British Columbia Mine Reclamation Symposia

Selenium status : Elk River Valley, BC 2009

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SELENIUM STATUS - ELK RIVER VALLEY, BC  Peter M. Chapman  Golder Associates 195 Pemberton Avenue North Vancouver, BC V7P 2R4 Tel 604-904-4005 e-mail;  ABSTRACT  The status of investigations into the effects (changes to a Valued Ecosystem Component [VEC]) or impacts (effects adversely affecting the utility or viability of a VEC) of selenium in the Elk River Valley, BC are reviewed. Previous studies focused on the abundant lotic (flowing water) habitats in the Valley and found limited effects (reduced sandpiper egg hatchability) but no impacts (overall sandpiper productivity higher than the regional norm). More recent studies have focused on less abundant high-risk lentic areas where selenium effects are more likely. Effects studies have been conducted with: red-winged blackbirds; various waterfowl species; Columbia spotted frogs; longnosed suckers. Based on studies conducted to date, current levels of selenium in the Valley do not appear to be having large-scale negative effects or impacts. However, some negative effects do appear to be occurring on a more localized level in some of the high-risk lentic areas. Studies are underway to assess whether or not there are population- level impacts in these lentic areas and, if so, their extent and significance. The possibility of management actions will be assessed accordingly.  INTRODUCTION  Selenium is a natural element, which is released naturally from selenium-containing rocks by weathering. Coal strata in the Elk River Valley contain selenium, whose release into the environment is accelerated by coal mining. Selenium, although essential for life, can be toxic at higher concentrations and can affect the reproduction of fish and of waterfowl and other birds feeding in waterbodies containing high levels of selenium.  Investigations are continuing in the Elk River Valley to determine whether or not fish and water bird reproduction is being effected by the selenium released from coal mining. Previous studies (EVMEMC, 2004) indicated that fish and water bird populations in lotic (flowing) environments, the streams and rivers that comprise the majority of the Valley aquatic environment, are not being impacted. Decreased hatchability has been documented in spotted sandpipers, but productivity remains above the regional norm (Harding et al., 2005). The lack of population-level effects is not surprising as coal mining releases the inorganic form of selenium; for this selenium to affect fish and water bird reproduction, it has to be in the organic form. Transformation of inorganic selenium to the organic form typically occurs in lentic (non-flowing) environments such as ponds, wetlands and lakes, not in lotic environments. More recent studies, summarized herein and reported in detail in EVSTF (2005) have focused on lentic environments in the Elk River Valley.  SELENIUM UPTAKE ROUTES  An assessment of selenium uptake routes in both lentic and lotic habitats focused on six lentic areas, three with elevated selenium levels, and three lotic areas, two with elevated selenium levels (Minnow Environmental, 2004a). Water, sediment, algae, plants, zooplankton, benthic invertebrates and fish were collected and analyzed. Stable isotope analysis (SIA), which measures distinctive signatures for carbon, nitrogen and sulphur related to an organism’s position in the food chain, was conducted (Orr et al., 2004).  The SIA study clearly showed that selenium uptake by organisms was greater in lentic than in lotic areas due to the enhanced biological transformation of inorganic selenium to organic selenium that occurs in these areas. These results confirm a long-standing hypothesis in the scientific literature (Simmons and Wallschläger, 2005). Specifically, uptake and cycling of organic selenium occurs via sediment-detrital pathways typical of lentic areas, but not of lotic areas. Benthic invertebrates in lentic areas had substantially higher tissue selenium concentrations than those in lotic areas. Thus, this study emphasized the importance of focusing on lentic areas where effects and possibly impacts from selenium are most likely to occur.  LENTIC (NON-FLOWING) MARSH BIRD STUDIES – RED-WINGED BLACKBIRDS  Red-winged blackbirds (Agelaius phoeniceus) nest in colonies in emergent vegetation in marshes and feed primarily on invertebrates such as insects and beetles in the marsh vegetation as well as the seed heads of certain marsh plants. Because marshes represent lentic areas that will tend to accumulate the toxic organic form of selenium, and these birds may accumulate selenium through their diet, studies were undertaken to determine any differences in productivity between blackbirds nesting in marshes with elevated selenium concentrations (exposed marshes) and marshes with background selenium concentrations (reference marshes) (SciWrite, 2004a).  