5 33.4 98 73 219 14.16 36.88 2.53 322.09 47.41 13.11 85.24 2.4 16.7 99 67 219 15.63 48.35 3.03 457.82 50.91 23.13113.44, 4.8 8.4 100 61 225 15.31 47.39 3.05 389.42 53.67 23.46113.48 6.3 7.5 101 67 225 14.93 44.51 2.83 364.13 52.18 16.28 98.96 5.2 10.2 102 73 225 13.47 33.79 2.55 323.40 48.25 15.35 87.34 4.3 2 0 . 0 103 80 225 11.28 10.23 1.68 243.32 41.43 3.25 42.90 0.8 56.0 104 86 232 9.98 12.56 1.49 222.61 33.86 5.24 40.93 1.4 63.5 105 86 238 12.42 28.36 2.11 231.76 40.59 14.43 76.75 2.2 19.8 106 80 232 11.32 13.53 1.54 226.70 36.52 3.24 40.50 0.8 83.1 107 73 232 13.43 29.02 2.23 299.01 41.48 12.02 72.50 2.2 32.5 108 67 232 13.68 40.68 2.63 396.60 47.21 21.11 90.68 3.9 18.2 109 80 238 10.69 23.15 1.86 255.89 38.83 10.74 66.97 2.8 43.5 110 73 238 12.38 31.63 2.16 284.65 39.90 14.03 72.31 3.7 32.6 111 67 238 14.77 45.40 2.75 371.63 55.42 20.75102.50 5.3 13.9 112 61 232 15.34 47.04 2.79 401.92 47.82 25.27109.05 6.3 22.2 113 61 238 14.52 50.46 2.94 375.63 47.31 32.44115.32 5.6 11.0 114 49 238 14.95 48.97 2.99 423.86 46.67 35.78122.09 5.4 7.5 115 61 2.44 3.5.19 61.48 2.99 499. 28 43.32 43. 39124.43 4.2 9.4 116 67 244 16.64 49.82 2.34 323.64 34.88 19.65 97.83 4.6 14.5 117 73 244 14.03 37.49 2.33 305.99 41.95 16.96 84.32 4.0 2 2 . 0 118 80 244 14.40 36.33 2.39 310.64 45.20 13.71 84.92 4.3 18.9 119 86 244 12.94 34.54 2.18 303.02 41.90 12.86 80.94 3.7 22.8 120 92 250 13.04 32.29 2.09 279.58 40.72 13.31 75.17 3.4 29.7 121 86 250 13.68 41.32 2.61 321.46 47.21 15.24 91.65 5.3 13.8 122 81 250 13.53 47.39 2.49 332.18 44.95 23.05 97.38 3.6 17.6 123 73 250 13.53 45.66 2.61 324.44 44.25 20.50 90.71 2.1 14.4 124 67 250 15.07 60.91 2.74 420.95 42.89 48.77131.76 2.8 12.5 125 61 250 14.77 53.98 2.56 408.36 41.57 33.41108.00 5.3 16.1 126 67 257 15.40 55.46 2.88 356.52 50.97 26.72113.98 5.5 10.4 127 73 257 14.74 50.88 2.45 344.21 47.55 22.76106.17 4.4 15.1 128 80 257 14.74 45.90 2.34 304.02 43.71 21.45 91.39 4.7 12.0 129 86 257 14.77 53.08 2.74 354.59 50.31 25.80106.09 5.8 8.0 130 92 257 13.49 44.45 2.60 335.33 41.31 21.83 94.06 3.9 10.5 131 , 92 263 16.19 61.68 2.42 321.58 46.86 22.12 96.35 2.5 4.5 132 86 263 15.87 62.10 3.00 374.29 48.89 36.53125.50 3.6 4.0 133 162 6 12.15 11.38 2.00 255.72 50.04 1.88 60.15 10.9 6 0 . 0 134 155 6 13.51 28.13 2.49 291.00 47.48 5.40 83.05 3.2 14.3 135 155 12 11.36 11.27 1.67 240.13 43.76 2.95 52.11 1.6 68.9 136 148 6 15.50 23.56 2.44 291.95 53.52 5.28 72.74 8.3 34.4 137 143 6 12.81 12.60 2.11 275.34 51.52 1.28 57.02 1.3 62.4 138 143 12 16.45 11.04 2.56 329.55 79.21 1.78 69.62 1.2 64.5 139 143 18 13.10 17.56 1.99 269.72 45.98 3.22 61.24 0.9 41.9 140 136 18 14.81 15.46 2.23 295.56 58.29 4.55 62.15 0.5 55.7 141 136 12 13.99 17.09 2.00 282.42 54.03 2.26 46.66 0.6 83.3 142 136 6 15.27 11.70 2.14 301.11 62.54 2.33 47.74 0.5 98.7 143 130 6 12.00 11.66 1.51 247.72 43.25 1.83 40.77 1.0 97.8 144 130 12 10.57 13.38 1.54 264.60 43.39" 1.75 44.29 1.8 93.4 145 130 18 14.78 13.27 2.02 319.85 64.93 1.77 54.49 1.4 93.6 146 123 18 13.94 23.29 1.94 310.33 51.61 4.61 61.51 2.5 64.8 147 123 12 12.06 13.09 1.77 295.29 53.97 3.02 49.94 0.4 97.7 148 123 6 12.78 14.03 1.79 297.24 52.72 3.72 51.42 0.3 8 8 . 1 149 117 6 13.01 15.69 2.10 327.46 56.68 3.79 62.63 1.1 84.7 150 117 12 13.12 11.99 1.90 323.53 65.13 2.19 49.70 0.8 97.3 151 152 153 154 155 156 157 158 1 59 1.60 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 207 208 209 210 211 117 111 111 111 93 98 86 73 98 104 110 108 105 105 98 98 92 86 73 61 80 86 92 95 92 89 86 80 73 67 61 67 73 80 83 86 80 77 73 67 61 54 48 54 61 67 70 73 67 64 61 54 48 48 54 64 61 57 54 48 18 18 12 6 6 12 12 12 18 18 24 24 24 31 31 24 24 24 24 24 31 31 31 31 3 7 37 37 37 37 37 37 44 44 44 44 44 50 50 50 50 50 50 50 56 56 56 56 56 62 62 62 62 62 68 63 68 75 75 75 75 12. 70 12.48 14.13 13.22 11.81 12. 50 11.36 11.27 11.87 15.86 12.84 11.35 13.41 14.97 15.51 11.93 10.92 10.38 12.02 10.60 10.12 3.69 9.45 10.71 11.81 9.70 10.85 10.99 12.26 11.30 11.37 1 1.44 10.98 11.84 9. .6 0 13.20 12.74 12.56 12.65 13.02 12.33 11.07 11.91 11.98 12. 21 10.61 12.65 15. 37 12.17 11. 47 11.65 14.12 12.35 13.04 10.34 12.18 13.63 11.40 11.81 12.07 17.29 11.50 13.46 11.28 17. 88 17.44 20. 20 25.59 12. 84 12. 56 23.18 13. 35 22.43 32.01 33.60 12.56 10. 71 10.34 21.84 22.34 11.94 11.35 12.60 13.95 12.53 12.17 12. 03 14.47 20.88 20.96 21.37 19.99 18.27 17.17 11.63 23.04 17.78 22.07 20.37 26. 26 27.09 26.65 26.79 21.39 20. 83 17. 87 13.10 23.91 12.57 18. 66 22.52 30.71 28.21 29.47 22. 11 16.20 21.76 24.08 26.01 27. 64 2 .03 1.73 1.99 2.06 2.13 2.08 99 31 82 30 09 1. 73 2.27 2.28 2.44 1.94 1.66 1.65 2.10 2.13 1.50 1.32 1.54 1.71 1.82 1.52 1.51 1.69 2.04 1.93 2.14 1.98 81 85 1.51 2.09 2.00 2.05 2.01 2.16 2.15 2.24 2.23 2.10 1.96 1.80 2.12 2.28 1.78 1. 83 2.01 2.33 2.25 2.28 1.81 1.83 2.16 1.91 2.05 2. 14 280.64 272.24 310.92 320.21 289.92 319.14 273.58 294.25 2 74.92 3 54. 9 2 337.31 235.04 335.02 367.38 349.19 2 86.6 6 269.67 266.16 265.48 3 04. 7 2 222.66 212.32 247.81 265.36 328.54 2 51. 2 5 238.25 258.61 281.34 275.48 287.58 282.49 268. 19 233.88 261.64 320.64 290.85 292.01 297.50 302.66 302.78 305.02 345.08 294.11 307.74 270.80 301.84 334.60 297.73 288.88 295.04 344.46 335.71 377.61 307.15 315.97 347.26 301.42 344.16 337.76 52.93 57.01 71.52 66.75 48. 16 50.32 41.27 38. 62 49. 14 73. 58 48.08 52.07 54.62 54.98 53.15 51.02 45 .74 44.92 42.02 36.47 37.30 36.79 40.02 43.12 53.85 40.59 36.64 39.92 41.51 39.67 36. 86 39.32 39.08 45.97 41.07 47.96 45 .60 47.38 48.68 46.00 45.09 40.43 38.57 42.56 42.29 41.94 54.47 56.38 49.35 44 .06 43.36 48 .22 45.12 46.97 44. 34 46. 09 49.82 43. 12 47. 12 44.89 3.43 2. 60 1. 78 2.29 9.31 4.67 5.57 9.13 2. 97 1. 91 6.50 4. 85 6. 66 6.61 5. 83 1.35 2.18 0. 93 5. 86 8. 86 2.90 2.07 2.34 2. 89 2. 54 2.60 1.53 4.22 5.23 11.25 7.31 4.96 2. 69 2.61 1.41 4. 70 3.29 3.03 3.75 4.73 5. 14 10.56 10.00 7.68 6.30 2.04 3.76 3.39 0.0 3.24 4. 57 9.44 8.03 8.08 3.73 5. 4R 6.42 8.00 8.60 8.05 57.39 47.64 50.51 59 .73 68.95 63.88 67.01 80.90 53 .50 55.06 66.68 61.65 72.67 85 .76 77.54 50.96 44.82 44.59 71 .69 82 .06 46.39 39 .80 45.56 48.41 49.33 47.13 42 .04 49.46 64.10 69.14 74.49 62.67 60.34 54.49 41 .90 62.21 61 .47 62.38 61.93 67.27 76.37 79.20 77.22 64.98 61.82 51.97 54.99 70.09 47.54 53.54 59.85 76.74 81 .05 81.05 58 .70 52.24 59.94 57.70 65.66 70.10 2.8 0.9 0.8 0.9 1.9 1.5 2.5 4.9 L.9 1.0 2.7 1.6 2.7 2.2 3.0 1.0 0.8 0.8 3.0 5.3 1.6 1.2 1.5 1.4 1.4 1.5 2.0 1.6 2.4 2.5 3.0 2.9 2.1 2.1 2.0 3.3 1.5 1.6 2.1 2.5 4.0 5.1 4.9 4.0 3.0 0.6 1.9 1.4 1.6 2.3 2.3 4.3 4.9 3.3 3.0 2.2 3.3 6.2 4.6 89.1 98.8 96.8 98.4 73.9 76.8 68.5 52. 