Long-range transport of legacy organic pollutants affects alpine fish eaten by ospreys in western Canada.

Persistent organic pollutants (POPs) contaminate pristine, alpine environments through long-range transport in the atmosphere and glacier trapping. To study variation in POPs levels in western Canada, we measured levels in the prey (fish) of osprey (Pandion haliaetus) during 1999-2004, and compared those to levels in eggs and chicks. Values in fish muscle (representing human consumption) correlated with whole carcasses (wildlife consumption) for all POPs, except toxaphene, allowing us to pool data. Biomagnification factors for osprey eggs were much higher than published values from Oregon, reflecting differences in local diet. We factored baseline-corrected food chain variation by using amino acid-specific analysis of osprey eggs, illustrating how top predators (ospreys) can indicate both ecosystem-wide baselines and contamination. Given that our biomagnification factors were so different from those for the same species from a nearby site, we argue that trophic magnification factors derived from baseline-corrected δ15N are likely a more accurate method for estimating contamination. Dichlorodiphenyltrichloroethane (ΣDDT) concentrations were greatest in rainbow trout from a small lake at 1800 m, and those levels exceeded wildlife and human health guidelines. Indeed, once sites with known agricultural inputs were eliminated, elevation, percent lipids and baseline-corrected δ15N (from amino acid specific isotope values) best predicted ΣDDT. Baseline-corrected, but not bulk, δ15N was the main predictor of polychlorinated biphenyls (ΣPCB). Total toxaphene was consistently the major contaminant after ΣPCB and ΣDDT in osprey eggs, and was present in many fish samples. We concluded that toxaphene arrived from long range deposition due to high proportions of Parlar 40-50 congeners. The only exception was Paul Lake, where toxaphene was used as a piscicide, with a high concentrations of the Hex-Sed and Hep-Sed congeners at that site. We conclude that long-range transport and trophic position, not melting glaciers, were important determinants of some legacy POPs in fish and wildlife in alpine Canada.

Recent progress on our understanding of the biological effects of mercury in fish and wildlife in the Canadian Arctic.

This review summarizes our current state of knowledge regarding the potential biological effects of mercury (Hg) exposure on fish and wildlife in the Canadian Arctic. Although Hg in most freshwater fish from northern Canada was not sufficiently elevated to be of concern, a few lakes in the Northwest Territories and Nunavut contained fish of certain species (e.g. northern pike, Arctic char) whose muscle Hg concentrations exceeded an estimated threshold range (0.5-1.0 µg g(-1) wet weight) within which adverse biological effects begin to occur. Marine fish species generally had substantially lower Hg concentrations than freshwater fish; but the Greenland shark, a long-lived predatory species, had mean muscle Hg concentrations exceeding the threshold range for possible effects on health or reproduction. An examination of recent egg Hg concentrations for marine birds from the Canadian Arctic indicated that mean Hg concentration in ivory gulls from Seymour Island fell within the threshold range associated with adverse effects on reproduction in birds. Mercury concentrations in brain tissue of beluga whales and polar bears were generally lower than levels associated with neurotoxicity in mammals, but were sometimes high enough to cause subtle neurochemical changes that can precede overt neurotoxicity. Harbour seals from western Hudson Bay had elevated mean liver Hg concentrations along with comparatively high muscle Hg concentrations indicating potential health effects from methylmercury (MeHg) exposure on this subpopulation. Because current information is generally insufficient to determine with confidence whether Hg exposure is impacting the health of specific fish or wildlife populations in the Canadian Arctic, biological effects studies should comprise a major focus of future Hg research in the Canadian Arctic. Additionally, studies on cellular interactions between Hg and selenium (Se) are required to better account for potential protective effects of Se on Hg toxicity, especially in large predatory Arctic fish, birds, and mammals.

Factors influencing legacy pollutant accumulation in alpine osprey: biology, topography, or melting glaciers?

