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Apatite in a glacial lake Reid, Ruth Pamela 1979

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APATITE IN A GLACIAL LAKE by RUTH PAMELA RE ID B.Sc.  Queen's University, 1972  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE  in THE FACULTY OF GRADUATE STUDIES Department of Geological Science  We accept this thesis as conforming to the required standard  THE UNIVERSITY OF BRITISH COLUMBIA April, ©  1979  Ruth Pamela Reid, 1979  In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives.  It is understood that copying or publication  of this thesis for financial gain shall not be allowed without my written permission.  Department of  Geological Sciences  The University of British Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5  Date  April 12, 1979  ii  ABSTRACT  Apatite  is  a common accessory  mineral  in the  source  rocks for  glacial debris supplying recent sediments to many Canadian lakes.  Chemical  analyses of sediments in Kamloops Lake, British Columbia suggest that apatite may comprise a significant  portion of the total  the  this  phosphorus load to  the lake, thereby overestimating the trophic state that would be predicted by the relationship between total phosphorus load and the ratio of mean depth to flushing time.  A method has been developed which uses scanning electron  microscopy and energy dispersive X-ray spectrometry for direct identification of apatite.  This method has been used to examine the apatite content of  various size fractions in Kamloops Lake sediments. obtained  by  this  concentrations  of  direct the  examination  indirect  correlate  chemical  Apatite well  analyses  with  concentrations the  and indicate  apatite that,  in  addition to comprising as much as 70% of the total phosphorus load, apatite may comprise phosphorus  as  load.  much as  20% of  Therefore,  the  estimates  "dissolved" of  lake  (<0.45  urn)  productivity  inorganic could  be  erroneous even i f dissolved rather than total phosphorus values are used for the estimation.  CONTENTS PAGE Abstract  ii  Contents  iii  List of Figures  iv  List of Tables  v  Acknowledgements  vi  Introduction  1  Methods Physical Separation, Identification  and Quantification  of Apatite Selective Chemical Extraction of Apatite  8 12  Analytical Results Physical Separation  13  Chemical Extraction  18  Conclusions  25  References  27  Appendix 1.  Size Separation of Silt Particles  30  Appendix 2.  Procedure for Heavy Liquid Separation of Apatite . . .  31  Appendix 3.  The Apatite Fraction: S.E.M. Sample Preparation and Examination  35  Appendix 4.  Data from Heavy Liquid Separation  36  Appendix 5.  Data from S.E.M. Examination  38  Appendix 6.  Observed Apatite Concentrations  40  Appendix 7.  Contribution of Apatite to the "Dissolved" Phosphorus  iv LIST OF FIGURES PAGE  Figure 1.  The Vollenweider Relationship  2  Figure 2.  Location Map; Kamloops Lake, B.C  4  Figure 3.  The Selective Chemical Extraction of Inorganic Phosphorus  4  Figure 4.  Heavy Liquid Separation of Apatite  9  Figure 5.  S.E.M. X-ray Identification  Figure 6.  Particle Size Distribution, Total Sample  14  Figure 7.  Particle Size Distribution, Individual Size Fractions . .  14  Figure 8.  Typical Kamloops Lake Apatites  15  Figure 9.  X-ray Emission Spectrum of Apatite  15  Figure 10.  0.45 ym Apatite and Monazite  19  Figure 11.  X-ray Emission Spectrum of Monazite  19  Figure 12.  Correlation between Apatite Concentrations from  Figure 13.  of Phosphate  Grains  9  Chemical Extraction and Physical Separation  23  Apatite Concentration vs. Grain Size  24  LIST OF TABLES PAGE Table 1.  Apatite Concentrations from Physical Separation  17  Table 2a.  Extraction of Apatite Standards  20  Table 2b.  Extraction of Apatite from Spiked Sediment Samples  20  Table 3.  Extraction of Apatite from Kamloops Lake Sediments  22  Table 2-1. Centrifligation Times  34  Table 4-1. Data from Heavy Liquid Separation  37  Table 5-1. Data from S.E.M. Examination  39  Table 6-1. Observed Apatite Concentrations  41  vi  ACKNOWLEDGEMENTS  The  author gratefully  acknowledges both the technical  assistance and  personal support given throughout this project by thesis supervisor Dr. W.C. Barnes.  Discussions  of  techniques  Lavkulich were very useful.  with  Dr. M.A. Barnes  and Dr. L.M.  The author would like to thank Dr. C.H. Pharo  for the suggestion of the research topic and Dr. C.H. Pharo, C.B.J. Gray, R. Kirkland and V. Chamberlain at the National Water Research Institute, West Vancouver for  stimulating  Chemical extractions were  performed  assistance  in  Chamberlain. Science Barnes.  discussion  of apatite  by R. sample  Kirkland  of  phosphorus  techniques.  and particle size analyses for this study and V.  collection  was  Chamberlain at  N.W.R.I.  Field  provided by Dr. C.H. Pharo and V.  Laboratory expenses for  the  and Engineering Research Council The author was  extraction  project  were met  Grant A-7027  supported throughout  the  held  project  by National by Dr. W.C.  by a National  Research Council Postgraduate Scholarship (1976-1978) and a Gulf Oil Graduate Fellowship (1978-1979).  The manuscript was improved by the suggestions of  Dr. C.H. Pharo and Dr. W.C. Barnes.  1 INTRODUCTION  Phosphorus is often the limiting nutrient controlling organic growth in aquatic systems in temperate zones (Gakstatter et al_., 1975).  Vollenweider  (1968) and Vollenweider and Dillon (1974) have developed an empirical relationship for lakes which relates annual total phosphorus load, mean depth and flushing time to the trophic state, or productivity of the lake.  This rela-  tionship, seen in Figure 1, has been used in North America and in Europe as a guide to the degree of eutrophication of lakes and to permissible loading levels (Dillon and Kirchner, 1975; Yeasted and Morel, 1978). Recent investigations  of forms of  phosphorus  in lake sediments have  shown that a Targe portion of the total phosphorus in some lakes is present as apatite (Williams and Mayer, 1972; St. John et aj_., 1976).  The most abun-  dant form of primary apatite in nature is fluorapatite [CastPO^F] (Williams et aj_.,1976, Deer et aj_., 1966) and since the solubility of fluorapatite in lake water is extremely low, it is unlikely to be more than a minor source of phosphorus for biological growth.  This conclusion is supported by Sagher and  Harris (1972), Sagher et al_. (1975), Syers et a l . (1973), and Wil 1 iams et a]_. (1976).  Sagher and Harris (1972) and Sagher et al_. (1975) investigated  the  availability of sediment phosphorus and concluded that the non-occluded Febound phosphorus was the most available form of sediment phosphorus, whereas the apatite phosphorus was of limited availability.  Syers et al_. (1973, p.8)  conclude  "essentially  that  Ca-P  (apatite)  in  lake  water  is  immobile".  Williams et a l . (1976) comment that a high input of apatite-P to Lake Erie prior to 1850 did not render the (1978) have shown that  lake eutrophic.  However, Smith et aj_.  naturally occurring apatites may provide a source  of orthophosphate for growth of bacteria and algae.  At present, the question  2  10.  -i  1 — i — i i i 111  1  1—i—i—i i i i i  1  i i i i i i 11  "1  1—l I I I I I  1  1967/70  EUTROPHIC  5^ KOOTENAY  1960/64 0  #5  ERIE  a. 1.0  ONTARIO  cr  »-r  c  - O V*  (3  1940  Z D  OKANAGAN''  g  .