1 90.8 98.3 71. 5 96.4 75.5 42.3 40.2 94. 7 97. 1 95.9 62.8 51.7 95.4 99.0 97.9 95.3 98.3 98.3 95.5 91.9 70.2 63.4 55.9 70.3 80.4 79.6 99.0 74.3 81.4 73.2 72.0 58.5 52.6 47.7 45.2 68.9 77.2 87.8 69.3 97.1 87.0 76.2 45.9 40.5 4 1 . 5 78.1 86. 9 77.0 77.0 76.2 58.3 118 212 36 75 10.68 22.63 213 36 88 13.70 36.20 214 48 88 13.19 32.51 215 48 81 11.70 29.89 216 54 81 11.28 27. 44 217 57 81 12.60 29. 16 218 61 81 10.00 16. 86 219 54 88 11.72 21. 84 220 61 88 12.09 28.23 1.77 290.59 45.31 2.49 355.87 49.90 2.35 376. 19 46. 51 2.16 326.31 46.06 2.04 318.60 47.10 2.19 329.46 47.84 1.67 288.39 43.73 1.95 394.28 53.02 2.01 333.11 49.50 4. 16 53.96 2. 9 80.6 8. 12 85.72 3. 0 24.4 11. 62 92.08 4. 0 40.2 8. 52 75.13 4. 2 51.3 9. 15 65.24 3. 6 68.8 8. 19 70.68 4. 1 61.2 3. 54 44.45 2. 1 98.0 6. 47 55.79 2. 2 82.0 12.32 63.27 3. 1 67.4 SERIES C TNTERTTD4L SAMPLES (APR!L 1974) CO CU FE MN NI PB ZN 15.08 35.75 2.81 420.89 55.76 8.68 93.21 13.88 29.01 2.43 438.90 52.44 8.57 80.76 16.92 14.48 2.24 405.14 70.68 4.18 55.82 12.92 14.81 1.75 3 76.19 50.30 3.40 49.36 11.79 16.27 1.78 369.40 47.19 3.49 45.89 10.83 14.24 1.81 328.25 49.28 2.05 42.15 15.88 34.47 2.30 420.58 54.93 8.28 72.46 12.59 13.93 1.85 323.48 58.14 1.99 44.49 13.26 20.23 2.05 441.71 47.36 6.03 58.96 17.16 38.66 2.90 571.80 64.23 9.47 90.13 15.32 27.25 2.37 439-37 57.65 6.45 71.96 16.73 15.27 2.11 456.78 73.08 1.72 53.89 10.10 12.07 1.65 274.24 41.27 2.32 43.56 10.62 12.52 1.64 308.04 40.47 4.34 45.78 12.96 19.27 2.05 323.00 44.71 4.29 59.34 11.01 14.78 1.92 305.25 41.29 5.09 56.66 11.01 20.03 1.88 318.38 41.74 3.84 57.27 12.22 13.22 1.92 255.57 39.86 6.16 51.00 13.36 11.39 1.83 297.27 38.96 1.64 55.82 12.41 17.36 2.11 248.18 41.31 2.31 60.87 10.26 8.68 1.58 240.43 40.61 2.45 45.29 11.16 12.65 1.62 286.18 40.89 3.49 42.85 12.04 12.26 1.64 312.84 47.04 2.27 43.59 13.45 12.73 1.93 379.43 60.18 1.94 48.05 12.46 12.07 1.70 316.14 50.93 2.24 43.59 12.41 11.43 1.77 317.31 49.16 2.40 43.75 18.43 12.43 2.35 432.63 98.70 0.0 54.18 13.14 12.00 1.98 356.95 61.40 0.0 47.25 14.00 10.93 2.14 368.83 62.10 0.0 52.04 14.36 20.07 2.27 423.72 56.05 2.00 65.05 15.39 12.49 2.06 454.27 73.71 0.0 53.66 11.98 12.71 1.69 406.31 43.11 0.0 48.04 13.41 14.68 1.89 375.17 56.80 1.04 47.28 10.29 11.56 1.39 322.10 42.29 1.48 38.98 12.66 11.41 1.79 349.29 58.83 2.06 46.16 12.08 14.29 1.81 340.92 47.52 3.59 49.36 19.09 38.02 2.93 519.68 70.95 7.41 92.92 13.33 14.93 1.70 498.42 52.81 4.19 54.37 16.64 42.90 2.73 439.30 59.94 17.53105.87 14.00 26.59 2.22 417.45 49.45 9.19 75.80 13.96 14.76 1.69 363.61 41.49 5.40 57.91 13.69 27.57 2.15 394.05 45.49 7.59 75.28 11.03 11.79 1.34 362.14 28.22 4.81 45.04 13.00 11.86 1.65 329.15 40.00 5.35 51.52 13.83 14.90 1.65 408.98 47.22 5.63 54.03. STN c N 1 159 43 149 50 3 137 50 4 124 50 5 124 62 6 137 62 7 148 59 8 133 73 9 124 75 10 124 88 11 122 94 12 111 100 13 124 38 14 136 36 15 149 37 16 162 37 17 151 26 18 162 25 19 174 37 20 175 25 21 162 12 22 131 28 23 125 24 24 108 40 25 97 38 26 86 46 27 '72 65 28 76 77 29 86 75 30 86 91 31 98 87 32 99 73 33 99 64 34 102 49 35 111 49 36 111 62 37 114 77 38 110 87 39 121 1 56 40 123 145 41 125 131 42 124 117 43 111 125 44 112 137 45 111 149 46 111 162 10.72 12.90 1.40 47 111 175 13.02 14. 2 7 1.75 48 118 133 14.4 7 73.05 2.44 49 90 209 11.13 15. 20 1.70 50 99 1.98 12.05 14.25 1.89 51 112 191 12.65 30.77 2.31 52 99 174 12.93 14.84 1.81 53 99 160 13.47 12.92 1.95 54 99 150 12.36 13. 65 1.63 55 99 137 12. 50 13.11 1.73 56 99 124 12.60 12.40 1.89 57 96 1 16 14.94 12.50 2.00 58 74 100 13.31 16.20 1.83 59 86 162 12. 69 13. 72 1.64 60 87 174 14.34 14.36 1 . 94 61 83 182 11.82 12.31 1.69 62 86 198 12.56 13. 62 1.77 63 99 186 14.32 16.05 1.84 64 81 166 15.72 16.60 2.06 65 79 153 13.47 13. 04 1.79 66 83 1 16 15.01 12.51 2.04 67 92 131 12.65 11.28 1.78 68 89 138 11.91 12.45 1.59 69 87 150 12.58 12.11 1.68 286.12 39.98 2.84 45.33 330. 82 39.19 9. 79 56.33 285.25 43.38 41-22109.24 383.35 33.62 4.94 49.56 237. 42 34. 74. 8. 11 51.94 308.60 36.46 15.94 74.17 297. 15 33.04 10. 06 53.55 305.14 45.45 4.08 49.66 303.29 36.02 5.34 48.29 265.80 35.07 2.14 46.04 320.32 42.50 2.48 49.13 371.41 48. 12 3.13 51 .37 360.82 37.62 5.42 50.34 295.56 32.28 8.47 47.65 487.24 41.76 4.94 53.77 272.91 36.56 5.23 47.37 278.38 35.07 4.58 47.72 423.29 36.15 5.49 51.55 552.00 43.91 7.34 55.82 367.69 39.69 8.34 47.90 319.20 52.78 2.71 49.42 287.90 43.00 3-70 45.34 257.82 35.79 3.89 45.06 267.69 42.20 4.01 46.09 SERIES D INTERTIDAL SAMPLES TN p N CO CU FE 1 174 37 13. 55 10. 04 1.80 2 174 25 12.93 15. 33 2.03 3 162 3 7 11. 27 12. 97 1. 93 4 159 49 13.98 26.49 2.73 5 149 50 15.05 25.11 2.46 6 148 59 13. 79 17.88 1.93 7 137 62 14.58 31.01 2.26 8 136 50 16.92 32. 79 2.72 9 149 38 12.32 14.23 1.87 10 151 26 13.48 24.21 2.20 11 161 25 10.57 11.40 1.86 12 161 12 13.32 9.57 1.79 13 180 12 12. 43 17.06 2.40 14 181 7 8.72 7.33 1.34 15 123 24 13.88 13.72 1.93 16 98 37 16. 76 12.89 2.26 17 86 46 13.52 13.67 1.60 1 8 86 62 16. 69 28. 39 2.35 19 86 75 15.87 17. 31 2.07 20 72 76 18.87 41.75 2.99 21 86 88 14.34 14.90 1.69 22 99 73 16.29 20.79 2.13 23 98 62 16.89 18.96 1.99 24 99 50 18.62 23. 58 2.04 25 111 37 14.56 15.00 1.71 26 123 37 14. 00 13. 33 1.73 27 131 27 15.00 14.76 1.82 28 136 37 15.43 19. 59 2.13 29 123 50 17.21 16. 06 2.3 4 30 111 50 16.14 14.34 2.09 ( MAY 1974) MN NI PB ZN 265.22 35.86 3.39 51.82 243.51 40.99 4.79 56.88 272.78 37.85 7.77 51.47 305.42 45.04 6.22 75.23 456.00 52.42 5.75 68.76 356.67 56.35 3.02 48.24 461.15 49.07 4.07 66.19 467.22 53.53 4.97 75.80 289. 55 37.30 3. 10 51.90 384.29 41.05 1.02 62.18 230. 87 31.47 3. 54 47.44 257.03 46.87 2.57 46.19 245.23 43.26 5.61 62.30 182.62 28.80 4.20 35.10 312.34 46.77 1.93 48.21 3 77. 71 62.06 1. 14 48.52 294.28 35.97 4.81 44.29 425.05 46.63 4.24 66.38 416. 18 57. 57 0. 77 52.39 528.28 56.88 5.14 83.17 302.46 44.59 3.07 43.79 430.24 51.35 5.61 57.10 581.70 50.44 2.14 54.71 771.67 55.53 . 