At the high exposure sites (Clode Pond, Goddard Marsh, and a marsh in Line Creek below the Line Creek Mine – Figure 1), selenium egg concentrations were high enough that selenium toxicity might have been expected, based on thresholds reported in the literature for other species in other locations. Mean egg selenium (MES) concentrations ranged as follows for the low, intermediate and high selenium marshes (all values in micro-g/g dry weight): 3.7-5.3; 7.3-9.7; 6.1-20.6. Highest MES (micro-g/g dry weight) concentrations were in Clode Pond (15.1) and Goddard Marsh (20.6).  Both hatchability (proportion of eggs incubated to full term that hatched) and nestling survival (proportion of hatched eggs that survived to become fledglings) were assessed, as these are the most sensitive measures of selenium toxicity in birds. There was no difference between sites in the number of eggs laid (clutch size), nor in the proportion of eggs incubated to full term that hatched between sites. However, there were differences in nestling survival between sites; nestling survival was highest in the reference (low selenium marshes) and lowest in the high exposure marshes (highest selenium marshes). Surprisingly, nestling survival was higher at Goddard Marsh (100%) than at Clode Pond, despite higher (about 30%) selenium water concentrations in Goddard Marsh. Two of the Goddard Marsh embryos had visible abnormalities and one deformed nestling was recorded at Line Creek. No embryonic mortalities were seen at the other sites, including Clode Pond.  In addition to data on nestling survival, dead nestlings were seen at two of the high selenium marshes and at two of the low selenium marshes, but no dead nestlings were seen at the reference marshes. Again, surprisingly, no dead nestlings were seen at Goddard Marsh, but seven were seen at Clode Pond (36% of the nestlings in that area – the highest proportion recorded; the next highest proportion was three or 17% from a low selenium marsh). All of the dead nestlings were over a week old and appeared healthy, with no signs or trauma or malnutrition although their digestive tracts were empty. Elevated liver selenium concentrations (55 micro-g/g dry weight) suggested that selenium could have been a cause of death. Unfortunately data on selenium liver concentrations in live nestlings from the same nest as dead nestlings were not collected. And other causes of the observed mortalities, including predation on the young and on the adults feeding the young, and inclement weather, could not be excluded as possible reasons for at least some of the observed dead fledglings.     Figure 1. The Elk River Valley, showing the locations of the five coal mines, the federal-provincial water quality monitoring stations at Sparwood and at the Highway 93 Bridge, Goddard Marsh and Clode Pond.  A recent M.Sc. thesis (Vasterling, 2003) assessing the effects of selenium from phosphate mining in Idaho on reproductive success of red-winged blackbirds concluded that effects may occur when egg selenium concentrations exceed 20 micro-g/g dry weight. Such exceedances are presently occurring in both Clode Pond (maximum value 22.3 micro-g/g dry weight) and Goddard Marsh (maximum value 24.6 micro-g/g dry weight) (SciWrite, 2004a). LENTIC (NON-FLOWING) WATER STUDIES – WATERFOWL  In addition to the red-winged blackbirds lentic effects studies, similar studies were also conducted on waterfowl in 2003 and 2004 (SciWrite, 2004b). Unfortunately, the work was only moderately successful for several reasons. First, only a low number of waterfowl nest in the marshes. Second, it was extremely difficult to find nests – adult birds are very effective at hiding their nests from potential predators including humans. Third, young waterfowl leave their nests immediately after hatching, precluding the possibility of linking each brood with a specific nest from which an egg was taken for selenium analysis.  In 2003 a total of three eggs were collected, two from areas with high selenium levels. In 2004 a total of 26 eggs were collected from 19 active nests, and 50 broods of eight species of waterfowl were counted: American coot, hooded merganser, mallard, blue-and green-winged teal, ring-necked duck, Canada goose, Barrow’s goldeneye, bufflehead. Sampling sites were the same as those for the red-winged blackbird study.  Highest egg selenium concentrations were measured in an American coot egg from Clode Pond (34.7 micro-g/g dry weight); selenium egg concentrations were generally highest in the marshes with highest water selenium concentrations, with the exception (again) of Goddard Marsh. Selenium concentrations were high enough that toxicity might have been expected, based on threshold levels reported in the literature for different species in other areas. Because only Canada goose and mallard eggs were collected at more than two sites, the data set was not robust enough for statistical comparisons. In fact, given the fact that the potential breeding population at each marsh was only about six or seven successful pairs, virtually all of them would have had to be found and sampled and the broods linked to specific nests (for example, by radiotelemetry) to generate adequate sample sizes for statistical analyses.  