£  ~  WOOI  CO 0,1  HURON  OLIGOTROPHIC ,01'  1  1 — i — i i i i 11  1  1  1  i i i i i i 11 z / t w = qs  Figure 1.  i  i i ' ' 'iti  10  i  ' i i i i 11  100 •  The relationship (Vollenweider,1968) between trophic state, annual total phosphorus load, mean depth (z) and flushing time ( t ) shown for some Canadian lakes. Kamloops Lake is not plotted due to the difficulties discussed in the text, (from St. John et a l . 1976) w  1000  3  of how much phosphorus detrital apatite contributes to the nutrient budget of a lake remains controversial. If apatite phosphorus is largely unavailable for biological growth (or of very limited availability), it should not be included in the total phorus loading values  used to  estimate trophic state.  recognized by Dillon and Kirchner (1975), Peters himself (Vollenweider, 1968).  phos-  This problem was  (1978),  and Vollenweider  Dillon and Kirchner (1975, p. 143) summarized  as follows: "However there will undoubtedly be certain cases where total phosphorus is not the most suitable fraction to work with; for example, some streams may carry a high total phosphorus content that  is  largely the result  of erosion of apatite-bearing rock. soluble  phosphorus  may  important consideration.  be  In these cases,  biologically  a more  Such a condition exists in  the Rhine as described by Vollenweider (1968)." Fluorapatite is a common accessory mineral in the source rocks for the glacial  debris supplying sediments to many Canadian lakes.  the subject of the present study, is a 25 km x 2.1 cupies a glacial  km fjord lake which oc-  valley in the semi-arid, south-central  Columbia (Figure 2).  Kamloops Lake,  region of British  Chemical analyses of water and sediment in the lake im-  ply that 70% of the total phosphorus entering the lake is in the form of apatite and that apatite may occur in all size fractions of the lake sediment (St. John et j}].., 1976).  This latter suggestion is significant, for if apa-  t i t e is present in the lake as particles smaller than 0.45 pm, apatite particles could pass through the membrane filters  used to separate  "dissolved"  from "particulate" materials and be included in the "dissolved" phosphorus  4  depth >120m  i . . . . i • •i • i 0 5 10  km  Figure 2.  Sample location in Kamloops Lake, British Columbia, Canada.  Sediment 0.5 g  0.22 M Na C I T R A T E 0.11 M Na B I C A R B O N A T E 1.0 g Na DITHIONITE  Residue  Extract  1 M NaOH  1 Extract  Residue  Colourimetric \ Determination/  (  0.5 M HCI  Extract Res due discarded APATITE  Figure 3.  P  NON-APATITE INORGANIC P  The selective chemical extraction scheme for identification of apatite phosphorus and Non-Apatite Inorganic Phosphorus developed by Williams et al_. (1976). N.W.R.I. used 1M HCI, rather than 0.5M HCI, to extract apatite phosphorus from Kamloops Lake sediments, as discussed in text.  5 pool.  Therefore, estimates of productivity could be erroneous even i f dis-  solved rather than total  phosphorus values are used for the estimation,  suggested by Dillon and Kirchner (1975).  as  Both Williams et aj_. (1976) and  Smith et al_. (1978) state that the solubility of apatite increases with decreasing particle size, but no estimates have been made of the availability of phosphorus in apatite that is smaller than 0.45 pm. The method used to identify apatite in the 1976 Kamloops Lake study was the selective chemical extraction technique of Wil 1 iams et a]_. (1976) (Figure 3). (DCB)  In this  procedure, sodium dithionite-sodium citrate-sodium bicarbonate  and NaOH release phosphorus associated  plexes.  with iron and aluminum com-  The amount of orthophosphate released is determined colourimetrical-  ly in a reaction involving the formation of molybdophosphoric acid.  The sum  of the DCB and NaOH phosphorus is referred to by Williams et a l . (1976) as Non-Apatite Inorganic Phosphorus (NAIP).  Apatite phosphorus is then released  as orthophosphate by dissolution of the apatite in 0.5 M HC1, and the orthophosphate is again measured colourimetrically. associated  with  specificity  of  the  There are, however, problems  colourimetric method for  orthophosphate (Harwood and Hattingh, 1973).  analysis  Complexes of silicate,  of  arsenate  and germanate can form heteropoly acids with molybdenum and interfere with the phosphorus determination. interfere.  In general,  Labile organic phosphorus compounds may also  the chemical extraction technique for  identifying  forms of phosphorus in soils and sediments has developed as a result of extracting standard compounds in the laboratory and from statistical  chemical  correlations (Fisher and Thomas, 1935; Williams, 1937; Dean, 1938; Williams, 1950;  Chang and Jackson,  1957;  1971a; Williams et al_., 1971b).  Williams et  1967;  Williams et  al.,  6 Direct methods for identifying and quantifying phosphate minerals in soils  and sediments have met with  quantities  of these minerals  limited success  and because of difficulties  determination (Lindsay and Vlek, 1977). a technique whereby  2  because of the small in petrographic  Shipp and Matelski (1960) developed  to 3 drops of 10.7 N  H2SO4  added to sediment on a glass  slide caused needle-like calcium sulphate crystals to grow on the surface of apatite grains, thereby facilitating their recognition. H 2 S O 4  however, carbonate minerals also develop this  In the presence of  needle-like  growth and  differentiation of the carbonates from the apatites is based on a difference in birefringence.  Shipp and Matelski  apatite  profile in Nebraska and correlated the results with the  in a soil  acid soluble section".  (1960) used this method to quantify  phosphorus in a profile in an "adjacent quarter of the same  The correlation would be more convincing i f the measurements were  made on samples from the same locality.  Sawhney (1973) used the electron  microprobe to examine the composition of phosphate grains, but his work is not  quantitative.  detecting  Kingston  and quantitatively  (1973,  p . l ) examined  estimating  sediments by mineralogical methods".  minerals  in lacustrine  Kingston concentrated phosphate grains  by heavy liquid and magnetic separations could be used effectively  phosphate  the "feasibility of  and suggested that the microprobe  to obtain particle  size distribution,  relative  abundance, and mineralogy of discrete phosphate grains. However, Kingston's method is not quantitative. The purpose of the present study was to develop a method of physical separation, identification and quantification of apatite  in lake sediments  and to use this method to investigate the size distribution of apatite in Kamloops Lake.  The apatite  concentrations  of various  size  fractions of  Kamloops Lake sediment obtained by this method of direct observation would be  7  compared to the apatite  concentrations  obtained by the selective chemical  extraction of the same size fractions.  In addition, an attempt would be made  to  which  estimate  the  amount  of  apatite  "dissolved" phosphorus load of the lake.  may  be  contributing  to  the  8  METHODS  Physical Separation, Identification and Quantification of Apatite  A sample of sediment was collected with a Shipek Grab Sampler from the basin floor of Kamloops Lake at a depth of 130 m in the pro-delta the  Thompson River Delta at the  east end of  the  lake  region of  (Figure 2).  The  particle size distribution of the total sediment was determined by hydrometer analysis. urn.  