Persistent organic pollutants (POPs) can be transported long distances and deposited into alpine environments via cold trapping and snow scavenging processes. Here we examined biotic and abiotic factors determining contaminant variability of wildlife in alpine ecosystems. We measured POPs in eggs and plasma of an apex predator, the osprey (Pandion haliaetus) breeding in 15 mountainous watersheds across a broad latitudinal, longitudinal and altitudinal range in western Canada. After accounting for proximate biotic factors such as trophic level (δ(15)N) and carbon source (δ(13)C), variability in contaminant concentrations, including ΣDDT (sum of trichlorodiphenylethane-related compounds), toxaphene, hexachlorobenzene (HCB), total chlordane, and ΣPCBs (polychlorinated biphenyls) in osprey tissues was explained by interactions among relative size of watersheds, water bodies, elevation, and glacial input. ΣDDT in nestling plasma, for example, decreased with lake elevation, probably as a result of local past inputs from agricultural or public health usage at lower altitude sites. In contrast, toxaphene, never used as an insecticide in western Canada, increased with elevation and year-round snow and ice cover in both plasma and eggs, indicating long-range atmospheric sources as dominant for toxaphene. Lower chlorinated PCBs in plasma tended to decrease with elevation and ice cover consistent with published data and model outcomes. Temporal trends of POPs in osprey eggs are coincident with some modeled predictions of release from melting glaciers due to climate change. Currently we suggest that contaminants largely are released through annual snowpack melt and deposited in large lower elevation lakes, or some smaller lakes with poor drainage. Our study highlights the importance of understanding how biological processes integrate physical when studying the environmental chemistry of wildlife.

Flame retardants in eggs of four gull species (Laridae) from breeding sites spanning Atlantic to Pacific Canada.

To compare legacy and emerging flame retardant (FR) contamination in Canadian marine and freshwater ecosystems, eggs of four gull species (Laridae) were collected from 26 colonies spanning Pacific to Atlantic Canada, including in the Great Lakes basin. Fourteen polybrominated diphenyl ether (PBDE) congeners and 20 non-PBDE FRs were analyzed, but BDE-47, -99, -100, -153, -154 and -209, hexabromocyclododecane (HBCD) and Dechlorane Plus (DP) syn- and anti-isomers were common, and where concentrations of ∑PBDEs (37-610 ng/g wet weight, ww) â‰« HBCD (0.5-12 ng/g ww) > ∑DP (not quantifiable-5.5 ng/g ww). All other FRs were generally not detectable. Stable nitrogen and carbon isotopes used as dietary tracers provided insights into the diet choice influences on the exposure sources and contamination patterns (e.g., PBDE congener compositions) for individual gulls from the same colony. Eggs from gulls breeding near metropolitan regions of higher human densities showed greater PBDE burdens than from other ecosystems.

Differential exposure of alpine ospreys to mercury: melting glaciers, hydrology or deposition patterns?

Mercury (Hg) is a global contaminant impacting even remote environments. In alpine watersheds, glacial meltwater is a source of Hg, which accumulated in glaciers during the 1960-1980 cooling cycle. The considerable variation observed for Hg exposure of alpine animals in proximal watersheds could result from differences among those watersheds in Hg loading from glacial meltwater. Alternatively, variation may be the result of hydrology, atmospheric Hg deposition patterns, or food web characteristics. To examine those possibilities, we measured Hg in ospreys (Pandion haliaetus), apex predators in 15 watersheds in western Canada. Mercury levels in feathers of nestlings increased with increasing modeled atmospheric deposition rates and decreased with lake size. In eggs mercury decreased with δ(13)C, an indicator of food web structure, and with pH and elevation. Thus, Hg levels in chicks were strongly associated with local patterns relevant when the chicks were growing (e.g. the period post-snow melt: Hg deposition, lake size) while Hg levels in eggs were weakly associated with local patterns relevant during the snow melt (elevation, δ(13)C), with the remainder of the Hg variation in eggs determined by other factors such as possible Hg accumulation by the adult elsewhere. Modeled atmospheric deposition from prevailing upwind locations including Asia, followed by runoff into small lakes, were related to Hg patterns in osprey, with little apparent role for recent melting of glaciers. Our study highlights the importance of physical patterns to the environmental chemistry of top predators.

Selenium accumulation and reproduction in birds breeding downstream of a uranium mill in northern Saskatchewan, Canada.

Selenium (Se) concentrations in aquatic invertebrates and bird eggs collected along the treated effluent receiving environment of the Key Lake uranium mill in northern Saskatchewan were significantly greater than from nearby reference areas, and in some cases (e.g., eggs of common loons--Gavia immer) were higher than commonly used thresholds for adverse reproductive effects in birds (i.e., 5 µg/g dry weight in diet; 12-15 µg/g dry weight in eggs). Mean Se concentrations in tree swallow (Tachycineta bicolor) eggs reached a maximum of 13.3 µg/g dry weight at the point of treated effluent discharge and exhibited a gradient of decreasing Se concentrations with increasing distance from the effluent discharge, probably reflecting both effluent dilution and local site fidelity by nesting swallows. In some cases, high intra-clutch variability in Se concentrations in mallard (Anas platyrhynchos) and tree swallow eggs was observed in high-Se sites, suggesting that a single egg randomly sampled from a nest in an area of higher Se exposure may not be representative of Se concentrations in other eggs from the same nest. Overall, tree swallow reproductive success was similar in both exposed and reference areas.