4.16 58.81 341.79 44.07 3.41 46.90 327.51 44.01 1.52 43.96 304.30 44.82 7.19 47.67 373.21 45.74 5.70 56.88 426.12 63.68 3.49 54.93 382.06 53.88 4.83 50.49 31 110 62 32 98 87 33 111 190 34 97 185 35 98 174 36 117 183 37 111 174 38 99 160 39 86 161 40 80 155 41 86 149 42 86 137 43 86 124 44 81 115 45 74 100 46 87 174 47 82 181 48 86 197 49 89 209 50 99 197 51 111 100 52 110 87 53 112 77 54 124 62 55 131 69 56 124 75 57 124 87 58 121 94 59 96 116 60 99 123 61 98 13 62 98 149 63 111 161 64 111 149 65 111 136 66 111 124 67 123 117 68 124 131 69 122 144 70 121 155 17.51 13.26 2.29 379.77 67.13 2.66 51.10 20.41 35.70 2.69 712.31 60.00 7.70 79.78 15.94 38.34 2.73 358.28 48.97 16.51 85.71 13.05 14.27 1.77 309.12 39.30 9.02 50.92 13.22 14.39 1.92 332.84 41.45 5.95 52.17 16.39 86.68 2.97 337.95 51.71 50.69126.49 18.79 20.55 2.24 356.58 44.47 14.81 65.60 15.60 13.26 2.12 322.22 44.68 4.52 51.52 21.84 25.40 2.06 1016.71 54.78 7.54 64.52 15.43 12.84 1.78 293.29 42.10 4.43 47.14 15.41 13.14 1.87 334.11 46.29 7.25 47.42 14.10 13.08 1.87 369.74 55.80 4.10 48.78 15.33 14.55 2.03 491.73 57.93 4.13 50.67 14.14 14.10 1.97 397.94 55.01 3.91 50.35 13.39 17.04 1.92 379.84 43.70 2.51 54.26 12.22 13.92 1.96 357.51 44.88 5.50 53.52 14.66 14.33 1.84 532.73 52.99 4.43 54.29 12.71 13.20 1.77 274.22 44.89 4.95 49.41 10.05 13.76 1.68 531.46 39.80 2.82 46.50 11.02 13.38 1.66 295.76 38.58 7.23 48.89 10.63 14.80 1.66 447.38 45.27 3.12 44.64 13.52 33.60 2.64 454.34 53.53 7.30 72.63 13.54 30.82 2.63 441.47 51.79 6.62 71.92 11.18 13.60 1.82 292.13 49.59 3.80 41.16 16.48 44.35 3.14 575.62 61.30 9.52 87.68 12.82 18.05 2.01 505.08 48.23 4.02 56.39 14.70 40.37 2.78 548.20 57.41 9.39 80.19 10.51 21.75 2.05 383.05 44.72 5.41 55.64 10.38 13.48 1.33 376.51 47.67 4.58 50.07 13.88 12.27 2.27 430.09 62.24 4.10 52.17 10.14 11.59 1.58 321.59 37.56 4.76 46.70 3.0.63 11.80 1.66 321.72 41.40 3. 88 45.57 9.25 12.80 1.51 252.75 38.07 4.10 41.94 12.90 20.31 2.23 339.91 44.56 8.01 63.49 11.03 15.62 1.82 344.99 42.61 7.31 52.78 9.81 10.04 1.26 292.18 29.50 4.37 37.93 14.84 30.51 2.49 292.18 51.88 7.02 75.87 13.04 29.76 2.37 344.99 45.70 9.07 73.40 16.15 37.95 2.88 443.56 56.98 14.80 90.72 13.07 34.97 2.53 369.63 48.02 12.83 80.00 SERIES E INTERTIDAL SAMPLES I JUNE 1974) TN E N CO CU FE MN NI PB ZN 1 118 183 16.04 72.60 3 .19 389.59 57 .14 35.84120.29 2 111 174 12.20 14.63 1 .92 296.58 39 .83 9. 97 57.92 3 99 174 11.12 11.79 1 .61 274.33 35 .12 6. 22 45.66 4 87 174 11. 50 12. 12 1 .80 260.79 41 .29 4. 74 49 .49 5 86 161 11.07 10. 97 1 .92 279.81 46. 58 2.3 1 46.56 6 102 162 10.21 11.32 1 .69 267.48 42 .63 3.23 44.26 7 111 161 11.22 12. 65 1 . 78 350.35 42 .85 5.23 50.45 8 121 155 12.80 30.37 2 .58 408.79 46 .96 15. 60 83.41 9 111 149 10.59 11.46 1 .70 357.90 38 .10 6.67 51 .29 10 98 149 11.09 14.91 1 .91 317.54 42 . 55 4. 13 54.26 11 86 149 12.58 12.90 1 .98 355.16 51 .83 4.53 50.68 12 86 137 13.18 16. 33 1 . 89 690.05 51 .41 6.54 55.19 13 86 124 12.88 12.40 1 .89 351.65 54 .00 4.15 48.19 14 94 115 10.86 10.15 1 .66 306.38 39 .54 6.17 45.32 15 99 123 16 98 137 17 111 137 18 123 144 19 121 130 20 121 103 21 111 124 22 111 1 90 2 3 99 198 24 97 184 25 111 100 26 111 87 27 98 36 28 86 87 29 87 75 30 72 77 31 85 46 32 98 37 33 99 50 34 98 62 35 86 62 36 96 74 37 114 76 38 110 62 39 111 49 40 111 37 41 123 24 42 136 25 43 151 26 44 123 37 45 136 36 46 149 37 47 162 37 48 159 49 49 122 94 50 124 87 51 132 69 52 136 62 53 148 59 54 149 50 55 136 50 56 161 25 57 174 37 58 174 24 59 164 12 60 180 12 61 181 7 62 124 50 63 124 62 64 124 75 9.41 8.99 10.44 11. 50 10. 88 12.64 11.19 9.16 11.34 11.15 9.62 14.84 16.91 9.90 13. 46 14.28 10.87 13.89 13.95 10.72 12.85 12.64 13.33 14.34 11.49 9.79 10.60 11.03 13.10 10.66 10.90 11.23 10.04 12.38 16.85 10.32 13.20 11.31 15.12 11.80 10.47 9.87 11.03 10.47 10.69 7.78 7.04 9. 08 7.44 11.80 11.09 10.76 11.27 13.07 13. 62 24. 63 14.30 15.74 11.92 13. 83 20. 22 22.60 25.71 15.67 12. 95 14.49 13.14 12.62 30.70 15. 55 13.16 26.76 15.35 23.18 11.66 12.77 13.35 15. 10 26.62 13.63 12.92 14.85 12. 84 26. 61 42.04 15.12 29.40 23. 12 38. 57 24.66 13.27 12.05 12. 53 13.40 8.90 8. 73 7.95 16.00 15.62 22.32 1.34 1.68 1. 80 1.81 1.89 2.49 1.54 1.81 1.88 1.69 1.85 2.16 2.22 1.65 1.95 2.03 1.75 2.03 2.44 1.79 2.00 2.18 1.9 8 2.26 1.75 67 63 88 32 66 1.65 1.75 1.78 2.51 3.15 1.75 2.26 1.95 2.87 2.47 1.69 2.03 2.01 85 89 56 38 74 42 1.82 208.64 222.28 319. 53 268.07 342.09 438.76 298.83 234.47 262.92 492. 17 332.68 453.06 604.76 277.35 361.09 392.11 310.63 343.00 360.03 2 87.06 370.42 416.89 527.79 435.29 330.37 286.21 268.59 2 64.75 301.65 317.25 279.59 262.25 343.40 279.23 629.50 281.54 417.38 3 50.4 8 577.47 326.43 3 70.0 7 242.89 225.09 205.96 248.93 174.07 166.43 253.46 2 56. 98 408.36 37. 83 35.24 38.63 35.36 37.68 44. 33 39.89 35. 87 41.20 37.60 47.64 53.24 52.84 37.47 52.51 62.2 9 42.26 61.93 50. 13 42.77 53. 91 46.96 57.21 59. 40 48.79 41.60 37.95 40.24 46. 59 41. 28 36.00 37.38 34.65 45.40 60.14 42. 51 46.51 44.76 56.91 45.53 43: 99 38.50 36 .12 36. 20 42.34 28.35 27.88 44 .65 37.08 43.15 2. 56 4.45 7.00 6.40 8.27 8. 07 4.45 9.05 4. 82 8.92 2.88 4. 69 4.27 2.21 2.43 0. 79 2.89 1. 64 3.2 8 1.75 1.2 3 5.53 3.41 4. 86 3.06 3. 75 4. 17 6.56 7. 52 2.62 5.12 6.39 3.64 6.26 9.93 C. 92 3.97 3.62 6. 98 4.74 0. 47 3.38 3.86 3.04 1.83 3.18 1. 58 0.0 0. 0 0.0 41.19 42 .13 49.22 53.52 55.35 72.53 41.83 52.43 46.79 50.43 48.15 55 .87 61 .25 42.03 46 .50 46.90 44.72 43. 74 71.03 46 .79 50.39 60.87 51.61 59.87 43.05 43.09 42.75 49.58 69.19 41 .95 42.60 47-75 44.76 67.29 87.51 40.13 63.02 51 .03 78.81 68.83 45.21 51.48 58 .77 53 .06 49 .46 47.83 40.60 41.23 37.93 49.48 SERIES F INTERTIDAL SAMPLES (OCTOBER 1974) STN E N CO CU FE MN NI P 8 ZN 1 159 48 15.69 36.75 2.93 315.15 55.33 12.76 79.25 2 148 49 14.19 24.50 2.15 262.62 49.49 7.59 56.76 3 136 50 12.20 12.97 1.41 424.24 42.52 0.0 42.83 4 125 49 12.55 11.53 1.52 290.90 49.90 0.0 39.62 5 112 49 12.20 6 107 74 12.73 7 111 88 12.84 8 111 100 10.60 9 124 74 12. 20 10 124 61 16.23 11 149 37 9.93 12 168 30 12.13 13 117 156 12-66 14 117 145 12.45 15 118 132 13.66 16 118 121 13.44 17 111 123 9.05 18 111 135 1 0.25 19 112 150 11.14 20 112 162 11.63 21 88 175 15. 52 22 85 162 12.89 23 80 167 24.48 24 79 153 10.52 25 86 150 12.02 26 86 138 10. 97 27 86 124 10.80 28 83 117 15.04 29 99 175 11.91 30 99 161 11.70 31 99 150 11.25 32 99 138 10.93 33 99 124 10.73 34 95 116 11.95 35 74 100 13.95 36 72 76 12.37 3 7 86 75 13.95 38 99 72 11.32 39 99 64 10. 83 40 100 50 11.00 41 111 37 9.6 5 42 123 37 12.47 43 137 37 9.89 44 152 27 8.43 45 99 87 11.20 46 86 87 11.50 11.89 1.64 307.07 11. 53 1.48 375. 75 16.57 1.96 371.71 12. 