The sample was divided into eight size fractions from 125 ym to <2  The 125 to 62 urn fraction was obtained by sieving, the five  fractions  between 62 and 10 urn by separation in a hydraulic cyclone elutriator Appendix 1) and the 10 to 2 and <2 ym fractions by centrifugation.  (see  Sedigraph  analyses of the 6 fractions from 62 to 2 pm were performed by the National Water Research Institute,  (formerly the Canada Centre for Inland Waters) West  Vancouver. Each of the eight size fractions was further subdivided on the basis of density by separation with heavy liquids.  As seen in Figure 4, 250 mg of  sediment were centrifuged in 50 ml of diiodomethane to remove the particles with density >3.3 g.cm"3.  The light particles from this separation were then  centrifuged in 50 ml of an acetone diiodomethane mixture with a density of 3.05 g.cm"3.  Apatite was concentrated in the heavy fraction, which will be  referred to as the apatite between 3.05 3.199  g.cnr^  and 3.3  fraction and contains  g.cm~3.  (McConnell,  The theoretical  1973);  however,  minerals with densities  density  isomorphous  of fluorapatite  is  substitutions  in  naturally occurring "fluorapatites" result in a range of densities from 3.1 to 3.2 g.cm"3 (Berry and Mason, 1959).  Densities  of some igneous apatites  reported by McConnell (1973) range from 3.17 3.22 g.cm"3.  Sediment 1.5 kq  r  r  1  t  125-52  62-4 5  4533  "I treated similarly  33-25  " r -250 r^— rr.fin ' CH I 2  2  3.3 • g c m"  3. Heavy  Light'] CH I 2  17-10  10-2  ^ r treated similarly  2 50 mg CH I  I  2  gem i:  2  - 3  j Heavy /Including APATITE & VF^ONAZITE  x  2  3.0 5 g c r r f  [Tight  r  T 25-17  3  1 Heavy| /Including \ APATITE  Figure 4.  Figure 5.  Scheme for heavy liquid separation of apatite.  Identification of phosphate grains using a scanning electr microscope equipped with an energy dispersive X-ray spectrometer. Bar in (A) and (B) is 500 uin long. (A) S.E.M. image. Apatite grains are circled. (B) Phosphorus K image. a  10 The  separation  procedure described  above was  followed  for all  fractions of the Kamloops Lake sediment except the <2 ym fraction. of  size  Because  the very long centrifugation times required for separation of the <2 ym  fraction, only the 3.05 g.cm"^ separation was done. of  the  separation  procedure  is  presented  A detailed description  in Appendix 2.  Triplicate or  quadruplicate heavy liquid separations of the 5 size fractions from 62 to 10 ym were  performed;  single  separations  were  done  for  the  other  3  size  fractions. A subsample  of  each  apatite  fraction  obtained  by the  heavy  liquid  separation was mounted on a graphite disc and examined at low magnification with an ETEC autoscan scanning electron microscope equipped with an ORTEC X-ray analytical system.  The procedure for the S.E.M. sample preparation and  examination is outlined in Appendix 3.  Grains in the apatite fraction which  contain phosphorus are easily identified in the X-ray image of the phosphorus K  a  emission,  as  shown  in  Figure 5.  Once identified,  the  phosphorus-  containing grains may be examined individually at increased magnification and their elemental compositions determined from their X-ray emission spectra. Since the grains in each sample are approximately equivalent in size and density,  the number of grains containing phosphorus divided by the  number of grains in any one S.E.M.  total  ' f i e l d ' , such as that of Figure 5, is a  measure of weight per cent apatite in that particular apatite fraction. For each apatite fraction, five fields, each containing approximately 100 to 200 grains, were examined.  The five apatite concentrations from the five  fields  were averaged to obtain a value representing the apatite concentration in the apatite fraction.  This number was multiplied by the weight proportion of  sample  by the  represented  apatite  fraction to  obtain  concentration of apatite in the original size fraction.  a measure  of  the  11 Since  the  heavy  liquid  separation  of  fine-grained  sediment  may be  incomplete, a weighed amount of fluorapatite of appropriate size was added to each of the five  size fractions  from 62 to 10 ym as an internal standard  ("spike") to test the recovery of apatite  in the apatite  fraction.  The  apatite used for this internal standard was a single inclusion-free crystal of fluorapatite from Durango, Mexico (Sample S-4024, obtained from J . Nagel, U.B.C).  The apatite crystal was crushed and separated into the five size  fractions by gravity settling and decantation. for  these 5 size  fractions,  triplicate  unspiked samples  or quadruplicate analyses  liquid separation and S.E.M. examination) performed.  As in the  (heavy  of the 5 spiked fractions were  As seen in equation 1, K b, the mean concentration of 0  apatite  observed in the spiked sample should be equal to a recovery factor, p, times the amount of apatite sediment (M). equal  added (I)  plus p times the apatite  in the original  However, since p times the apatite in the original sediment is  to M b» the mean value observed for apatite 0  in the unspiked sample  (equation 2), the two equations can be combined to solve for p.  K b = Pi + pM 0  But  pM = M so p =  (1) (2)  o b  l<ob -M b 0  , , (3)  I  Analysis  of  apatite  from Durango, Mexico which  U.S.G.S. are reported by Young et aj_. (1969).  were  performed  The density of the -3  analyzed by Young et al_. (1969) was 3.216 g.cm .  by  the  apatite  12 Selective Chemical Extraction of Apatite  Selective chemical extractions of apatite for this study were performed by the National Water Research Institute,  West Vancouver.  N.W.R.I. modified  the extraction scheme of Williams et aj_. (1976), Figure 3, in that 1 M HCI, rather  than 0.5  verification  of  M HCI, was the  technique  used  for  using  the  apatite  apatite  extraction.  standards  was  Initial  followed  by  extraction of seven of the size fractions of Kamloops Lake sediments. Verification  of the  selective chemical  extraction  technique  involved  extraction of an apatite standard, extraction of sediment with apatite added as an internal standard, and S.E.M. examination of the extracted  sediment.  The apatite used as the standard was the same crushed fluorapatite from the single crystal from Durango, Mexico which was used in the physical separation spiking procedure.  Analyses of apatite from Durango by Young et al_. (1969)  suggest that impurities in the apatite are less than 1.5 weight per cent and that phosphorus comprises 17.8 weight per cent of the apatite.  13 ANALYTICAL RESULTS  Physical Separation Particle  size  distributions  for  the  fractions are shown in Figures 6 and 7.  total  sample  and  for  6  size  The weights of each of the three  density fractions obtained by heavy liquid separation of each size fraction are summarized in Appendix 4, grains  in the apatite  and the  results  of  point  counting  fraction with the scanning electron  apatite  microscope are  summarized in Appendix 5. Four typical  phosphorus-containing grains identified  in Kamloops Lake  sediment are shown in Figure 8.  The phosphorus-containing grains observed in  all  exception  size  fractions,  with  one  which will  be  discussed  later,  contained both Ca and P in proportions equivalent to those observed in an apatite  standard.  