Perfluoroalkyl carboxylates and sulfonates and precursors in relation to dietary source tracers in the eggs of four species of gulls (Larids) from breeding sites spanning Atlantic to Pacific Canada.

In the present study, we identified and examined the spatial trends, sources and dietary relationships of bioaccumulative perfluorinated sulfonate (PFSA; C(6), C(8), and C(10) chain lengths) and carboxylate (PFCA; C(6) to C(15) chain lengths) contaminants, as well as precursor compounds including several perfluorinated sulfonamides, and fluorotelomer acids and alcohols, in individual eggs (collected in 2008) from four gull species [glaucous-winged (Larus glaucescens), California (Larus californicus), ring-billed (Larus delawarensis) and herring (Larus argentatus) gulls] from 15 marine and freshwater colony sites in provinces across Canada. The pattern of PFSAs was dominated by perfluorooctane sulfonate (PFOS; >89% of ΣPFSA concentration) regardless of egg collection location. The highest ΣPFSA concentrations were found in the eggs collected in the urbanized areas in the Great Lakes and the St. Lawrence River area [Big Chicken Island 308 ng/g ww, Toronto Harbour 486 ng/g ww, and Ile Deslauriers (HG) 299 ng/g ww]. Also, eggs from all freshwater colony sites had higher ΣPFSA concentrations, which were significant (p<0.05) in many cases, compared to the marine sites with the exception of the Sable Island colony in Atlantic Canada off the coast of Nova Scotia. C(6) to C(15) chain length PFCAs were detected in the eggs, although the pattern was variable among the 15 sites, where PFUnA and PFTrA dominated the pattern for most colonies. Like the ΣPFSA, the highest concentrations of ΣPFCA were found in the eggs from Big Chicken Island, Toronto Harbour, Ile Deslauriers (HG), and Sable Island, although not all freshwater sites had higher concentrations compared to marine sites. Dietary tracers [δ(15)N and δ(13)C stable isotopes (SIs)] revealed that PFSA and PFCA exposure is colony dependent. SI signatures suggested that gulls from most marine colony sites were exposed to PFCs via marine prey. The exception was the Mandarte Island colony in Pacific British Columbia, where PFSA and PFCA exposure appeared to be via terrestrial and/or freshwater prey consumption. The same was true for the freshwater sites where egg SIs suggested both aquatic and terrestrial prey consumption as the source for PFC exposure depending on the colony. Both aquatic (marine and freshwater) and terrestrial prey are likely sources of PFC exposure to gulls but exposure scenarios are colony-specific.

Evidence of weak contaminant-related oxidative stress in glaucous gulls (Larus hyperboreus) from the Canadian Arctic.

Environmental contaminants are transported over great distances to Arctic ecosystems, where they can accumulate in wildlife. Whether contaminant concentrations in wildlife are sufficient to produce adverse effects remains poorly understood. Exposure to contaminants elevates oxidative stress with possible fitness consequences. The glaucous gull (Larus hyperboreus), an Arctic top predator, was used as a bioindicator for investigating relationships between contaminant levels (organochlorines and polychlorinated biphenyls [OC/PCB], mercury [Hg], and selenium [Se]) and measures of oxidative stress (glutathione [GSH] metabolism and lipid peroxidation) in Canadian Arctic ecosystems. Contaminant levels were low and associations between contaminant exposure and oxidative stress were weak. Nevertheless, glutathione peroxidase activity rose with increasing hepatic Se concentrations, levels of thiols declined as Hg and OC/PCB levels rose, and at one of the two study sites levels of lipid peroxidation were elevated with increasing levels of hepatic Hg. These results suggest the possibility of a deleterious effect of exposure to contaminants on gull physiology even at low contaminant exposures.

Trace element concentrations in blood of nesting king eiders in the canadian arctic.