25 1.64 2 70. 70 13.33 1.68 331.31 10.81 1.84 375.75 7.92 1.56 2 02.02 13.69 1.96 270.70 16.21 2.03 307.07 14.41 1.72 274.74 23.42 2.19 347.47 23.06 2.27 404.04 10.81 1.64 234.34 10.09 1.64 294.94 10.81 1.76 307.07 10.45 1.76 262.62 11.53 2.23 379.79 14.96 1.64 361.00 32.73 1.88 1922.74 11.40 1.48 235.43 12.11 1.52 294.29 11.40 1.56 266.83 9.26 1.56 235.43 10.63 1.84 282.52 8.90 1.37 255.05 9.62 1.48 274.67 9.97 1.41 266.83 10.33 1.41 255.05 10.33 1.37 251.13 9.26 1.64 282.52 11.40 1.84 313.91 11.40 1.76 302.14 10.69 1.80 333.53 16.74 1.76 443.40 12.47 1.64 282.52 13.89 1.72 333.53 11.75 1.48 266.33 14.25 1.92 232.52 12.90 1.52 263.12 10.03 1.32 247.64 15.40 1.76 355.98 11.46 1.93 282.46 49. 62 0. 0 44.98 33. 83 8.30 44.98 44. 98 0.0 50.33 43 . 23 0.0 46.05 38. 31 0.0 46.05 55. 56 0.0 49.26 34. 80 0.0 46.05 45. 02 0. 0 53.54 44. 49 13.21 55.68 38. 44 7. 23 49.26 46. 42 10. 70 66.39 42. 48 0.0 63.18 35. 59 3. 54 41.76 35. 85 6.63 47.12 39. 11 3. 70 46.05 37. 21 5. 06 49.26 52. 90 3.42 53.54 40. 67 4.36 47.27 67. 62 6.45 71.43 41. 20 1. 24 42.02 40. 62 0.0 45.17 4 2 . 83 0.0 44.12 40. 18 0. 0 40.97 54. 81 0.0 46.22 35. 80 0.0 40.97 43. 05 0.0 40.97 39. 30 0.0 42.02 37.37 0. 0 42.02 35. 15 0.0 40.97 47.83 0.0 43.07 56. 45 0. 0 48.32 52. 48 0.0 44.12 54. 90 0. 0 45.17 40. 98 0.0 49.37 43. 72 0.0 42.02 42. 61 0. 0 46.22 38. 51 0.0 42.02 44.17 0. 0 49.37 34. 77 0.0 39.73 29.85 0.0 36.60 42. 92 0.0 43.92 56. 90 0. 0 41 .83 SERIES G FORE-SLOPE SAMPLES (OCTOBER-NOVEMBER 1974) STN N CO CU FF MN NI PB ZN 1 61 94 11. 50 30. 81 2.29 2 90.20 43.85 0.0 66.92 6 61 100 12.22 31.53 2.33 309.55 46.19 0. 0 67.97 7 64 100 9.99 15.76 2.01 259.25 48 .73 0.0 44.96 20 67 113 14.10 39.41 3.05 3 55. 98 51.42 7. 49 87.84 21 70 113 14.07 37.62 2.93 355.98 49.13 12.14 83.66 22 73 1 13 13.08 33. 68 2.73 317.29 50.03 0.0 73.20 30 70 126 13.57 37.98 2.89 340.50 51.60 5. 49 86.79 31 73 126 10.19 12.54 2.01 247.64 40.95 0.0 43.92 39 70 138 14.63 40.13 2.81 297.94 50. 84 8. 79 86.79 40 73 138 9. OR 10.75 1.40 212.81 36.37 0.0 39.73 55 61 163 13. 08 40. 13 3.01 321. 16 50.57 13.66 92.02 56 67 163 9.96 32.25 2.49 278.59 45. 75 8. 13 71 . 11 57 70 163 11.20 58 73 163 9.14 64 61 176 14.23 65 67 176 13. 57 66 70 176 12.09 67 73 176 9. 88 72 49 188 13.75 73 61 188 13.27 74 67 183 15. 89 75 70 188 13.03 76 73 188 12.62 77 ao 138 9.75 82 49 2 00 14.72 83 61 200 15. 82 84 6 7 200 14.40 85 73 200 11.42 86 GO 200 9.37 91 61 213 13.27 92 67 213 14. 13 93 7 3 213 11.79 • 94 76 213 10.91 95 80 213 11.52 96 80 219 10.56 97 76 219 11.90 98 73 219 11.83 99 67 219 14.44 104 06 232 10.63 105 86 238 14.52 1 06 SO 232 9. 54 107 73 232 11.92 108 67 232 13.65 109 80 238 13.65 117 73 2 44 11.72 118 80 244 11.82 119 86 244 11.72 120 92 250 12.32 123 73 2 50 12.78 124 67 250 13.82 126 67 257 14.38 130 92 257 12.32 131 92 263 14.22 132 86 263 12.98 133 162 6 8.81 134 155 6 8.65 135 155 12 11.09 136 148 6 10.56 137 143 12 14.12 138 143 12 17.90 139 143 18 13.67 140 136 18 13. 54 141 136 12 11.89 142 136 6 15. 54 143 130 6 9.86 144 130 12 9.86 145 130 18 13.45 149 117 6 10.21 150 117 12 12.15 151 117 18 10.08 152 111 18 7.03 153 111 12 17.20 31.53 2.41 278.59 11.82 1.88 247.64 43.00 3.05 317.29 33.70 3.01 321.16 35.11 2.61 278.59 9.08 1.40 190.45 41.04 3.19 376.93 42.86 3.19 333.29 43.58 3.11 349.16 34.50 2.60 293.61 30.14 2.53 269.80 11.62 1.63 218.22 49.03 3.03 329.32 45.76 3.19 357.09 45.40 3.19 365.03 33.78 2.60 301.55 11.62 1.83 226.16 43.58 2.92 333.29 44.31 3.11 333.29 33.41 2.45 269.80 26.15 2.21 249.96 18.16 2.41 257.90 22.52 2.14 253.93 22.52 2.14 249.96 30.87 2.41 269.80 45.76 3.11 333.29 13.01 1.57 205.68 40.36 2.67 304.57 15.49 1.53 217.55 30.27 2.28 261.06 40.36 2.95 308.52 34.23 2.51 276.88 31.71 2.36 268.97 30.99 2.28 261.06 26.30 2.32 253.15 34.95 2.55 268.97 41.80 2.95 344.12 51.89 3.14 403.46 58.37 2.99 316.44 43.24 2.67 292.70 52.97 3.14 332.26 54.05 2.99 324.35 15.13 1.69 193.82 9.73 1.77 253.15 14.41 2.04 229.41 10.81 1.85 245.24 10.09 2.36 268.97 34.51 2.95 324.00 12.75 2.24 236.33 19.50 2.44 240.14 13.13 2.63 243.95 20.63 3.30 289.69 11.25 2.16 217.27 10.12 2.51 278.26 32.26 2.95 339.24 11.25 2.44 274.44 15.00 2.67 304.94 48.76 2.48 289.69 10.12 2.04 259.20 24. 76 2.99 2 85.88 44.51 10.21 71.11 45.57 0.0 43.92 50.52 13.90 92.02 52.82 8.20 87.84 50.61 * 9.69 77.38 30.95 0.0 38.71 50.25 14.91101.07 54.59 12.99 96.77 54.28 16.39 98.92 45. 96 9. 76 80.64 45.49 5.41 70.96 35.82 4.01 43.01 47.41 35.47133.33 52.72 16.19103.22 54.90 14.28 98.92 48.44 7.97 79.57 39.78 0.0 45.16 52.89 13.94101.07 50.60 11.88100.00 43.71 11.52 75.26 41.05 2.53 64.51 49.13 0.0 55.91 41.42 0.0 59.14 42.44 0.0 60.21 42.23 0.0 73.11 49.82 11.65 98.92 35.95 0.0 51 .20 52.71 13.48 88.53 38.20 0.0 44.80 44.50 12.05 72.53 50.77 14.35 90.66 45.80 8.91 74.66 45.58 6.79 78.93 42.69 11.95 74.66 42. 77 7. 98 73.60 47.14 12.82 78.93 50.51 15.82 98.13 49.32 37.39109.86 52.58 59.25109.86 43.89 15.13 91.73 51.78 22.50104.53 51.91 25.39106.66 39.39 0.0 44.30 47.45 0.0 40.53 50.24 3.67 53.33 47.10 0.0 42.66 67.88 0.0 42.66 54.90 6.08 79.37 47.07 0.0 45.95 41.77 0.0 55.97 50.33 0.0 46.78 53.05 0.0 66.84 39.01 0.0 40.10 52.96 0.0 48.46 46.72 0.0 72.68 50.20 0.0 50.13 56.98 0.0 55.97 51.34 0.0 55.97 46.11 0.0 41.77 54.68 0.0 73.52 124 154 111 6 14.76 156 98 12 13. 67 157 86 12 10.77 159 98 18 11.63 161 110 24 15.24 163 105 24 14.19 165 98 31 13.45 166 98 24 12.63 167 92 24 9.12 168 86 24 7.14 171 80 31 9.53 172 86 31 7.37 173 92 31 9.61 174 95 31 9.23 175 92 3 7 3.49 176 89 37 9.87 177 86 37 9. 76 178 80 37 9.08 179 73 37 10.40 180 67 37 9.68 1 81 61 37 8.37 182 67 44 10.40 183 73 44 10.13 184 80 44 13.00 185 83 44 9. 05 186 86 44 9.72 187 80 50 13.75 188 77 50 11.67 189 73 50 11.67 190 67 50 14. 34 191 61 50 11.73 192 54 50 12.28 194 54 56 12.69 195 61 56 11.63 196 67 56 13. 06 197 70 56 12.50 198 73 56 13.31 199 67 62 11.83 200 64 62 11.70 201 61 62 12.58 202 54 62 12.98 203 48 62 10.13 204 48 68 12.80 205 54 68 12.69 2 06 61 68 12.54 207 64 63 10.97 2 08 61 75 10.31 209 57 75 12.98 210 54 75 12.76 211 48 75 12.37 212 36 75 13.11 213 36 88 12.86 214 48 88 11.25 215 48 81 12.05 216 54 81 12.09 217 57 81 11.14 218 61 81 9.36 219 54 88 11.91 220 61 88 10.65 25.13 3.07 289.69 23.25 2.59 251.57 18.75 2.28 221.08 10.50 2.04 247.76 20.25 2.67 312.56 26.26 2.83 289.69 25.88 2.51 274.44 12.00 2.08 274.44 11.92 1.63 203.79 13.79 1.94 221.67 17.51 2.02 228.82 11. 