Based on the limited data obtained, there was no evidence of adverse effects due to selenium (e.g., no mortality, no abnormalities), and no differences in productivity between waterfowl from areas with elevated selenium levels compared to those from reference areas. Clutch and brood sizes for all waterfowl were within or above the normal ranges for BC at all sites and did not differ between marshes with high selenium and reference marshes. However, the three high exposure sites were poorly represented in the brood counts. Again, Goddard Marsh results were surprising for the low selenium concentrations in eggs – as the authors noted “this site seems to be an outlier in terms of selenium uptake in waterfowl” despite having the highest selenium water levels of any of the lentic sites assessed. Clode Pond also provided a surprise in that there were no nesting ducks although the habitat and food supply were more than adequate for such activities. However, at least one brood of goslings was raised in Clode Pond, and one brood of coots hatched there.  LENTIC (NON-FLOWING) WATER STUDIES – LONGNOSE SUCKER AND SPOTTED FROGS  Aquatic lentic effects studies focused on a fish (longnose sucker) and an amphibian (Columbia spotted frog) in Goddard Marsh and a reference site (Minnow Environmental, 2004b). Goddard Marsh was chosen for study because of its very high water and biota selenium concentrations. Despite elevated selenium concentrations, the marsh remains productive, supporting many species of birds, fish, amphibians and invertebrates. Similar studies could not have been conducted at Clode Pond, which consists of three small, interconnected ponds that were constructed to control sedimentation during mining. The only fish found in Clode Pond are cutthroat trout; effects studies with this species from the Pond will be conducted in 2005.  Both the sucker and the spotted frog were chosen for study based on a previous reconnaissance study of lentic areas (Minnow Environmental, 2003). The study focus was on species that were resident in lentic areas and, in the case of high selenium areas exemplified by Goddard Marsh, most likely to demonstrate adverse effects from selenium. The overall approach was to follow the development of fertilized eggs using incubation boxes within the marsh and in a reference area.  However, as the study progressed, it was discovered that adult longnose suckers in Goddard Marsh were smaller than normal, leading to the conclusion that these suckers are a dwarf variety, which spawns at a different time, producing less and smaller eggs than the non-dwarf variety. (Genetic determinations to establish whether or not this is a different species of sucker are currently being conducted). As a result, there were problems obtaining sufficient breeding adults and thus sufficient fertilized eggs. In total, three females from Goddard Marsh (including one used to refine the test methods) and five females from the reference area were found in ripe, pre-spawning condition. In addition, when dwarf suckers were spawned and eggs were fertilized with sperm, the incubation containers proved inadequate (mesh size was too large for dwarf eggs) and fungus growth and sedimentation killed many eggs. Of 6,687 fertilized and incubated eggs, only 94 larvae emerged from the incubation containers – 56 from five females from a reference area and 38 from a single female from Goddard Marsh. The sucker eggs from Goddard Marsh did have higher selenium concentrations than those from the reference area, and the data are suggestive of more deformities in Goddard Marsh larvae than in those from the reference area. However, because of the small sample size and other problems noted above, no definitive conclusions are possible.  There were also problems, though different ones, with the frog study. No frog egg masses were found in the reference area despite extensive searches, and only three viable egg masses were found in Goddard Marsh. As a result, there are no reference data for comparison. Thus, although frog deformities were noted and there was a positive correlation with elevated selenium egg concentrations, causation could not be established. There are other factors than selenium that can cause frog deformities, for example virus infections, ultraviolet light irradiation. Again, the data are suggestive but not definitive that selenium may be causing some deformities in frog tadpoles in Goddard Marsh.  FUTURE STUDIES  Studies being conducted in 2005 include:  • Mapping of aquatic lentic and lotic habitats to ensure that representative areas are being assessed and to provide the basis for evaluating the significance of any localized impacts to the overall health of the Elk River Valley aquatic ecosystem. • Monitoring water quality to provide early warning of increased selenium concentrations and loadings. • Additional lentic effects studies with red-winged blackbirds to determine whether selenium is in fact responsible for the effects observed in 2004, and the extent and significance of any such effects. • Additonal lentic effects studies with longnose suckers and Columbia spotted frogs, building on the information collected in 2004 to determine whether selenium is in fact adversely affecting reproduction of these species in Goddard Marsh. • A lentic effects study with cutthroat trout in Clode Pond to determine if there are any reproductive effects to this species in that highly selenium-enriched environment. Previous studies with this species in lotic environments have not indicated any effects.  