The king eider (Somateria spectabilis) is a migratory species of sea duck whose North American population is thought to be declining. We determined levels of cadmium, lead, selenium, and mercury in blood from female king eiders nesting in the central Canadian Arctic from 2001 to 2003. Year-to-year repeatability estimates were calculated from birds sampled in 2 or 3 years. Repeatability coefficients were 0.45, 0.35, 0.58, and 0.25 for cadmium, lead, selenium, and mercury, respectively. The first three were significantly different from zero (p < 0.05), whereas the last approached significance (0.05 < p < 0.1). In 2001 and 2002, we also identified probable wintering locations of a subset of the birds. In both years, cadmium levels were higher and selenium levels were lower in birds inferred to have wintered in the eastern part of their range compared to those that had wintered in the west. There was little evidence that timing of breeding, timing of sampling, or body condition were related to levels of these trace elements, although in 1 of 2 years, lead levels were influenced by body condition and nest initiation date (R(2) = 0.24) and cadmium levels were related to incubation day (partial R(2) = 0.04). Year-to-year repeatability of cadmium and selenium levels among individuals in this population of king eiders was likely influenced by where they wintered.

Is selenium affecting body condition and reproduction in boreal breeding scaup, scoters, and ring-necked ducks?

Elevated levels of selenium (Se) have been detected in wintering and spring-staging lesser scaup. Here, we compared spring scaup Se and mercury (Hg) levels to those of ring-necked ducks and white-winged scoters, species exhibiting increasing and decreasing boreal populations, respectively. Mercury concentrations were low in all three species. Geometric mean (95%CI) liver Se concentrations were 6.2 (5.5-7.0), 4.6 (4.0-5.4), and 32.6 (28.4-37.3)mg/kg dry weight (dw) in scaup, ringnecks and scoters, respectively. Only scoter livers (66%) were above 33 mg/kgdw Se. Scaup and ringneck Se levels were unrelated to breeding status or lipid and protein levels; breeding scoters and females with greater lipid mass had higher Se than non-breeders. Egg and follicle concentrations in scaup and scoters were normal (mean [95%CI]=2.3 [1.9-2.6] and 2.4 [2.1-2.7]mg/kgdw, respectively). Overall, we found no support for a relationship between selenium and boreal scaup and scoter declines, and discuss current Se threshold concentrations.

Levels of polycyclic aromatic hydrocarbons and dibenzothiophenes in wetland sediments and aquatic insects in the oil sands area of northeastern Alberta, Canada.

An immense volume of tailings and tailings water is accumulating in tailings ponds located on mine leases in the oil sands area of Alberta, Canada. Oil sands mining companies have proposed to use tailings- and tailings water-amended lakes and wetlands as part of their mine remediation plans. Polycyclic aromatic hydrocarbons (PAHs) are substances of concern in oil sands tailings and tailings water. In this study, we determined concentrations of PAHs in sediments, insect larvae and adult insects collected in or adjacent to three groups of wetlands: experimental wetlands to which tailings or tailings water had been purposely added, oil sands wetlands that were located on the mine leases but which had not been experimentally manipulated and reference wetlands located near the mine leases. Alkylated PAHs dominated the PAH profile in all types of samples in the three categories of wetlands. Median and maximum PAH concentrations, especially alkylated PAH concentrations, tended to be higher in sediments and insect larvae in experimental wetlands than in the other types of wetlands. Such was not the case for adult insects, which contained higher than expected levels of PAHs in the three types of ponds. Overlap in PAH concentrations in larvae among pond types suggests that any increase in PAH levels resulting from the addition of tailings and tailings water to wetlands would be modest. Biota-sediment accumulation factors were higher for alkylated PAHs than for their parent counterparts and were lower in experimental wetlands than in oil sands and reference wetlands. Research is needed to examine factors that affect the bioavailability of PAHs in oil sands tailings- or tailings water-amended wetlands.

Survival rates and blood metal concentrations in two species of free-ranging North American sea ducks.

Populations of several species of North American sea ducks have declined in the past few decades. Exposure to environmental contaminants, particularly metals, has been proposed as one of many possible factors contributing to these declines. Population dynamics are influenced by survival rates and breeding effort. In the present study, we examined the relationships between blood metal concentrations (Cd, Pb, Se, and Hg) and apparent annual survival and recapture probabilities (the latter as a surrogate for breeding effort) in adult females of two sea duck species, the king eider (Somateria spectabilis) and the white-winged scoter (Melanitta fusca), both of which have experienced declines in continental population during in recent years. No support was found for the hypothesis that exposure of white-winged scoters to these metals or of king eiders to Cd, Se, and Pb adversely affected probabilities of apparent annual survival. We detected a weak negative relationship (beta = -0.833) between Hg and annual survival of king eiders, but the 90% confidence interval of the slope estimate overlapped zero (-2.439 to +0.672). Recapture probabilities were unrelated to concentrations of Cd, Se, and Pb in either species. Evidence indicated that Hg concentrations affected recapture probability in white-winged scoters (beta = -194.77; 90% confidence interval, -203.770 to -185.778). Mercury levels were low in both species, and blood samples may not adequately represent long-term exposure to Hg. Therefore, conclusions regarding Hg effects on these birds should be considered with caution.