92 1.67 207.37 13.41 1.94 228.82 19.75 2.06 232.40 12.30 1.94 264.58 15.65 1.86 221.67 19.38 2.06 228.82 19.75 2.25 239.55 26.83 2.53 261.00 24.22 2.45 257.43 20.87 2.18 225.25 22.36 2.10 225.25 24.97 2.02 214.52 27.95 2.33 264.58 14.91 1.86 225.25 16.02 1.86 221.67 36.52 2.72 314.63 30.56 2.45 275.30 26.09 2.29 261.00 24.22 2.07 241.77 30.56 2.47 270.22 30.56 2.63 295.11 23.32 2.39 266.66 29.07 2.39 277.33 30.56 2.55 291.55 27.95 2.31 277.33 38.39 2.87 334.22 25.34 2.23 291.55 28.32 2.47 291.55 27.95 2.35 280.88 29.07 2.47 284.44 25.34 1.99 248.88 26.83 1.95 227.55 26.09 2.23 270.22 27.95 2.19 277.33 20.50 1.83 248.88 13.79 1.75 266.65 28.70 2.27 291.55 30.56 2.39 291.55 30.56 2.31 234.44 25.32 2.09 245.87 30.09 2.29 274.80 29.35 2.21 274.80 30.09 2.25 274.80 29.35 2.21 278.41 26.42 2.17 274.80 19.08 1.70 242.26 34.12 2.57 318.19 24.58 2.05 249.49 55.56 0.0 75.19 44.95 4.67 68.51 37.82 0.0 55.14 45.42 0.0 39.26 52.34 0.0 60.15 48.76 0.0 62.66 47.67 0.0 60.99 40.71 0.0 43.44 36.23 0.0 40.44 40.96 0.0 48.02 38.70 0.0 53.08 37.93 0.0 37.91 46.10 0.0 45.49 41.95 0.0 48.02 49.46 0.0 42.12 41.35 0.0 42.12 41.52 0.0 48.02 43.59 0.0 52.23 43.07 4.61 65.71 38.91 4.73 64.87 37.12 8.48 63.19 44.80 6.43 58.13 45.10 4.63 52.23 47.45 7.60 62.34 43.46 5.06 45.49 44.45 4.11 43.81 51.83 6.49 71.61 50.07 5.81 62.34 49.46 4.73 60.66 43.87 6.35 55.83 44.26 8.88 66.66 40.54 10.66 73.33 43.08 12.42 62.50 52.26 7.45 62.50 48.20 9.53 65.83 49.89 3.20 58.33 55.10 12.77 72.50 49.62 4.71 54.16 47.44 0.0 61.66 42.38 0.0 56.66 42.11 7.80 62.50 41.59 0.0 60.00 41.68 0.0 56.66 44.75 0.0 68.33 43.60 0.0 61.66 42.11 0.0 51.66 43.82 0.0 40.83 44.04 4.47 66.66 46.69 0.0 66.66 43.34 0.0 66.66 45.40 7.59 60.65 46.09 8.87 67.21 46.00 5.49 62.29 47.77 6.93 65.57 47.08 6.83 62.29 49.07 6.31 59.83 40.78 0.0 39.34 51.16 6.68 68.85 48.81 8.68 59.01 TRACE METAL VALUES IN PPM; F E I N ? PB VALUES BELOW DETECTION LIMIT WHERE LISTED AS 0.0 125 APPENDIX B FIRST PARTIAL EXTRACTION EXPERIMENT RESULTS FIRST COLUMN LISTED UNDER EACH" ELF.ME NT REPRESENTS METAL EXTP.ACTEO IN 1.0 M HYOR OXYL AMINE HYDROCHLORIDE AN C 25? ACETIC ACID SECOND COLUMN REPRESENTS METAL EXTRACTED IN SUBSEQUENT 4:1 NITRIC:PERCHLORIC ACID 4TT4CK ALL SAMPLES PREVIOUSLY LEACHED WITH 1 M MAGNESIUM CHLORIDE ALL VALUES IN PPM EXCEPT FE IN % # ZN CU PB CO NI FE MN SERIES A INTERTIDAL SAMPLES (FEBRUARY 1974) 3 7.3 54.8 4. 6 22.8 3. 1 0.0 2.3 10. 3 4. 6 33. 3 .27 2.30 92.9 198.4 4 7.9 46.7 3. 6 18.0 2. 7 0.0 2.5 8.7 4. 4 32.1 .20 2.22 37.4 187. 5 12 8.3 40. 2 2. 6 10.0 3. 2 0. 0 2. 5 8. 0 3. 7 26.7 .23 1.74 111.8 158.9 13 10.0 44.0 2. 4 10.2 3. 0 0.0 2.3 11.8 3. 0 49.6 .24 2. 25 42.3 232. 6 18 5.9 40.0 0. 3 9.0 2. 1 0.0 1.7 11.3 3. 1 52.9 .12 2.10 9.8 239.4 20 9.6 37.8 2. 4 12.0 2. 4 0.0 2.2 9.2 3. 3 28.0 .23 1.85 34.9 169.9 21 3.9 40.2 1. 8 10.0 1. 8 0.0 2.7 8.5 3. 1 29.9 . 19 1.81 28.2 169.9 22 11.6 60.4 4. 4 23.6 4. 5 0.0 2.4 11. 0 4. 1 38.2 .26 2.44 36.1 209.4 23 11.9 68.6 5. 4 31.7 5. 4 0.0 3. 1 13.2 4. 7 39.2 .33 2.91 97.9 243.8 26 9.3 65.3 5. 4 26.3 5. 3 2.3 2.6 11.8 5. 5 41.3 .30 2.84 91.6 228.0 32 8.6 50.6 3. 6 20. 2 4. 6 1. 9 3.2 11.1 5. 1 40. 4 .24 2.28 65.4 193.9 34 6.8 39.1 2. 6 9.0 2. 2 0.0 3.7 11.9 4. 3 43.9 .14 1.95 75.3 209. 8 39 5.8 31.4 2. 6 7.6 1. 5 0.0 2.4 7.2 3. 2 31.1 .12 1.66 43.0 183.0 40 9.5 37.5 3.5 8.6 4. 5 0.0 5. 3 11.5 4. 3 41.1 .16 1.88 69.8 187.5 50 9. 2 47.5 3. 6 16.4 4. 5 0.0 2. 1 7.9 2. 6 30.7 .20 2.07 55.8 175. 8 51 10.2 48.1 3. 6 15.6 2. 5 0.0 2. 8 12. 1 3. 3 33. 9 .27 2.06 57.5 183.0 52 9.7 45.7 3. 4 14.0 5 . 6 0.0 2.2 11.0 2. 9 30.0 .22 2.03 57. 5 175. 8 53 11.0 48.1 3. 6 16.7 7. 3 0.7 3.1 11.6 3. 8 31.8 .23 1.92 75.3 164.4 54 22.0 41.6 15. .8 31.7 49.7 9.0 1.8 10.9 3. 0 28.2 .21 1.70 8.8 150. 8 55 26.1 62.8 11. ? 34.0 22. 3 3.0 3.5 12. 8 4. 2 37.8 .34 2.43 64.2 216.6 59 11.5 43.2 3. 0 12.9 5. 6 0.0 3.6 14. 1 4. 4 33.3 .24 1.81 134.3 157.6 SERIES B FORE-SLOFE SAMPLES (MARCH 1974) 19 22.0 67.7 3. 2 32. 1 13.7 10.1 3.1 13.0 4. 4 42. 7 .34 2.65 106. 7 221.2 25 4. 1 35.4 2. 6 95. 8 0.4 0. 0 2.3 9.7 3. 5 41.3 . 13 1.92 39.7 216.0 32 12.9 57.1 3. 8 22.9 7.1 0.0 3.1 11.5 4. 0 39. 2 .30 2.32 52.0 203.0 40 10.8 47. 5 3. 6 18.4 4.9 0.9 2.5 10.7 3. 6 30.7 .24 2.07 40.4 180.8 52 14.9 74.1 4. 4 38.1 8.8 5. 2 2.5 11.6 4. 2 41.2 .18 3 .00 53.6 251.2 66 14.7 68.5 4. 6 34.1 9.6 0.0 2.4 11.6 4. 0 37.0 .26 2.63 58. 2 238.6 72 18.4 78. 1 2. 8 41. 7 10. 1 5. 8 1.4 12.6 3. 3 40.0 .38 3.00 123.0 253.4 88 9.3 37.0 2. 8 12.4 3.4 0.0 2.1 10. 5 3. 1 28. 9 . 18 1.92 23.7 178.7 98 15.0 62.8 4. 4 31.7 7.6 2.6 2.3 10.7 3. 5 35.4 .24 2.50 48. 5 220.4 109 11.8 49.9 3. 2 17.6 5.0 0. 0 1.8 8. 2 3. 6 25.7 .11 1.70 44. 6 167.6 119 15.1 59.6 4. 6 25.9 9.4 3.5 2.9 14.0 3. 4 34.4 . 29 2.29 46. 7 198. 5 131 23. 6 84. 1 6. 4 51.7 16.6 6. 7 3.0 14.6 4. 1 42. 1 .41 3.13 69.0 268.8 132 24.7 86.5 6. 2 55. 2 19.7 11-2 2.4 14,4 4. 4 44. 7 .38 3.20 57. 5 275.6 144 6. 0 38.3 2. 4 11.3 2.4 0.0 2.5 11.4 3. 6 37.7 .20 1.81 34. 7 178.1 160 4. 5 35.4 1. 4 8.4 0.8 0. 0 1.8 9.6 2. 7 34.3 .12 1.70 21.1 205.0 186 9.3 46.5 4. 0 15.9 3.5 0.0 2.8 11.7 4. 9 39. 3 .28 2.29 57.9 203.0 214 13.5 58.8 2. 6 27. 9 7.3 0.0 2.7 12. 5 3. 7 37.8 .24 2.47 69.0 203.0 APPENDIX C CO, CU, FEm.MN, NI , P3 AND ZN CONTENT (PPM) OF SEDIMENT CORES FROM INTERTIDAL REGIONS OF THE FRASER DELTA-FRONT DEPTHS MEASURED IN CM NO DEPTH CO CU FE MN NI PB ZN 9 1. 6. 10.46 15. 66 1. 82 185.46 3 5.90 4.63 55.45 9 6. 11. 9. 54 16.56 1. 80 201.73 34. 51 5. 57 55. 45 9 11. 16. 12.15 18.30 1. 93 211.49 35.58 4.06 59.03 9 16. 21. 10.67 17. 90 1. 88 204.98 3 8. 3 8 4.22 56.34 9 21. 26. 12.31 17. 46 1. 90 204.98 37.54 4.10 56.34 9 26. 31. 1.1. 89 19.69 1. 93 211.49 40.35 6.28 58. 13 9 3 1 . 36. 14.60 25. 06 2. 27 240.77. 44. 12 7.27 65. 29 9 36. 41. 12.27 23.27 2. 11 224.50 42. 56 6.30 63. 50 9 41. 46. 12.70 22. 33 2. 11 234.27 40. 82 3. 73 57. 24 9 46. 5 1 . 13.75 27.75 2. 27 247.28 42.47 4.97 64. 39 9 51. 56. 17.80 31. 33 2. 42 299.34 45.07 4.65 66. 18 9 56. 61 . 14.98 27.75 2. 27 292.83 43. 65 3.30 62. 60 9 6 1 . 6 6. 11.77 25.51 2. 42 266.80 40.61 5. 29 64. 39 9 66. 71. 10. 84 19.24 2. 03 21 1.49 41.43 2.73 58.13 9 71. 76. 11.30 18.80 1. 9 5 195.22 41.62 2.82 57. 24 9 76. 80. 10.59 19.24 2. 03 195.22 43. 89 3.28 57.24 10 1. 6. 3.78 10 6. 11. 11.85 10 11. 16. 10.34 10 16. 21. 11.47 10 21. 26. 13.58 10 26. 3 1 . 12.22 10 31. 36. 14.12 10 36. 4 1 . 14. 29 10 41. 46. 