Some grains have X-ray emission  spectra  indicating the  additional presence of minor amounts of A l , S i , and/or Fe, which are probably present as coatings on the apatite as the grains were not treated to remove sesquioxides. in  the  <10  The numbers of grains with these coatings ym  sizes.  A typical  X-ray  increased slightly  emission  phosphorus-containing grains is shown in Figure 9.  spectrum  for  the  The X-ray energy from  fluorine is not detected by the X-ray emission method used. The observed  apatite  reported in Appendix 6.  concentrations  calculated  for  each  sample  are  Observation with the scanning electron microscope  showed that the "125 to 62 ym" fraction contains a large proportion of grains smaller than 62 ym.  When point counting grains in the apatite fraction of  this  only grains  size fraction,  counted.  of  approximate  size  125 to  62 ym were  14 100-  O 8 0  o  CI  0.  60-  a 3 40  E 3  o 101  - ' 1  Figure 6.  , 2  Equivalent  ,  ,  10  17  Spherical  1—,—, 23  33  Diameter,  45  ,  ,  62  10 0  jum  Hydrometer analysis showing particle size distribution of sediment from the pro-delta region of Kamloops Lake.  100-  § 80-  D C  o  B  A  0.  V >  60-  3 40-  E  3  o 20-  2  Equivalent  Figure 7.  10  Spherical  17  25  33  Diameter,  tS  62  10 0  um  Sedigraph analyses showing particle size distribution of 6 size separated fractions of sediment from Kamloops Lake. Analyses performed at N.W.R.I. A = "62 to 45 ym" fraction B = "45 to 33 ym" fraction C = "33 to 25 ym" fraction D = "25 to 17 ym" fraction E = "17 to 10 ym" fraction F = "10 to 2 ym" fraction  15  16 Heavy  liquid  separation  and  S.E.M.  examination  of  the  five  size  fractions of both unspiked and spiked samples from 62 to 10 urn were performed in  triplicate  or  quadruplicate.  The  observed  apatite  concentrations  calculated for these repeated analyses (Appendix 6) were averaged to obtain a mean observed apatite concentration for each of the five fractions. mean concentrations  (Mo^ and K h) are summarized in Table 1.  These  The relative  0  standard error of each mean observed apatite concentration is generally about 5%.  This error reflects  differences  between subsamples  and variability in  estimates of the weight per cent apatite in the apatite fraction. The mean observed apatite represents  concentration, M b, of the unspiked sample  the amount of apatite  separation of apatite  is  0  in the size fraction i f the heavy liquid  100% complete.  However, complete  separation of  fine-grained sediments is unlikely and the means of the spiked and unspiked samples for each size fraction were substituted the  recovery  factor,  p.  The observed  in equation 3 to calculate  apatite  concentrations  of  the 5  unspiked samples were then corrected for incomplete separation in order to estimate the amount of apatite in the original size fraction (M, Table 1). Recovery of apatite  in the apatite  decrease with decreasing grain size.  fraction  (p, Table 1) is  seen to  The relative standard errors of the  recoveries, and consequently of the corrected apatite concentrations (M), are about 20%.  However, the minimum apatite concentration for any size fraction  is that observed in the unspiked fraction (Mq^). No attempt was made to quantify the apatite point  counting  containing  phosphorus-containing  grains  smaller  than  grains.  1 ym by X-ray  in the <2 ym fraction by Detection  of  spectrometry  phosphorusis  extremely  difficult since there is very l i t t l e X-ray emission from these tiny grains.  17  TABLE 1  Sample  Apatite Concentrations from Physical Separation Method  "ob ng.g -1  K  ob, wg.g-'  ug.g-'  ug.g-  125-62 m  1180 (single observation)  62-45 iim  7080±320  U430±590  4616  0.94±.15  7500*1400  45-33 ym  4600±180  7280±530  2795  0.96+.20  4800*1100  33-25 urn  3430±130  6220±210  3401  0.82±.07  4200±500  25-17 vm  3260±240  5350*610  2699  0.77±.24  4200±1500  17-10 pm  2220*200  3790±150  2264  0.69*.11  3200*500  10-2 urn  1030 (single observation)  v  Note:  Numbers are not rounded to 2 significant figures until the final calculation (H).  H jj« Mean observed apatite concentration of unspiked sample (from Appendix 6), ± the standard error of the mean. 0  ^ob° ^ean observed apatite concentration of spiked sample (from Appendix 6), ± the standard error of the mean. I» Amount of apatite added as an Internal standard. p» Recovery factor, calculated using equation 3 in text, ± the calculated standard error. M* Apatite concentration in the size fraction, corrected for Incomplete recovery of apatite 1n the apatite fraction, * the standard error. H « Mt>/P 0  18 Since  only  a  3.05  g.cm"3  density  separation  was  attempted  for  this  fraction, the apatite in the <2 ym fraction was less concentrated than in the apatite  fractions  for  the  other  grain sizes.  Two phosphorus-containing  grains from the <2 ym fraction which have dimensions approaching 0.45 ym are shown in Figure 10.  Monazite is a cerium, lanthanum phosphate with small  amounts of thorium and yttrium. and La. 11.  Calcium substitutes in minor amounts for Ce  The X-ray emission spectrum of a monazite grain is shown in Figure  Monazite has a density of 4.6 to 5.5 g.cm"^ and so would not be included  in the apatite fraction (3.05 to 3.3 g.cm"3) of the other sizes.  Monazite,  like apatite, is an accessory mineral in igneous and metamorphic rocks and, again like apatite, has an extremely low solubility and is unlikely to be an important source of biologically available phosphate.  Chemical Extraction  The  results  presented  of  the  chemical  in Tables 2a and 2b.  extraction  of  apatite  The phosphorus content  standards of  the  are  apatite  standard was assumed to be 17.8%, as measured in fluorapatite from the same locality by Young et a l . (1969).  Errors involved in weighing the apatite are  less than 0.5%. Recoveries of pure apatite ranged from 86 to 97%, with 2 to 5% of the apatite being extracted as Non-Apatite Inorganic Phosphorus (see Table 2a). Theoretical 102% (see  recoveries Table 2b).  apatite extract apatite values.  values  of apatite  in the spiked sediment  However, the is  standard error of  about 3%, and the theoretical  added may be exaggerated  by errors  in the  ranged from 75 to the  mean sediment  recoveries  spiked  of the  and unspiked  A spiked and an unspiked sample of 62 to 45 ym sediment from  19  15  Figure 10.  Apatite and monazite grains with dimensions approaching 0.45 ym are circled. Bar in (A) and (B) is 0.45 ym long, (A) Apatite (B) Monazite  O to O  ii  ho 't....  -f  H  -t  1  I  1  I  10  I  15 Energy,keV  Figure l l .  X-ray emission spectrum for Kamloops Lake monazite.  20  TABLE 2a Extraction of an Apatite Standard  Apat1te-P ug  NAIP-P x 100 Initial Ht.P  NAIP-P ug P  Initial Wt. ug P  Apatite Size  Apatlte-P x 100 Initial Wt.P  All sizes  2081  105  51  1800  861  10-2 um  2183  85  41  2100  961  25-17 urn  2096  2000  951  33-25 uM  2580  2500  971  TABLE 2b  Sample  Not extracted 54  21  Extraction of Apatite from Spiked Sediment Samples  U Unspiked Sample ( g ap-P).(g sed.)" v  1  I Amt. Ap. Added (ug ap-P).(g sed.)"  1  S Spiked Sample (ug ap-P).(9 sed.)"  1  Recovery of Apatite Spike (Assumes 31 error In S and U) M x 100  KT Gen 1A (AP)  549  143  696  102I±18I  KT Gen 1A (AP+IP+OP)  549  148  660  751±181  1293  821  2017  881±91  (CAM 62-45 um (AP)  21 Kamloops Lake were  separated  with  heavy  liquids  (as  above)  after  being  extracted for apatite and NAIP and were examined with the scanning electron microscope.  