Speciation of selenium in stream insects using X-ray absorption spectroscopy.

Selenium contamination in the environment is a widespread problem affecting insects and other wildlife. Insects occupy a critical middle link and aid in trophic transfer of selenium in many terrestrial and freshwater food chains, but the mechanisms of selenium uptake through the food chain are poorly understood. In particular, biotransformation of selenium by insects into different chemical forms will greatly influence how toxic or benign the selenium is to that organism or to its predators. We have used X-ray absorption spectroscopy (XAS) to identify the chemical form of selenium in insects inhabiting selenium contaminated streams near Hinton, Alberta (Canada). Selenium K near-edge spectra indicate a variability of selenium speciation among the insects that included mayflies (Ephemeroptera), stoneflies (Plecoptera), caddisflies (Trichoptera), and craneflies (Diptera). Higher percentages of inorganic selenium were observed in primary consumers, detritivores, and filter feeders than in predatory insects. Among the organic forms of selenium, organic selenides constituted a major fraction in most organisms. A species modeled as trimethylselenonium was observed during the pupal stage of caddisflies. These results provide insights into how the insects cope with their toxic cargo, including how the selenium is biotransformed into less toxic forms and how it can be eliminated from the insects. More broadly, this study demonstrates the strengths of XAS to probe the effects of heavy elements at trace levels in insects from the field.

The American dipper as a bioindicator of selenium contamination in a coal mine-affected stream in west-central Alberta, Canada.

Elevated levels of selenium have been found in water and aquatic biota downstream from two open-pit coal mines in the Rocky Mountain foothills of Alberta. Birds are particularly sensitive to excessive dietary selenium. However, there is relatively little information on selenium accumulation in birds' eggs on fast-flowing mountain streams. We determined levels of selenium in water samples, caddisfly larvae and eggs of American dippers (Cinclus mexicanus) nesting on the Gregg River, downstream from the mines, and on reference streams in the same general vicinity. Selenium levels (mean, 95% confidence limits) in water samples and caddisflies collected from sites near dipper nests on the Gregg River (water: 4.26, 1.90-9.56 microg L(-1); caddisflies: 8.43, 7.51-9.46 microg g dry wt(-1)) were greater than those collected from sites near nests on reference rivers (water: 0.38, 0.21-0.71 microg L(-1); caddisflies: 4.65, 4.35-4.97 microg g dry wt(-1)). The mean (+/- 1SE) selenium level in dipper eggs from the Gregg River (6.3 +/- 0.2 microg g(-1) dry wt) was significantly higher than it was in eggs from reference streams (4.9 +/- 0.2 microg g(-1) dry wt). Concentrations of selenium in eggs were significantly correlated with those in water samples (r = 0.45). The maximum selenium level in eggs from the Gregg River (9.0 microg g(-1)) may have been high enough to warrant concern from an ecotoxicological perspective. The American dipper can serve as a useful bioindicator of selenium contamination in mountainous, lotic ecosystems.

Selenium and other trace elements in aquatic insects in coal mine-affected streams in the Rocky Mountains of Alberta, Canada.

We determined levels of Se, As, Cd, Pb, and Zn in aquatic insects at coal mine-impacted and reference sites in streams in the Rocky Mountain foothills of west central Alberta from 2001-2003. Selenium levels were greater at coal mine-impacted sites than at reference sites in caddisflies but not in mayflies or stoneflies. Arsenic levels were greater at coal mine-impacted sites than at reference sites in caddisflies and stoneflies but not in mayflies. Zn levels were higher at coal mine-impacted sites than at reference sites in all three groups of insects. At coal mine-impacted sites, Se levels in mayflies and caddisflies were greater than those in stoneflies while at reference sites mayflies contained greater concentrations of Se than either caddisflies or stoneflies. Arsenic levels in mayflies were greater than those in caddisflies at reference and coal mine-impacted sites and were greater than those in stoneflies at reference sites. At both types of sites Cd differed amongst insect taxa in the order of mayflies > caddisflies > stoneflies. The same was true of Zn at coal mine-affected sites. At reference sites, stoneflies had greater concentrations of Zn than both mayflies and caddisflies. At both types of sites, Pb levels were greater in mayflies and caddisflies than they were in stoneflies. Of the five trace elements considered in this study, only Se was sufficiently elevated in aquatic invertebrates to be of potential concern for consumers such as fish and aquatic birds. Such was the case at both coal mine-impacted and reference sites.