CONCLUSIONS  Based on the studies conducted to date, current levels of selenium in the Elk River Valley do not appear to be having large-scale negative effects or impacts. An effect becomes an impact when it adversely affects the utility or viability of a valued ecosystem component (VEC). For instance, reduced hatchability of sandpipers is not an impact because productivity is not affected, i.e., number of young produced remains high, in fact higher than the provincial average. If productivity were reduced, then this would be an impact. Studies in 2005 will determine whether there are impacts to red-winged blackbirds and whether there are effects / impacts to fish and frogs living in high-risk lentic areas with high levels of selenium.  Table 1: Summary of effects studies conducted to date in lotic and lentic areas of the Elk River Valley  SPECIES EFFECT? IMPACT? COMMENTS LOTIC Cutthroat trout No No Additional studies underway in Clode Pond, a lentic area American dipper No No Spotted sandpiper Yes No Sandpiper hatching success depressed but productivity high; further studies recommended if water selenium concentrations increase LENTIC Red-winged blackbirds Yes Uncertain Nestling survival decreased at some high- selenium sites; other factors than selenium may have contributed to mortalities at some sites, embryo abnormalities at one site, one deformed nestling at another; additional studies underway Eight species of waterfowl No No Sample size small; findings not conclusive; elevated selenium in some eggs at high-exposure sites, but high- exposure sites not well represented in brood counts; small populations and difficulty finding nests preclude further studies without the use of sophisticated radiotelemetry Longnose sucker Uncertain Uncertain Columbia spotted frog Uncertain Uncertain Indications that selenium may be causing deformities in fry/tadpoles; studies far from definitive due to methodological problems; additional studies underway  However, studies conducted to date do suggest that some negative effects are occurring on a more localized level (Table 1). The extent and significance of negative effects in lentic areas with high levels of selenium, i.e., whether or not there are population-level impacts, remains to be determined.  The results of effects studies conducted in 2005 will be evaluated in terms of the significance and extent of any effects / impacts. Water selenium concentrations (early warning) will be used to project future scenarios. The possibility of management actions, if necessary, will be assessed accordingly.  REFERENCES  Elk Valley Mines Environmental Management Committee (EVMEMC). 2004. Selenium status report 2003 – Elk River Valley, BC.  Elk Valley Selenium Task Force (EVSTF), 2005. Selenium status report 2004 – Elk River Valley, BC.  Harding LE, Graham M, Paton D. 2005. Accumulation of selenium and lack of severe effects on productivity of American dippers (Cinclus mexicanus) and spotted sandpipers (Actitis macularia). Archives of Environmental Contamination and Toxicology 48: 414-423.  Minnow Environmental. 2003. Selenium study of lentic areas in the Elk Valley. Report prepared for the Elk Valley Mines Environmental Management Committee.  Minnow Environmental. 2004a. Selenium uptake in biota inhabiting lentic and lotic areas of the Elk River Watershed. Report prepared for the Elk Valley Mines Environmental Management Committee.  Minnow Environmental. 2004b. Assessment of selenium effects on long nose suckers and Columbia spotted frogs in selected lentic areas of the Elk River Valley. Draft report prepared for the Elk Valley Mines Environmental Management Committee.  Orr P, Guiguer K, Russel C. 2004. Investigation of selenium uptake pathways in lentic and lotic aquatic habitats using stable isotope analysis. In: Burridge LE, Haya K, Niimi AJ, Proceedings of the 31st Annual Aquatic Toxicity Workshop. October 24 to 27, 2004, Charlottetown, PEI. Canadian Technical Report of Fisheries and Aquatic Sciences 2562.  SciWrite. 2004a. Effects of selenium on red-winged blackbirds in the Elk Valley, 2004. Draft report prepared for the Elk Valley Mines Environmental Management Committee.  SciWrite. 2004b. Uptake of selenium and productivity in waterfowl in the Elk River Valley, British Columbia. Draft report prepared for the Elk Valley Mines Environmental Management Committee.  Simmons DBC, Wallschläger D. 2005. A critical review of the biogeochemistry and ecotoxicology of selenium in lotic and lentic environments. Environmental Toxicology and Chemistry 24: 1331-1343.  Vasterling RP. 2003. Selenium contamination effects on avian reproductive success and population dynamics in phosphate-mining regions of southeastern Idaho. M.Sc. Thesis, University of Idaho, Moscow, ID. 


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