No apatite  indicating that general,  the  all  grains  were  observed  in  of the apatite was dissolved  Williams  et  aQ_.  (1976)  technique  the  apatite  in the extraction. of  selective  chemical extraction of apatite seems to be >85% effective fluorapatite standard. generally  fraction, In  chemical  in recovering a  WiIdung et aj_. (1977) found that the Williams method  gave recoveries  of >90% of  inorganic phosphorus added to  lake  sediments. The results of the apatite extractions of the seven size fractions of Kamloops Lake sediment  are summarized in Table 3.  The concentration of  apatite is the concentration of apatite-phosphorus divided by 0.18, since the weight per cent of phosphorus in apatite is approximately 18%. The apatite concentrations indicated by chemical extraction are plotted against those of the physical separation in Figure 12. similar results  The two methods give  (within 7%) for the five size fractions from 62 to 10 pm.  The 10 to 2 pm point count value is considerably lower than the extraction value since this sample was not spiked to estimate recovery of apatite in the apatite fraction. Since the point count value for the 10 to 2 pm sediment has not been corrected for incomplete separation and is too low, the chemical extraction numbers are plotted in Figure 13 to estimate the concentration of apatite in sediment smaller than 0.45 pm.  Extrapolation of the extraction data suggests  that this concentration may be as high as 1800 pg apatite per gram sediment. Therefore,  apatite  smaller  than  0.45  pm probably  "dissolved" phosphorus load in Kamloops Lake.  contributes  to  the  Data are not available to  calculate how much this apatite is contributing to the "dissolved" load, but estimates (see Appendix 7) suggest that it is about 20%.  TABLE 3  Sample  Extraction of Apatite from Kamloops Lake Sediments  Mean Cone. Ap.-P t Std.Error pg.g  Mean Apatite Cone. ± Std.Error pg.g T  62-45 urn  1293±13  7180±72  45-33 pm  912±57  5070±318  33-25 pm  738*19  4100±105  25-17 pm  756±19  4200±105  17-10 pm  607±11  3370±61  10-2 pm  571±23  3170±128  <2 pm  352±26  1960*144  23  c .2 800CH  o 00  >< UJ  62-45xjm 6000-  E o sz O  4 5 - 3 3 ;jm»y 25-17ijnV  4000-  y/%3-25 urn  C0  17X10 ijm  10-2 aim  o c 20 0 0o o o CO  <  Figure 12.  20'00  Apatite  40'0 0  c o n e , ojg-g  60'0 0 -1  8000  Physical  Separation  Correlation between apatite concentrations obtained by chemical extraction and by physical separation. Dashed line equals 100 per cent correlation.  24  .2 soooo  6000r-  O cn  40004  o o 2C0Oo o  0.45  10 Grain  Figure  13.  Apatite concentration grain size.  (by c h e m i c a l  Size  62 mr\  extraction)  versus  25  CONCLUSIONS  A method has  been developed  which shows that  the  concentrations  of  apatite obtained by indirect chemical extraction of phosphorus in Kamloops Lake sediments observation.  are comparable to the  values  obtained by direct physical  The method developed is time consuming, tedious, and expensive,  and is not recommended as a general procedure for evaluating concentrations of apatite in sediments.  Rather it is a method which could be used to verify  "apatite" concentrations from chemical extractions, and could, of course, be used for identification of other minerals as well. microscope with  energy  dispersive  X-ray  The scanning electron  spectrometer  has  proven  to  be  extremely useful and may be more versatile than the electron microprobe used in previous phosphate studies (eg.,  Kingston 1973)  scanning  than most  at  lower  magnifications  since  it  is capable of  microprobes.  The general  technique of using an internal standard to test the recovery of a mineral in heavy liquid separation was also an important part of this study. The apatite which has been observed in the sediments of Kamloops Lake accounts for a significant portion (approximately 70%, St. John et aj_., 1976) of the phosphorus in the total phosphorus load to the lake. summarized the  use  of  total  phosphorus measurements  in  In 1953, Kurtz soil  fol 1 ows: "Except for research studies, determinations of total phosphorus in soils have been made  rarely in  recent  years, since total phosphorus is generally recognized as of l i t t l e  value  in  assessing  f e r t i l i t y of a soil." (Kurtz, 1953,  the p.61).  phosphorus  science  as  26  Total  phosphorus measurements  in lakes  receiving  sediment  from  glaciated  igneous and metamorphic terrains are similarly likely to be of l i t t l e  value  in assessing the "phosphorus fertility" of a lake. The results of this study indicate that apatite smaller than 0.45 ym may be abundant in Kamloops Lake, comprising as much as 20% of the "dissolved" phosphorus load.  The biological availability of phosphorus in apatite grains  smaller than 0.45 ym requires investigation.  27 REFERENCES  Berry, L . G . and B. Mason. 1959. Francisco, p.453-55.  Mineralogy.  W.H. Freeman and Co., San  Chang, S.C. and M.L. Jackson. 1957. Fractionation of soil phosphorus. Sci. 84:133-143  Soil  Cyclosizer, Operating Manual. 34p. Dean, L . A . 1938. An attempted fractionation Agricultural S c i . 28:234-246  of the soil phosphorus.  J . of  Deer, W.A., R.A. Howie and J . Zussman. 1966. An introduction to the rock forming minerals. Longman, London, p.504-509. Dillon, P . J . and W.B. Kirchner. 1975. The effects of geology and land use on the export of phosphorus from watersheds. Water Research 9:135-148 Fisher, R.A. and R.P. Thomas. 1935. The determination of the forms of inorganic phosphorus in s o i l s . J . of the Am. Soc. of Agronomy 27:863-873 Gakstatter, J . H . , M.O. Allum and J.M. Omernik. 1975. Lake eutrophication: results from the national eutrophication survey. Corvallis Environmental Research Laboratory, USEPA, Corvallis, Oregon. 32p. Harwood, J . E . and W.H.J. Hattingh. 1973. Colorimetric methods of analysis of phosphorous at low concentrations in water. _In Environmental Phosphorus Handbook. John Wiley and Sons. p.289-339. Jackson, M.L. 1956. Soil chemical analysis - advanced course. (Fifth Printing 1969) Published by the author, Dept. of Soil S c i . , University of Wisconsin, Madison, Wisconsin, p.101-168. K e l s a l l , D . F . , C . J . Restarick and P.S.B. Stewart. 1974. Technical note on an improved cyclosizing technique. Proc. Australas. Inst. Min. Metall. No. 251. p.9-10. Kingston, P.W. 1973. (unpubl.) Phosphate minerals in lacustrine sediments. Report of Contract No. KW111-2-0686/5-03-3040-101-0432 to Dep. Environ., Can. Cent. Inland Waters. 40p. Kurtz, L . T . 1953. 4: 59-88  Inorganic phosphorus in acid and neutral soils.  Lindsay, W.L. and P.L.G. Vlek. 1977. Phosphate minerals. Environments. Soil S c i . Soc. Am. Inc. p.639-672. McConnell, D. 1973. Apatite.  Agronomy  J_n Minerals in Soil  Springer-Verlag, New York. l l l p .  Peters, R.H. 1978. Concentrations and kinetics of phosphorus fractions in water from streams entering Lake Mepmhremagog. J . Fish. Kes. Board Can. ' 35:315-328.  28 Sagher, A . and R . F . H a r r i s . 1972. M i c r o b i a l a v a i l a b i l i t y of phosphorus i n lake sediments. A b s t r a c t s of 15th c o n f . on Great Lakes Research, p.193 • Sagher, A . , R . F . H a r r i s and D . E . Armstrong. 