13.40 10 46. 51. 13.57 10 51. 56. 10.02 10 56. 6 3 . 10.74 15.66 1.84 185.46 17.01 1.91 195.22 17.90 1.95 198.48 18.80 1.95 201.73 19.69 2.03 208.24 21.03 2.39 238.17 21.94 2.46 238.17 16.00 2.10 197.34 18.29 2. 21 207. 55 18.29 2.21 204.15 17.37 2.28 210.95 19.20 2.39 214.35 3 8. 00 0. 0 50.08 4 1 . 29 4. 56 55.45 42.70 5.02 57.24 42. 61 3. 96 55.45 44.36 2. 96 56. 34 40. 51 2. 96. 57. 93 44.05 3. 44 60. 69 38. 18 0. 0 57.01 41.91 3. 16 57. 93 40. 56 4. 12 57.01 38.72 2. 05 55.17 39. 84 2. 05 55. 17 0. 1. 12.26 1. 6. 10. 19 6. 1 1 . 10.31 11. 16. 11.71 16. 21. 9.31 2 1 . 26. 12.34 26. 31. 12. 09 31. 36. 9.77 36. 4 1 . 1 0.65 41. 46. 9.73 46. 51. 10.31 51. 56. 10. 19 56. 6 1 . 8.09 61. 66. 12.55 66. 71. 13.05 71. 76. 9.85 76. 82. 9.93 28.34 2.60 279.00 23.80 2.67 251.78 29.71 2.81 258.59 24.69 2.91 258.59 17.83 2.63 238.17 11.43 1.93 200.74 10. 97 1. 90 193.94 11.89 1.90 204.15 12.34 1.93 204.15 12.34 1.97 190.54 13.71 1.93 193.94 14.63 1.97 190.54 13.71 1.97 197.34 22.40 2.32 244.98 22.99 2.44 248.38 19.31 2.22 217.76 14.71 2.04 200.74 44.09 12.02 68.96 42.19 12.58 72.64 45.73 11.80 72.64 45.27 5.64 64.37 43.50 5.97 52.41 33.23 5.60 45.98 34.92 3.42 44. 14 33.15 3.14 44.14 34.34 1.51 44.14 32.30 2.90 45.C6 34.70 3.03 45.98 33.23 4.62 45.98 36. 12 3.94 47. 82 39.26 4.25 57.93 44. 68 5.44 55. 02 43.27 4.80 47.92 40.01 2.64 44.37 127 12 0. 1. 9.69 12 1. 6. 13.92 12 6. 1 1 . 9.97 12 11. 16. 8.79 12 16. 21. 11.41 12 21. 26. 11.49 12 26. 3 1 . 11.49 12 31. 36. 12.43 12 36. 41. 13. 38 12 41 . 46. 14.95 12 46. 51. 12.68 12 51. 56. 12.43 12 56. 6 1 . 13.59 12 61. 66. 14.04 12 66. 71 . 16.61 12 71. 76. 15.57 12 76. 81. 14.54 12 81. 86. 17.32 12 96. 9 1 . 12.52 12 9 1 . 96. 15.40 12 96.101. 14.66 12 101. 106. 14.57 12 106. 113. 12.31 14.71 1.86 272.20 38.16 3.01 381.07 23.91 2.22 285.80 17.01 1.97 244.98 22.99 2.29 289.21 18.39 2.22 253.59 16. 55 2. 58 272. 20 17.01 2.65 255.18 16. 55 2.40 238.17 28.51 2.69 302.82 17.47 2.22 248.38 17.01 2.15 244. 98 17.47 2.15 248.38 17.93 2.22 251.78 22.07 2.33 279.00 19.31 2.33 279.00 19.39 2.36 292.61 20.69 2.44 285.80 19.12 2.52 260.83 20.43 2.71 270.33 20.03 2.79 286.28 19.12 2.64 267.20 15.93 2.52 248.11 37.65 2. 34 46.15 52. 15 7. 08 74. 54 44.68 5. 21 56. 79 41.87 4. 52 46. 15 43. 13 5. 21 55. 02 43. 69 5. 08 49. 70 49.39 4. 16 55. 91 47. 97 3. 58 56. 79 48.21 6. 05 51.47 54. 88 7. 49 75. 43 46. 56 4. 13 56. 79 48. 21 5. 87 55.02 45.90 6. 07 53. 24 46.79 5. 12 65.67 42. 67 4. 91 60. 34 48. 45 3. 36 57. 68 47.74 5. 57 56. 79 46. 56 4. 97 58. 57 46. 03 4. 70 56.88 46. 31 5. 00 57. 79 47.78 3. 59 60. 50 47.74 2. 95 55. 98 47.60 3. 88 49.66 13 0. 1. 15.48 13 1. 6. 13.18 12 6. 1 1 . 12.52 13 11. 16. 12.44 13 16. 2 1 . 12.93 13 21. 26. 12.11 13 26. 31. 10.60 13 3 1 . 36. 8.88 13 36. 4 1 . 11.74 13 4 1 . 46. 12.44 13 46. 51. 11.49 13 51. 56. 11.33 13 56. 6 1 . 12.77 13 61. 66. 10.15 13 66. 7 1 . 11.33 13 71. 76. 10.72 13 76. 81. 10.04 13 81. 86. 10.29 14.57 2.41 324.45 13. 66 2.49 330. 81 13.20 2.34 299.01 12.29 2.41 313.09 12.74 2.26 292.64 12.29 2.34 324.45 12. 74 2.30 295. 82 12.29 1.70 241.75 11.84 1.81 311.73 13.66 2.00 321.27 12.29 2.07 302.19 13. 20 1.96 289.46 12.74 1.89 279.92 15.43 1.89 286.28 13. 66 2.00 292. 64 13.66 1.89 292.64 11.82 1. 79 314.60 25.46 2.17 336.84 64.69 0.0 46.95 59.58 0.0 49.66 54.90 0.0 46.95 59.53 0.0 46.95 51.44 0.0 43.34 49.91 0.0 46.95 48.66 0.0 43.34 39. 78 0.0 40. 63 48.24 0.0 42.44 56. 03 0.0 46. 95 54.57 0.0 46.95 48.20 0.0 46.05 48.47 0.0 46. 95 46.35 0.0 46.95 45. 11 0.0 46.95 47.92 0.0 46.95 44.37 3.20 42.76 47.42 4.50 55.23 15 0. 1. 7.98 15 1. 6. 7.45 15 6. 1 1 . 10.00 15 11. 16. 8.89 15 16. 2 1 . 10.54 15 21. 26. 9.79 15 26. 31. 8.64 15 31. 36. 9.96 15 36. 4 1 . 12.07 15 4 1 . 4 6 . 10.62 15 46. 5 1 . 10.66 15 51. 56. 9.22 15 56. 64. 8.35 12.27 1.71 241.51 12. 73 2.09 279.64 13.64 2.28 327.31 12.73 1.90 273.29 12.73 2.21 298.71 13.64 1.90 238.33 15. 45 1.98 260. 58 15.00 2.06 301.99 15.00 1.98 238.33 15.00 2.06 241.51 13.64 1.90 228.80 14.55 1.98 238.33 14.55 2.02 222.44 36.23 3.24 40.98 49.71 2.68 43.65 53.34 2.89 47.22 46.20 4.41 40.09 50.46 0.0 44.54 40.86 0.0 40.98 41.33 0.0 41.87 41.90 0.0 44. 54 37.21 0.0 43.65 42.15 2.22 43.65 37.43 0.0 42.76 37.85 0.0 42.76 3 7.64 0.0 44.54 128 NO DEPTH CO 16 0. 1. 8.89 16 1. 6. 12.28 16 6. 11. 12.40 16 11. 16. 11.62 16 16. 21. 13.32 16 21. 26. 11.86 16 26. 31. 9.87 16 31. 36. 11.97 16 36. 4 1 . 3.30 16 41. 46. 10.19 16 46. 51. 11.15 16 51. 56. 8.69 16 56. 61 . 9.71 16 61. 66. 9. 14 16 66. 70. 11.64 CU FE MN NI . 14.55 1.98 263.75 44.98 13.64 2.44 31 7. 78 6 1 . 66 12.27 2.28 298.71 56.69 13. 64 2.28 305.06 59. 08 12. 27 2.02 260. 58 42. 80 13.64 2.09 241.51 43.45 12. 24 1.68 196. 49 38. 00 16.83 2.23 242.10 50.05 12.24 1.68 175.44 35.98 13. 77 1.88 217. 54 37. 05 13.77 1.88 207.02 37.27 13.39 1.74 182.46 36.71 12.62 1.92 189.47 38. 26 13. 39 1.81 171. 93 39. 51 25.25 2.44 221.05 44.44 PB ZN ?SAND 0.0 41.87 93 . 0.5 0.0 48. 11 96. 1-2 0.0 44. 54 98. 1.6 0.0 48.11 99. 0.6 0.0 44. 54 93. 1.0 0.0 42.76 99. 1.4 4. 78 38.78 100. 1.4 0.0 47.21 79. 4.1 1.27 36.25 98. 1.3 0. 0 37. 93 97. 1.5 0.0 36. 25 98. 1.1 0. 0 35.41 97- 2.3 0.0 35.41 88. 1.9 0.0 34.56 97. 1.7 0. 0 52.27 66. 2.6 8 0. 1. 7.83 8 3. 8. 9.44 8 8. 13 . 11.24 8 13. 18. 8.78 8 18. 23. 8. 96 8 23. 28. 9.74 8 28. 33. 8.63 8 33. 3 8. 9.74 8 38. 4 3 . 8.99 L8 43. 48. 11.19 8 48. 53. 9.14 8 53. 58. 7.94 18 58. 6 3 . 8.00 8 63. 6 7 . 10.98 14.15 1.92 224.56 16.45 2.16 238.60 15.30 2.16 252.63 13.39 1.81 266.67 14.54 1.68 256.14 14.15 1.74 266.67 16.07 1.71 259.65 14.54 1.81 256.14 16.07 1.74 221.05 15.30 1.99 242.10 18.74 1.68 217.54 17.21 1.64 200.00 15.42 1.71 212.53 17.74 2.05 246.81 36. 54 0.0 33. 72 42.08 0.0 36.25 45.62 0.0 37.09 41.25 0.0 38. 78 35.55 0.0 37.93 3 7. 87 0. 0 37.93 39.56 0.0 38.78 38.43 0.0 39.62 37.83 0.0 37.09 41.42 0.0 37.93 33. 20 0. 0 38. 78 32.47 0.0 38.73 32.36 0.0 37.80 41.94 0.0 41.09 19 0. 1. 9.31 19 1. 6. 9.44 19 6. 1 1 . 9.18 19 11. 16. 10. 85 19 16. 2 1 . 8.64 19 21. 26. 9.92 19 26. 3 1 . 8.42 19 31. 36. 9.92 19 36. 41. 11.76 19 4 1 . 46. 9.12 19 46. 51. 9.53 19 51. 56. 12.75 19 56. 6 1 . 9.12 19 61. 66. 9. 95 19 66. 7 1 . 10.17 19 71. 76. 11.84 19 76. 82. 7.08 17.74 1.91 263.95 39.17 14.27 1.98 281.09 39.86 15.04 2.05 284.52 38.90 24.29 2.26 263.95 38.86 23.90 2.19 253.67 38.78 18.12 1.95 222.82 34.81 21. 59 2.12 239. 96 35. 92 22.36 2.15 239.96 38.21 25.45 2.46 260.52 42.29 23.90 2.22 250.24 40.86 21.59 1.85 277.67 38.78 29.30 2.29 294. 80 44. 43 20.82 1.91 267.38 38.05 21.98 1.98 274.24 41.05 23.90 2.19 294.80 39.63 25.83 2.29 308.52 42.56 14.65 1.61 229.67 31.94 0.0 39.45 9 9 . 2.1 0.0 40.27 97. 2.0 0.0 38.62 89. 0.9 0.0 46. 84 68. 1.0 0.0 47. 66 82. 1.4 0.0 42.73 84. 2.0 0.0 45.20 81. 2.2 0.0 49.31 81. 1.5 0.0 51.77 69. 2.5 0. 0 46. 02 75. 1.9 0.0 43.55 80. 0.9 0.0 58.35 52. 1.2 0.0 46. 84 85. 0.9 0.0 46. 02 82. 1.8 0. 0 52. 59 70. 2.6 0.0 53. 42 71. 2.8 0.0 34. 51 99. 1.3 129 NO DEPTH CO CU FE 21 0. 1. 8.96 20. 05 2.05 21 1. 6. 11.46 25.06 2.15 21 6. 11. 11.29 25.63 2.33 21 11. 16. 11.02 21.40 1.99 21 16. 2 1 . 11.08 22.95 2.06 21 21. 26. 9. 74 22. 18 2.06 21 26. 3 1 . 10.85 28.01 2.30 21 31. 36. 10.90 26.07 2.37 21 36. 41 . 11.02 25. 29 2.37 21 4 1 . 46. 11.93 25.68 2.40 21 46. 51. 10. 76 25. 68 2.33 21 51. 56. 11.52 28. 40 2.57 21 56. 61. 11.61 29.13 2.57 21 61. 66. 13. 17 27.23 2.54 21 66. 7 1 . 11.40 23.34 2.40 21 71. 76. 12.78 24. 51 2.40 MN NI PB ZN 2SAN0 % L I 195.39 31.87 7.98 56.70 205.68 35.27 9.79 61.63 214.45 43.35 6.01 61.79 201.05 38.36 3.96 54.33 207.75 39.90 8.19 57.67 207.75 39.17 6.68 57.67 251.31 44.82 2.61 59.32 227.85 42.52 0.0 59.32 221.20 42.14 4.32 60.97 227.85 42.14 4.26 57.67 224.50 41.96 0.0 59.32 241.26 43.35 0.0 62.62 241.26 45.08 3.19 62.62 221.20 43.48 4.92 60.14 234.55 42.27 0.0 59.32 234.55 41.10 0.0 56.85 22 0. 1. 8.81 22 1. 6. 9.10 22 6. 11. 9. 01 22 11. 16. 10.96 22 16. 2 1 . 13.67 22 21. 26. 11.05 22 26. 3 1 . 12.31 22 31. 36. 12.69 22 36. 4 1 . 11.69 22 4 1 . 46. 11.93 22 46. 51. 10. 72 22 51. 56. 11.63 22 56. 61. 1 0. 50 22 61. 66. 9.90 22 66. 7 3 . 11.35 14.01 1.58 167. 54 17.51 1.65 160.84 21.40 1.89 167.54 28.01 2.13 187.64 22.57 2.40 211.10 18. 68 2.13 201.05 19.45 2.19 '207. 75 19.74 2.30 216.17 19.74 2.23 219.45 17.37 2.16 209.62 16.98 1.99 203.07 15.79 1.95 186.69 15.79 1.92 186.69 15.00 1.99 203.07 16.58 1.92 206.35 28.62 0.0 45.31 33.73 0.0 51.08 33.14 0.0 60.14 37. 42 0.0 69. 21 40.07 0.0 56.02 38.36 0.0 34.60 39. 04 0.0 35. 43 39.89 7.05 50.87 41.54 7.07 51.69 38.92 5.68 49.23 38.08 4.97 44.31 39. 13 4.92 42. 67 37.16 0.0 42.67 39.30 2.54 44.31 38.71 5.66 42.67 23 1. 6. 8.42 23 6. 11 . 8.75 23 11. 16. 6.80 23 16. 21. 11.48 23 2 1 . 26. 11.14 23 26. 31. 11.41 23 31. 36. 11.44 23 36. 4 1 . 11.69 23 41. 46. 11.02 23 46. 5 1 . 10.78 23 51. 56. 10.47 23 56. 61 . 11.20 23 61. 66. 10.93 23 66. 71. 11.75 23 71. 76. 9.50 23 76. 83. 9.23 17.37 1.92 180.14 15.00 1.81 170.32 15.79 1.85 163.77 22. 51 2. 61 229.27 18.56 2.09 212.90 20.53 2.19 222.72 15.79 2.02 209.62 16.58 1.92 203.07 14.61 1.85 203.07 13.82 1.81 203.07 14.21 1.85 193.24 14.61 1.88 203.07 15.00 1.92 206.35 19.74 2.27 216.17 15.96 1.79 202.76 15.16 1.83 189.68 33.99 3.88 49.23 29.33 0.0 43.49 29.90 0.0 44. 31 40.82 0.0 54.97 39. "57 0.0 54. 97 42.59 0.0 59.08 28. 08 0.0 51.69 39.55 0.0 51.69 37.99 0.0 50.87 36. 82 0.0 46. 77 35.90 0.0 45.95 36. 82 0.0 46. 77 36.32 0.0 46.77 38.12 6.71,50.87 36. 86 0.0 46. 92 38.56 0.0 46.11 130 NO DEPTH CO CU FE MN NI PB ZN 25 1. 6. 7.35 11.57 1.52 209.30 33.15 o.o- 40.45 25 6. 11 . 7.17 11.57 1.45 202.76 33. 11 8.32 40.45 25 11. 16. 7.32 11.57 1.56 196.22 34.55 6.02 40. 45 25 16. 2 1 . 8.69 11. 17 1. 66 212.57 37. 56 5.39 43.68 25 21. 26. 10.36 17.16 1.96 274.71 42. 96 0.0 50. 15 25 26. 3 1 . 13.32 30.72 2.64 372. 82 50. 14 7.59 66.33 25 31. 36. 17.34 43.09 3. 25 480. 74 61. 20 8. 83 79. 27 25 36. 4 1 . 18.02 48 .63 3.42 510.17 64. 13 10.33 88. 98 25 41. 46. 15.08 31. 92 2.77 408.79 52.38 5.27 74.42 25 46. 5 1 . 13.98 30.32 2.64 418.60 49. 20 5. 20 67. 95 25 51. 56. 14.17 23.94 2.37 327.03 47. 32 0.0 59.86 25 56. 6 1 . 12. 39 14. 76 1.86 255.08 42. 16 0. 0 46. 92 25 61 . 66. 11.15 13.57 1 .69 251.81 36. 15 0.0 42. 06 25 66. 71. 14.93 19. 15 1. 83 402.25 46.72 0.0 51.77 SSAND % L I 29 1. 6. 9.82 29 6. 11. 10.06 29 11. 16. 11.09 29 16. 2 1 . 9.85 29 21. 26. 10.54 29 26. 31. 15.73 29 31. 36. 12.48 29 36. 41. 10.37 29 4 1 . 4 6. 10.15 29 46. 51. 11.01 29 51. 56. 11.21 29 56. 6 1 . 10.30 29 61. 66. 11.26 29 66. 7 1 . 10.65 29 71. 76. 9.49 16.76 1.76 196.22 36.31 16.76 1.76 202.76 36.98 13.97 1.69 192.95 38.10 14.76 1.69 186.41 37.07 19.95 1.89 215.84 42.87 26.43 2.85 292.04 52.32 18.82 2.06 220.81 43.43 15.93 1.80 174.51 39.68 13.39 1.66 170.95 36.41 14.12 1.73 170.95 38.65 13.03 1.73 167.39 39. 08 13.76 1.77 170.95 37.53 13.03 1.59 142.46 35.00 14.12 1.73 167.39 39.78 14.12 1.70 163.83 36.05 0.0 46.11 95. 1.8 0.0 48. 53 95. 1.2 0.0 46. 11 95. 0.4 0.0 45. 30 93. 0.7 0.0 51.77 66. 1.9 7.46 67.16 63. 1.8 4.36 50. 16 80. 1.6 3.63 44.21 84. 1.2 0.0 42. 51 95. 0.7 0.0 41. 66 96. 1.2 0.0 3 9. 96 93. 0.9 0.0 42. 51 88. 0.8 0.0 36.56 9 3 . 0.9 0.0 38. 26 100. 1.1 0.0 36. 56 95. 0.9 30 1. 6. 11.97 30 6. 11 . 12.27 30 11. 16. 10.40 30 16. 21. 9.47 30 21. 26. 9.47 30 26. 31. 8.61 30 31. 36. 8.69 30 36. 4 1 . 6.82 30 41. 4 6. 9.57 30 46. 5 1 . 13.04 30 51. 56. 12.65 30 56. 6 1 . 11.95 30 61. 67. 13.06 43.44 2.13 188.76 33.30 2.16 185.20 18.82 2.02 224.37 18. 10 2.16 231. 50 13.03 1.88 206.57 12.31 1.80 195.83 11.58 1. 70 185. 20 10.86 1.66 185.20 19.91 2.24 249.30 14.12 2.16 284.92 13.76 1.91 345.47 12.42 1.81 279.82 13.15 2.02 215.25 46.38 28.79 88.42 44.27 18.46 71.41 37.99 10.63 53.56 40. 55 4.59 52. 71 39.22 0.0 41.66 39.38 0.0 39.96 33. 50 0.0 38. 26 33.63 0.0 35.71 42.09 0.0 51.01 41.32 0.0 48.46 38.85 4.38 45.91 36. 84 6.58 48.03 40. 72 6.92 46. 38 131 NO DEPTH CO CU FE MN NI PB ZN %SAND %Ll 31 0. 1. 12. 09 34. 70 2.64 430.49 50.94 8.12 67.91 4 1 . 2 .3 31 1. 6. 11.84 33.61 2.53 322.87 49. 07 4. 72 67. 91 40. 3 .1 31 6. 11. 12.07 33.61 2.31 283.41 50.23 0.0 61.28 6 5 . 2 .0 31 1 1 . 16. 11.35 33.61 2.53 315.70 48. 64 4.47 66. 25 46. 2 .5 31 16. 2 1 . 12.11 31.42 2.53 312.11 51.90 7.03 63. 77 43. 1 .1 31 21. 26. 11. 57 30. 68 2.60 287.00 50. 02 0.0 62. 11 50. 1 .8 31 26. 3 1 . 11.77 31.42 2.60 261.88 4 8. 64 0.0 61. 28 54. 1 .5 31 31. 3 6. 12.36 33.97 2.64 269.06 52. 18 7.14 66. 25 39. 2.9 31 36. 4 1 . 11.34 33.61 2.35 258.30 54. 15 7.01 63. 77 40. 2 .4 31 4 1 . 46. 13.20 32.88 2.49 265.47 54. 51 5.19 64. 60 44. 1 .9 31 46. 51. 11.91 34. 34 2. 53 3 04.93 55.88 0.0 64.60 36. 2 .7 31 51. 56. 13.22 35.07 2.53 315.70 52. 18 6. 20 65. 42 44. 2 .2 31 56. 6 1 . 12.07 35.80 2.71 319.28 53.68 6.18 67.91 33. 1 .6 31 61. 66. 13. 79 37. 26 2.75 337. 22 53. 