1975. A v a i l a b i l i t y . o f sediment phosphorus to microorganisms. Mater Resources Center, U n i v e r s i t y of Wisconsin Technical Report WIS WRC 75-01. 57p. Sawhney, B . L . 1973. E l e c t i o n microprobe a n a l y s i s of phosphates i n s o i l s and sediments. S o i l S c i . Soc. Am. P r o c . 37:658-660. Shipp, R . F . and R . P . M a t e l s k i . 1960. A microscopic determination of a p a t i t e and a study of phosphorus i n some Nebraska s o i l p r o f i l e s . S o i l S c i . Soc. Am. P r o c . 24:450-452. S m i t h , E . A . , C . I . M a y f i e l d and P . T . S . Wong. 1978. N a t u r a l l y o c c u r r i n g a p a t i t e as a source of orthophosphate for growth of b a c t e r i a and a l g a e . M i c r o b i a l E c o l . 4:104-117. S t . John, B . E . , E . C . Carmack, R . J . D a l e y , C . B . J . Gray, and C H . Pharo. 1976. The limnology of Kamloops Lake, B . C . Dep. E n v i r o n . , Inland Waters D i r e c t o r a t e , P a c i f i c and Yukon R e g i o n , Vancouver, Canada. 167p. S y e r s , J . K . , R . F . H a r r i s and D . E . Armstrong. 1973. lake sediments. J . E n v i r o n . Q u a l i t y 2:1-14.  Phosphate chemistry i n  V o l l e n w e i d e r , R . A . 1968. S c i e n t i f i c fundamentals of the e u t r o p h i c a t i o n of lakes and f l o w i n g waters, w i t h p a r t i c u l a r reference to nitrogen and phosphorus as f a c t o r s i n e u t r o p h i c a t i o n . P a r i s Tech. Rep. 0ECD, D A S / S C I / 6 8 . 2 7 . 192p. V o l l e n w e i d e r , R . A . and P . J . D i l l o n . 1974. The a p p l i c a t i o n of the phosphorus l o a d i n g concept to e u t r o p h i c a t i o n r e s e a r c h . N a t i o n a l Research Council A s s o c i a t e d Committee on S c i e n t i f i c C r i t e r i a for Environmental Q u a l i t y , NRCC#13690. 42p. Wildung, R . E . , R . L . Schmidt and R . C . Routson. 1977. The phosphorus status of e u t r o p h i c lake sediments as r e l a t e d to changes in l i m n o l o g i c a l c o n d i t i o n s - phosphorus mineral components. J . E n v i r o n . Q u a l i t y 6:100-104. W i l l i a m s , C H . 1950. Studies "on S o i l Phosphorus I . A method f o r the p a r t i a l f r a c t i o n a t i o n of s o i l phosphorus. J . of A g r i c u l t u r a l S c i . 40:233-242. W i l l i a m s , R.W. 1937. The s o l u b i l i t y of s o i l phosphorus and other phosphorus compounds i n sodium hydroxide s o l u t i o n s . J . of A g r i c u l t u r a l S c i . 27:259-270. W i l l i a m s , J . D . H . and T . Mayer. 1972. E f f e c t s of sediment d i a g e n e s i s and regeneration of phosphorus w i t h s p e c i a l reference t o Lakes E r i e and O n t a r i o . _In H . E . A l l e n and J . R . Kramer C e d . ] , N u t r i e n t s i n Natural . Waters, W i l e y - I n t e r s c i e n c e , New.York. p.281-315. W i l l i a m s , J . D . H . . , J . K . Syers and T.W. Walker. 1967. F r a c t i o n a t i o n of s o i l i n o r g a n i c phosphate by a m o d i f i c a t i o n of Chang and Jackson's procedure. S o i l S c i . Soc. Am. P r o c . 31:736-739.  29 Williams, J . D . H . , J.K. Syers, S.S. Shukla and R.F. Harris. 1971b. Levels of inorganic and total phosphorus in lake sediments as related to other sediment parameters. Environ. Sci. Technol. 5:1113-1120. Williams, J . D . H . , J.M. Jaquet and R.L. Thomas. 1976. Forms of phosphorus in the surficial sediments of Lake Erie. J . Fish. Res. Board Can. 33:413-429. Yeasted, J . G . and F.M.M. Morel. 1978. Empirical insights into lake response to nutrient loadings with application to models of phosphorus in lakes. Environ. Sci. Technol. 12:195-201. Young, E . J . , A.T. Myers, E . L . Munson and N.M. Conklin. 1969. Mineralogy and geochemistry of fluorapatite from Cerro de Mercado, Durango, Mexico. U.S.G.S. Prof. Paper 650-D. p.85-93.  30 APPENDIX 1.  The sediment  Cyclosizer into  five  is  Size Separation of S i l t Particles  a  hydraulic  specific  size  cyclone  fractions  elutriator from 62  which  urn to  separates  10 pm.  The  elutriation action takes place in a hydraulic cyclone where the fluid  is  spinning and centrifugal forces many times those due to gravity are acting on the particles (Cyclosizer, Operating Manual).  In a comparatively short time  (15 - 20 min.) the Cyclosizer is capable of yielding highly reproducible sub-sieve size divisions of sediment. (approximately 1974).  10 pm quartz)  Material rejected by the fifth cyclone  normally passes to  waste  (Kelsall  et  al.,  If this <10 pm material is needed for study, it may be decanted and  collected before the cyclosizing procedure. Approximately 430 grams of Kamloops Lake sediment from 62 to 10 pm were separated in the cyclosizer. removed by sieving  and the  Before cyclosizing, the >62 pm fraction was <10 pm fraction by settling  and decantation.  Thirty gram subsample.s of the sediment were cyclosized for 15 minutes, with a 3  1  water temperature of 11°C and a flow rate of 180 cm .sec" .  31 APPENDIX 2.  Procedure for Heavy Liquid Separation of Apatite.  For grain sizes from 62 to 2 ym, the following procedure was followed: 1.  Shake a dry sediment sample in a Spex Mixer for 20 minutes to homogenize.  2.  Add 0.25 g sediment to a Pyrex 50 ml conical centrifuge tube.  3.  Add 5 ml of  acetone,  which has been dried with anhydrous magnesium  sulphate, to the sediment  in the tube.  Disperse the sediment  acetone by hand swirling in an ultra sonic bath. the  acetone.  Discard  the  used  acetone.  in the  Centrifuge and decant  This  step  replaces  water  adsorbed onto grains with acetone, which is miscible with diiodomethane. 4.  Add 50  ml  of  diiodomethane  (density  3.32  Centrifuge for the appropriate time (Table 2-1).  3  g.cm" )  to  the  tube.  Stir the light fraction  from this separation with a thin glass rod to allow any heavy minerals to free themselves and settle. 5.  Centrifuge again. 3  Freeze the heavy fraction (density >3.3 g.cm" ) in the centrifuge tube by placing the lower half of the tube in liquid nitrogen. fraction  (density  <3.3  3  g.cm" )  into  a  second  50  Decant the light ml  Pyrex conical  centrifuge tube which contains 5 ml of dried acetone. 6.  Thaw  the  >3.3  diiodomethane  g.cm  -3  fraction.  remaining in the  Disperse  tube  this  and recentrifuge.  heavy fraction and add the light fraction from this light fraction of Step 5. 7.  fraction  in  the  Refreeze  the  separation to the  Save the heavy fraction.  F i l l the second centrifuge tube (Step 5) to 47 ml with diiodomethane. -3  This tube now contains 5 ml acetone (density 0.7899 g.cm ),  plus 42 ml  -3  diiodomethane (density 3.32 g.cm ) so that the solution has a density 3.05  3  g.cm" .  Centrifuge for the  fraction and recentrifuge.  appropriate time.  Stir  the  light  The heavy minerals from this separation have  32  densities fraction". 8.  3  between 3.05  g.cm"  3  and 3.3  g.cm" .  This  is  the  "apatite  -3  The lights have densities <3.05 g.cm .  Collect the 3 fractions  (the >3.3 g.cm  -3  fraction from step 6, and the  3  apatite fraction and the <3.05 g.cm" fraction from step 7) on preweighed 5.5 cm f i l t e r paper by vacuum filtration using a 47 mm Millipore 300 ml Pyrex funnel with stainless screen f i l t e r  support.  Freeze the  apatite  fraction in the bottom of the tube with liquid nitrogen while the <3.05 g.cm  -3  fraction is decanted.  the sediment and f i l t e r paper.  