83 3.98 69. 57 24. 1 .2 31 66. 72. 10.94 31.05 2.53 301.34 50.62 5. 53 62. 11 44. 1 .8 33 0. 1. 11 .66 34.70 2. 89 287.00 46.54 11.27 74. 53 27. 4.7 33 1. 6. 11.66 29.22 2. 71 27 6.23 43. 23 7.72 71. 22 40. 2.4 33 6. 1 1 . 12.11 32.15 2. 60 261. 83 46.05 9.24 7C. 39 35. 2.5 33 11. 16. 12.07 33. 61 2. 64 251.12 47.62 8.51 72.88 38. 2.0 33 16. 21. 13.32 30.14 2. 44 228.05 46. 26 8. 00 65. 74 48. 2.2 33 21. 26. 12.80 27.94 1. 94 231.67 48. 37 5.22 59. 17 59. 1.3 33 26. 31. 11.28 26.47 2. 23 224.43 46. 12 7.82 59. 99 63. 0.2 33 31. 36. 11.18 25.73 2. 34 224.43 43. 29 4.32 59. 99 63. 0.8 33 36. 4 1 . 11.38 22.79 2. 05 202.71 39.25 5. 24 53.42 74. 0.6 33 41. 46. 9.57 22.06 2. 05 206. 34 37. 17 4.14 54. 24 71. 1.1 33 46. 51. 11.87 24.63 2. 23 202.71 39. 12 4.14 59. 17 59. 1.4 33 51. 56. 10.69 23. 53 2. 09 206.34 37.47 6.49 55.06 65. 1.6 33 56. 6 1 . 12.14 27.57 2.44 238.91 41. 68 6.19 64. 92 54. 2.0 34 0. 1. 14.95 36.02 2 .98 343.89 45.68 6. 55 70.67 18. 2. 5 34 1. 6. 13.61 36.39 2. 66 224.43 44. 57 8. 10 71.49 17. 1 . 9 34 ' 6. 1 1 . 15.30 36.02 2. 59 217.20 48.37 7. 27 70.67 24. 1. 5 34 11. 16. 13.94 32.35 2. 48 224.43 45.24 7. 13 65. 74 25. 1. 2 34 16. 2 1 . 14.98 35. 66 2. 63 246.15 48. 44 7. 88 72.32 19. 2. 8 34 21. 26. 14.31 30.88 2. 59 231.67 44.67 7. 50 65.74 27. 2. 3 34 26. 3 1 . 14.38 34. 19 2. 80 275. 11 49.23 5. 24 68. 21 32. 3. 0 34 31. 36. 15.88 36. 76 2. 73 296.83 52. 57 6. 69 69. 85 20. 3. 2 34 36. 4 1 . 15.18 36.76 2. 66 307.69 49. 43 6. 91 69.85 24. 3. 4 34 4 1 . 46. 14.06 30.88 2. 59 282.35 40. 68 5. 93 63. 28 33. 4. 5 34 46. 5 1 . 14.53 34.19 2. 66 289.59 40.78 4. 38 69.03 24. 0. 7 34 51. 56. 14.43 35. 29 2. 70 271.49 40. 45 6. 29 69.85 23. 1. 9 34 56. 6 1 . 12.77 30.74 2. 91 260.47 41. 37 4. 66 61. 63 32. 2. 1 34 61. 66. 12.10 30.37 2. 49 271.63 44. 97 5. 76 64.92 39. 2. 1 34 66. 70. 13.02 32.22 2. 56 286.51 43. 76 8.03 69. 03 34. 2.6 132 NG DEPTH CO CU FE MN NI PB ZN 35 0. 1. 11.65 30.37 2.56 346.05 40.38 17.24 75.60 35 1. 6. 10.76 22.96 2.27 26 7.91 37.46 10.82 59. 99 35 6. 11. 12.60 31.85 2.59 275.35 45.47 11.29 62.46 35 11. 16. 11.75 29.63 2.49 271.63 44. 54 10.55 67.39 35 16. 21 . 11.93 25.56 2. 31 267.91 45.91 10.72 61.63 35 21. 26. 13. 09 23. 70 2.31 241.86 41.13 5.27 59.99 35 26. 3 1 . 12.15 15.93 1.99 212.09 40. 52 4.31 46. 02 35 31. 36. 10.71 17.78 1.95 215.81 35. 37 2.20 41.09 35 36. 4 1 . 10.93 17.04 1. 95 193.49 36. 21 0.0 45.20 35 4 1 . 46. 11.23 19.26 2.13 230.70 3 9.04 0.0 49. 31 35 46. 51. 11. 80 25. 93 2.49 271.63 44.40 0.0 56.70 35 51. 56. 9.56 19. 26 2.24 241.86 37. 57 0.0 49. 31 3 5 56. 61. 8.40 17.04 1.95 223.26 36. 14 0.0 42. 73 35 61. 66. 9.14 18. 52 2.13 238.14 41. 55 0. 0 46. 02 35 66, 71. 9.58 16.67 1.99 253.02 37. 18 0.0 46.02 35 71. 76. 9. 92 17. 04 2.02 230.70 36.59 0.0 42.73 35 76. 83. 9.68 17.78 1.99 223.26 34. 75 0.0 42. 73 SSAND %Ll 36 0. 1. 9.14 36 1. 6. 13.81 36 6. 1 1 . 16.30 36 11. 16. 17.90 36 16. 21. 13.93 36 21. 26. 13.20 36 26. 31. 12.56 36 3 1 . 36. 11.73 36 36. 4 1 . 13.35 36 41. 46. 10.90 36 46. 51. 12.54 36 51. 56- 8.56 36 56. 6 1 . 7.89 36 61. 66. 10.13 36 66. 71. 8.16 27.04 2.56 334.88 28.76 2.65 253.61 29.12 2.86 272.26 29.49 2.75 268.53 27. 28 2. 50 257.34 20.65 2.29 234.96 18.43 2.22 223.73 20.28 2.36 234.96 19.54 2.11 212.59 18.43 1.90 193.94 22.86 2.47 249.88 19.54 2.22 231.24 16.96 1.86 201.40 15.48 1-90 212.59 17.33 1.79 208.86 40.21 13.46 69.03 45-78 7.27 68.95 51.30 6.49 76.43 53.26 6.12 70.61 46.59 2.13 55.66 42. 84 0.0 51. 51 42.94 0.0 49-01 44. 71 0-0 49. 84 42.35 0-0 49.01 41.19 0.0 43.20 42. 44 0. 0 54. 00 41.91 0.0 48.18 36.21 0.0 39. 88 36.70 0.0 41. 54 35.76 0.0 41.54 3 7 0. 1. 14.24 37 1. 6. 12.03 37 6. 11. 13.43 37 11. 16. 13.38 37 16. 21. 12. 72 37 21. 2 6. 12.89 37 26. 3 1 . 15.33 37 31. 36. 14.19 37 36. 4 1 . 14.62 37 41. 46. 14.02 37 46. 51. 9.78 37 51. 56. 11.25 37 56. 61. 11.20 37 61 . 66. 10.40 37 66. 7 3 . 11.55 36.50 2.86 440.09 33.92 2.65 328.21 36.13 2.61 35C.58 32.44 2.61 324.48 30.60 2.57 309.56 23.96 2.29 279.72 31.71 2.61 331.94 32.33 2.78 322.66 24.53 3.14 345.95 24.53 2.54 309.35 22.30 2.11 272.76 27.50 2.64 312.68 25.27 2.26 306.03 20.44 2.04 296.05 27.50 2.57 345-95 47. 16 8.74 70. 61 46.28 4.55 65.63 45.71 0-0 66.46 44. 17 2. 81 64. 80 44.51 4.93 63.14 39.80 0.0 54.00 47.60 0.0 64.80 51.06 6.39 65.51 58. 21 3. 31 63. 05 48.35 4.09 55.68 41.48 2.27 46.67 42.66 3.31 59.77 45.59 3.57 51.59 40. 75 2.13 42. 58 45.79 3.55 58.96 NO DEPTH CO CU FE MN NI PB ZN 38 0. 1. 14.43 39.40 3. 17 409.15 51.17 6.75 72.06 38 1. 6. 12.54 26.02 2. 54 306.03 43. 22 6.33 60.59 38 6. 1 1 . 12.92 26. 76 2. 61 332.64 44.40 3.87 55. 68 38 11. 16. 12.38 28. 25 2. 61 345.95 45. 17 3.60 57.32 38 16. 21. 8.17 17.84 2. 11 279.42 43. 86 0. 0 45. 85 38 21. 26. 7.48 17.10 -> 33 259.46 41.48 0.0 45. 04 38 26. 31. 9.55 16. 35 2. 40 272.76 44. 98 0. 0 45. 04 38 31. 36. 10.08 16.35 2 . 78 28 2.74 46. 72 0.0 47. 49 38 36. 41. 9.41 15. 98 2. 01 246. 15 39.42 0.0 39.30 38 41 . 46. 7.61 16. 73 1.97 252.81 ?6. 77 0. 0 40. 12 38 46. 51. 7.98 17. 34 2. 08 252.81 39.61 0.0 40.94 38 51. 56. 8.46 17. 84 1. 90 239. 50 36. 05 0. 0 38. 49 38 56. 6 1 . 8.80 18.58 2. 1 1 252.81 37.49 0.0 44. 22 38 61. 66. 11.24 19. 83 1. 77 230.41 40. 80 0.0 41.97 ?SAND % L I 60 0. 1. 14.61 32.04 2. 44 60 1. 6. 12.39 16.40 1. 73 60 6. 11. 12.97 18. 69 1. 94 60 11. 16. 12.97 20.21 2. 12 60 16. 21. 13.14 14.49 1. 84 60 21. 26. 12.33 13.35 1. 77 60 26. 3 1 . 13.89 13.73 1. 84 60 31. 36. 13.08 13.73 1. 87 60 36. 4 1 . 12.99 12. 73 1. 84 60 4 1 . 46. 11.67 13.73 1 .77 60 46. 51. 12.39 13. 35 1. 77 60 51. 56. 12.47 12.20 1. 84 60 56. 61. 13.40 12.20 1. 91 60 61. 66. 12.47 12. 59 1. 84 60 66. 7 1 . 11.55 12.20 1. 91 60 71. 78. 11.24 12. 20 1. 91 385.17 42. 72 15.62 77. 23 5 1 . 2.5 216.66 36. 59 12.05 52. 89 95. 1.6 22 3.54 37. 50 9.22 54.57 88. 1.5 237. 29 38. 45 5. 49 54. 57 80. 0.7 213.22 36.23 5.63 50.37 93. 0.9 196.02 3 4. 63 5.34 47. 01 95. 1.7 202.90 34. 81 6.42 45. 33 95. 1.6 202.90 36. 59 5.06 43.65 94. 2.0 192.59 3 5.32 4.39 41. 97 95. 1.8 189.15 34.38 5.74 41.97 93. 1.8 192.59 35. 87 3.03 41 . 97 94. 1.6 199.46 35. 87 6.39 41. 97 94. 1.2 192.59 34. 31 6.07 41 . 13 96. 1.0 199.46 31. 90 7. 81 41. 97 92. 1.1 192.59 33. 73 6.13 41.13 95. 0.9 192.59 33.73 3.02 41 . 13 94. 1.1 TRACE METAL VALUES IN PPM, FE IN % PB VALUES BELOW DETECTION LIMITS WHERE LISTED AS 0.0

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