Use acetone to wash the diiodomethane from For grain sizes > 10 urn, use Whatman No.  1 Filter paper; for grain sizes between 2 and 10 pm use Whatman No. 42 f i l t e r paper. 9.  Preweigh the f i l t e r papers on a Mettler H20 balance.  Allow the f i l t e r papers and sediments to dry and then weigh on a Mettler H20 balance.  The time elapsed between preweighing the paper and weighing  the paper plus sediment changes in the  should be kept to a minimum since  laboratory may significantly  affect  humidity  the weight of  the  f i l t e r paper.  3  For grain sizes <2 pm, only the 3.05 g.cm"  separation is performed.  The  1.  Steps 1, 2, 3 as above.  2.  Add 5 ml of fresh dry acetone to the sediment from Step 3 and f i l l  the  procedure is as follows:  tube to 47 ml with diiodomethane.  Centrifuge, stir the light fraction  and recentrifuge. 3.  Collect the 2 fractions 3  g.cm"  fraction is  washed with acetone.  (>3.05 g.cm  collected  -3  -3  and <3.05 g.cm ).  on Whatman No. 42 f i l t e r  The <3.05  paper and is  However, this f i l t e r paper has a pore size of 1 to  2 pm and some sediment may pass through the paper.  Therefore, the >3.05  33 3  g.crrr fraction (in this case, the "apatite fraction") is collected on a preweighed 0.01 urn cellulose acetate membrane f i l t e r . is  soluble in acetone,  the diiodomethane is  first  Since this f i l t e r decanted from the  apatite fraction and 20 ml of acetone are added to the centrifuge tube. The sediment is dispersed in the acetone and is then centrifuged. acetone is decanted and water is added. filtered  through the 0.01  apatite fraction.  The water-sediment mixture is  pm membrane f i l t e r  paper to  collect  the  The weight of the apatite fraction may be determined  but no quantitative S.E.M. this size fraction.  The  point counting of apatite is  possible for  34  TABLE 2-1  Centrifugation Times for Settling Apatite in Diiodomethane or Diiodomethane-acetone Mixture, as in Appendix 2. IEC International Centrifuge, #240 Head  Minimum Particle Size  Centrifuge Speed RPM  Centrifugation Time Calculated Recommended  25 pm  900  0.86 min  2 min  17 ura  900  1.87 m1n  4 min  10 ura  900  5.39 min  10 m1n  2 im  1500  48.00 m1n  1 hr 40 min  0.2 ura  1500  75 nr.  NOTE:  Calculated centrifugation times, based on Stokes law, are given by Jackson (1956, p.127) as follows: (63.0 x 1Q8) (log t m 1 n  "  10  R/S) ( ) n  2  ' (Nm) (D )2 Us) u  where tg,in  " time 1n minutes  n  • viscosity 1n poises at the existing temperature (.028 for diiodomethane at 20°C)  R  • radius of rotation (In cm) of the top of the sediment 1n the tube (23cm for 50 ml centrifuge tube)  S  • radius of rotation (In cm) of the surface of the suspension in the tube (13cm for 50 ml centrifuge tube)  N,,,  » centrifuge speed in rotations per minute.  D  • particle diameter 1n microns  g  is  • difference 1n specific gravity between the particle and the suspension liquid (approximately 0.1 for both diiodomethane and di iodomethane-acetone mixture)-  Recoirmended centrifugation times are generous to allow settling of apatites with specific gravities from 3.1 - 3.25.  35  APPENDIX 3.  The  The Apatite Fraction: S.E.M. Sample Preparation and Examination.  amount of  apatite  in the  apatite  fraction  separation is determined by point counting apatite  of  the  heavy  liquid  grains in this fraction  with a scanning electron microscope equipped with an energy dispersive X-ray spectrometer.  The sample preparation and method of examination is described  below. 1.  Cut a pie shaped wedge (approximately one eighth of the f i l t e r paper) from the paper on which the apatite fraction of the separated sediment has been collected.  2.  Water wash the sediment from this wedge onto a 0.45 ym cellulose acetate membrane f i l t e r supported by the 13 mm diameter stainless steel of  a Millipore Vacuum filtration  apparatus.  Disperse  the  screen  sediment  evenly on the f i l t e r paper. 3.  Allow the 13 mm f i l t e r paper and sediment to dry and then use double sided  paper tape  to  mount the  paper on a circular carbon button  (diameter 13 mm, thickness 5 mm). 4.  Apply a carbon coat  (approximately 25 nm) to  the  filter  paper and  sample. 5.  Examine the sample with an ETEC autoscan scanning electron microscope with an ORTEC X-ray analytical system. 1.96  - 2.06  keV. Scan 5 fields,  Set the "region of interest" at  each containing 100 to 200 grains, in  the north, south, east, west and middle of each button. apatite grains in each field divided by the total  The number of  number of grains in  the field and multiplied by 100 gives an estimate of the weight per cent apatite in the apatite fraction. for  Average the weights per cent apatite  the five fields to obtain a single estimate of the weight percent  apatite in the apatite fraction.  36 APPENDIX 4.  Data from Heavy Liquid Separation.  The weights of each density fraction obtained by heavy liquid separation of  each size  fraction are summarized in Table 4-1.  sediment loss occurred during the separation procedure.  In general, 2 to 3% The weight per cent  of each sample which is represented by the apatite fraction is calculated by dividing the weight of the apatite fraction by the sum of the weights of the three density fractions.  This calculation assumes that the sediment loss  from each density fraction during separation is proportional to the weight of the fraction.  In sample 33-25 ym (subsamples 1,2 and 3), the <3.05 g.cm"3  separations spilt before being weighed, and the total sediment separated (E) 0  was obtained by assuming a 2% loss during separation.  37  TABLE 4-1  Sample  A Initial Wt.(g)  Data From Heavy Liquid Separation  3  Wt.<3.05g.ccT Fraetlon(g)  3  Wt.>3.3g.cm" Fraction(g)  Wt.apatite Fraction(g)  Wt.Total Sed. Sep.(g) (B + C + 0)  % Loss or Gain E-A x 100 A  Wt.* Apatite Fraction D x 100 E  125-62 pm  0.25831  0.24542  0.00294  0.00643  0.25479  -1.4  2.52  62-45 pm 1 2 3  0.25181 0.25385 0.25718  0.20006 0.21569 0.20070  0.02240 0.01996 0.02190  0.01955 0.02052 0.02157  0.24201 0.25617 0.24417  -3.9 +0.9 -5.1  8.08 8.01 8.83  62-45 pm (Spiked) 1 2 3  0.24360 0.21864 0.23004  0.20188 0.17861 0.18932  0.02095 0.01720 0.01843  0.02169 0.01800 0.01932  0.24452 0.21381 0.22707  +0.4 -2.2 -1.3  8.87 8.42 8.51  45-33 pm 1 2 3 4  0.25165 0.24928 0.26193 0.24674  0.21149 0.21761 0.23069 0.21643  0.01367 0.01034 0.01005 0.01093  0.01506 0.01819 0.01562 0.01502  0.24022 0.24614 0.25636 0.24238  -4.5 -1.3 -2.1 -1.8  6.27 7.39 6.09 6.20  45-33 pm (Spiked) 1 2 3  0.18169 0.25467 0.24560  0.15554 0.21766 0.21169  0.00812 0.01048 0.01006  0.01239 0.01722 0.01591  0.17605 0.24536 0.23766  -3.1 -3.7 -3.2  7.04 7.02 6.69  33-25 pm 1 2 3 4  0.24666 0.24901 0.24501 0.22805  spilt spilt spilt 0.19959  0.01049 0.00966 0.01005 0.01030  0.01612 0.01547 0.01401 0.01671  0.24173 0.24402 0.24010 0.22660  -2 assumed -2 assumed -2 assumed -0.6  6.67 6.34 5.84 7.37  33-25 pm (Spiked) 1 2 3 4  0.25940 0.24479 0.25472 0.24575  0.22401 0.21716 0.22796 0.21839  0.00910 0.01014 0.00657 0.00869  0.01702 0.01318 0.01345 0.01361  0.25013 0.24048 0.24798 0.24069  -3.6 -1.8 -2.6 -2.1  6.80 5.48 5.42 5.65  25-17 pm 1 2 3  0.23664 0.24425 0.25687  0.20550 0.21264' 0.22090  0.01067 0.00949 0.00927  0.01561 0.01843 0.01809  0.23178 0.24056 0.24826  -2.1. -1.5 -3.4  6.73 7.66 7.29  25-17 pm (Spiked) 1 2 3  0.22912 0.25073 0.24885  0.19873 0.22064 0.21342  0.01079 0.01241 0.01017  0.01756 0.01422 0.01643  0.22708 0.24727 0.24002  -0.9 -1.4 -3.5  7.73 5.75 6.85  17-10 pm 1 2 3  0.25598 0.25542 0.26694  0.23392 0.23531 0.23938  0.00959 0.00967 0.00818  0.01012 0.00972 0.00945  0.25363 0.25470 0.25701  -0.9 -0.3 -3.7  3.99 3.82 3.68  17-10 pm (Spiked) 1 2 3  0.26723 0.25574 0.26782  0.24192 0.23114 0.25131  0.00899 0.00944 0.00915  0.01155 0.01019 0.00827  0.26246 0.25077 0.26873  -1.8 -1.9 +0.3  4.40 4.06 3.08  10-2 pm  0.25204  0.24294  0.00260  0.01028  0.25582  +1.5  4.02  <2 urn  0.25299  0.22744  0.0O257  0.23001  -9.1  1.12  38 APPENDIX 5.  For each apatite  Data from S.E.M. Examination  fraction,  five  independent  fields  each  containing  100-200 grains were examined with the scanning electron microscope, in the north, west, south, east and middle of each button (except for one sample in the 17-10 pm size fraction and 3 samples in the spiked 17-10 pm size fraction in which only 4 independent fields were examined).  For each f i e l d , a measure  of  fraction  the weight  per cent  apatite  in the  apatite  is  obtained by  dividing the number of apatite grains observed by the total numbers of grains in the f i e l d .  The 5 results are averaged to obtain a mean weight per cent  apatite for each separation. The weight  The results are summarized in Table 5-1.  per cent apatite  numbers for each of the five  fields  are  uncertain in the first decimal place and therefore the average of these five numbers is accurate only to the first decimal place. reported to two decimal places  but the final  Data in Table 5-1 are  calculations  obtained using  these numbers are rounded to two significant figures (see Table 1).  TABLE 5-1  Data From S.E.M. Examination  Wt. % Apatite 1n Apatite Fraction  Sample North  West  South  East  Middle  4.03  5.56  4.92  5.61  3.23  4.67  7.75 12.23 8.49  6.96 10.86 6.59  10.38 6.82 9.35  7.47 6.55 8.41  9.25 5.79 10.79  8.36 8.45 8.73  62-45 nm (Spiked) 1 2 3  11.77 12.00 14.75  13.73 15.65 12.77  11.77 14.27 11.77  7.14 11.61 15.91  13.94 15.00 17.60  11.67 13.71 14.56  45-33 vm la lb 2 3 4a 4b  4.22 10.19 4.07 5.62 6.08 5.67  8.08 6.11 4.00 10.42 3.76 9.48  8.81 8.33 10.07 5.70 6.25 7.87  3.33 10.97 7.79 11.36 5.17 8.73  6.22 13.79 4.96 5.11 7.20 6.64  6.13 9.88 6.18 7.64 5.69 7.68  45-33 wm (Spiked) 1 2 3  12.14 10.35 7.69  11.06 11.96 8.76  8.33 12.37 10.19  9.52 10.97 10.44  12.78 11.43 9.63  10.77 11.42 9.34  33-25 um 1 2 3 4  3.37 5.18 4.73 5.71  5.88 6.31 5.21 6.28  6.79 4.45 4.87 3.14  5.45 5.23 6.79 5.28  2.78 5.76 6.75 5.21  4.85 5.39 5.67 5.12  33-25 ym (Spiked) 1 2 3 4  9.73 13.42 9.20 12.27  7.64 9.09 11.65 11.98  12.50 9.38 15.04 10.71  9.47 12.11 13.74 7.27  8.26 7.53 11.11 12.12  9.52 10.31 12.15 10.87  25-17 ym 1 2 3  2.45 4.58 2.91  7.46 4.73 6.79  7.14 2.96 1.65  6.59 4.08 4.79  3.57 5.26 3.20  5.44 4.32 3.87  25-17 ym (Spiked) 1 2 3  5.53 7.01 6.38  9.96 5.56 9.85  9.90 10.43 7.98  5.21 9.55 2.75  11.33 5.81 10.69  8.39 7.67 7.53  17-10 ym 1 2 3  4.49 4.52 5.89  4.94 6.10 5.09  12.50 4.88 3.72  5.48 7.64 3.97  4.88 6.81  6.46 5.78 5.10  17-10 ym (Spiked) 1 2 . 3a 3b  8.92 9.66 16.05 10.53  9.15 9.60 13.48 9.80  7.61 7.74 14.78 11.39  8.00 8.38 18.42 13.04  9.52  8.42 8.85 15.68 10.86  10-2 um  4.17  2.16  1.52  2.53  2.49  2.57  125-62 ym  Mean  62-45  40 APPENDIX 6.  The  numbers  involved  Observed Apatite Concentrations  in  the  calculation  concentrations are presented in Table 6-1.  of  observed  apatite  In three instances (45 to 33 pm,  subsamples 1 and 4; and 17 to 10 pm, subsample 3) a second sample for S.E.M. examination was prepared from a single apatite fraction in order to check an anomalously high or low calculated apatite concentration.  In these cases,  the  from  average  concentration  from  the  duplicate  analyses  separation was the value used with the concentrations other separations  a  single  calculated for the  of the same size fraction to obtain an average observed  apatite concentration for the fraction.  Explanation of Terms in Table 6-1  F=  Wt. of Apatite Fraction  as in Appendix 4.  Wt.% Ap in Ap. Frac.  Mean of 5 observations, as in Appendix 5.  Ob. Ap. Cone. =  Observed apatite concentration; Wt% Ap. in Ap. Fraction x F.  Av. Duplicate =  Average  observed  apatite  concentration  duplicate analyses of a single separation. average is used with the apatite from the repeated separations  of This  concentrations  to calculate the  mean for the size fraction. Std. Error of Mean =  Standard error (deviation)  of the mean observed  apatite  /n where x is  observed  concentration; JS ^ X  apatite  number of x's.  concentration  and n is  each the  41  TABLE 6-1  Observed Apatite Concentrations  Ob.Ap.Cone, ug.g-'  (Appendix 4)  Wt. X Ap. 1n Ap. Fraction (Appendix 5)  125-62 um  2.52  4.67  1180  62-45 um 1 2 3  8.08 8.01 8.83  8.36 8.45 8.73  6750 6770 7710  Sample  F X  62-45 um (Spiked) 1 2 3  8.87 8.42 8.51  11.67 13.71 14.56  10350 11540 12390  45-33 pm la lb 2 3 4a 4b  6.27 6.27 7.39 6.09 6.20 6.20  6.13 9.88 6.18 7.64 5.69 7.68  3840 6190 4570 4660 3530 4760  45-33 um (Spiked) 1 2 3  7.04 7.02 6.69  10.77 11.42 9.34  7580 8020 6250  33-25 pm 1 . 2 3 4  6.67 6.34 5.84 7.37  4.85 5.39 5.67 5.12  3230 3420 3310 3770  33-25 pm (Spiked) 1 2 3 4  6.80 5.48 5.42 5.65  9.52 10.31 12.15 10.87  6480 5650 6590 6140  25-17 um 1 2 3  6.73 7.66 7.29  5.44 4.32 3.87  3660 3310 2820  25-17 pm (Spiked) 1 2 3  7.73 5.75 6.85  8.39 7.67 7.53  6490 4410 5160  17-10 m 1 2 3  3.99 3.82 3.68  6.46 5.78 5.10  2580 2210 1880  17-10 pm (Spiked) 1 2 3a . 3b  4.40 4.06 3.08 3.08  8.42 8.85 15.68 10.86  3700 3590 4830 3340  10-2 pm  4.02  2.57  1030  Av. Duplicate ug.g" 1  Mean Ob.Ap Cone, pg.g"  Std. Error of Mean ug.g-^  7080  320  11430  S90  4600  180  7280  530  3430  130  6220  210  3260  240  5350  610  2220  200  3790  150  5015  4145  4085  42 APPENDIX 7.  Contribution of Apatite to the "Dissolved" Phosphorus Load.  Three stations in Kamloops Lake, each representative  of approximately  one third of the lake, have mean grain sizes of 10.2 ym with no sediment smaller than 0.45 ym, 4.2 ym with 4% of the sediment smaller than 0.45 ym, and 2 ym with 16% of the sediment  smaller than 0.45  personal communication).  phosphorus load to Kamloops Lake is 23  g.rrf^.y-  1  The total  (St. John et aj[., 1976).  "particulate" "dissolved"  phosphorus phosphorus  i.e. i.e.  ym (Dr. C H . Pharo,  2  90% of this load, or 20.7% g . r r f . y  >0.45 <0.45  ym and ym.  10% or  If  the  2  2.3  size  _1  is  g.m.~ .y-l  is  distribution  of  particulate phosphates is similar to that of the general sediment, 7% of the 2  true particulate matter may be <0.45 ym, and the loading of 20.7 g.m.~ .y""l would represent only 93% of the true particulate phosphorus.  In this case,  1.5 g.m."2.y-l of particulate phosphate <0.45 ym would be entering the lake. Approximately 80% of apatite;  however,  increases  with  the  the  particulate proportion  decreasing  sediment  phosphate of  in the  Non-Apatite  size.  If  total  Inorganic  35% of  the  sediment  is  Phosphorus particulate  phosphorus <0.45 ym is apatite (as indicated by extraction analyses of the <2 ym fraction by N.W.R.I.), this would represent a loading of 0.5 Therefore,  about 20% of the  so called "dissolved" phosphorus load of  2  g.m" .y"l may be particulate apatite. Cautionary Note:  2  g.m." .y-1.  This calculation is extremely approximate.  2.3  

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