An assessment of the toxicological significance of anthropogenic contaminants in Canadian arctic wildlife.

Anthropogenic contaminants have been a concern in the Canadian arctic for over 30 years due to relatively high concentrations of bioaccumulating and biomagnifying organochlorine contaminants (OCs) and toxic metals found in some arctic biota and humans. However, few studies have addressed the potential effects of these contaminants in Canadian arctic wildlife. Prior to 1997, biological effects data were minimal and insufficient at any level of biological organization. The present review summarizes recent studies on biological effects related to contaminant exposure, and compares new tissue concentration data to threshold effects levels. Weak relationships between cadmium, mercury and selenium burdens and health biomarkers in common eider ducks (Somateria mollissima borealis) in Nunavut were found but it was concluded that metals were not influencing the health of these birds. Black guillemots (Cepphus grylle) examined near PCB-contaminated Saglek Bay, Labrador, had enlarged livers, elevated EROD and liver lipid levels and reduced retinol (vitamin A) and retinyl palmitate levels, which correlated to PCB levels in the birds. Circulating levels of thyroid hormones in polar bears (Ursus maritimus) were correlated to PCB and HO-PCB plasma concentrations, but the impact at the population level is unknown. High PCB and organochlorine pesticide concentrations were found to be strongly associated with impaired humoral and cell-mediated immune responses in polar bears, implying an increased infection risk that could impact the population. In beluga whale (Delphinapterus leucas), cytochromes P450 (phase I) and conjugating (phase II) enzymes have been extensively profiled (immunochemically and catalytically) in liver, demonstrating the importance of contaminants in relation to enzyme induction, metabolism and potential contaminant bioactivation and fate. Concentrations of OCs and metals in arctic terrestrial wildlife, fish and seabirds are generally below effects thresholds, with the possible exception of PCBs in burbot (Lota lota) in some Yukon lakes, Greenland shark (Somniosus microcephalus), glaucous and great black-backed gulls (Larus hyperboreus and L. marinus), and TEQs of dioxin-like chemicals in seabird eggs. PCB and DDT concentrations in several arctic marine mammal species exceed effects thresholds, although evidence of stress in these populations is lacking. There is little evidence that contaminants are having widespread effects on the health of Canadian arctic organisms, with the possible exception of polar bears. However, further research and better understanding of organohalogen exposure in arctic biota is needed considering factors such as tissue levels that exceed effects thresholds, exposure to "new" organohalogen contaminants of concern, contaminated regions, and climate change.

Concentrations of cadmium, mercury and selenium in common eider ducks in the eastern Canadian arctic: influence of reproductive stage.

Concentrations and total organ content of mercury, selenium and cadmium, as well as liver, kidney and body mass were determined in female common eiders from 1997 to 2000 at the East Bay Migratory Bird Sanctuary in the eastern Canadian arctic. In 1997 and 1999, female eiders were collected during the pre-nesting period when they eat copious amounts of food and gain substantial weight in preparation for the rigours of nesting. In 1998 and 1999, female eiders were collected during the mid to late stages of the nesting period when they eat very little, if at all, and, as a consequence undergo dramatic weight loss. Total body mass, liver mass and kidney mass were highest in pre-nesting birds, especially in 1997. They were significantly lower in nesting birds collected in 1998 and 2000. In contrast, mercury and cadmium concentrations were lowest in pre-nesting birds collected in 1997 and 1999 and increased to significantly higher concentrations in nesting birds collected in 1998 and 2000. In contrast to these results, the total contents of mercury in liver and cadmium in kidney did not change significantly over the 4-year period. Hepatic selenium concentrations were relatively stable over the 4-year study period while changes in the total content of selenium in the liver paralleled changes in liver mass and body mass. The results suggest that mercury and cadmium concentrations in female common eiders change in response to normal changes in body and organ mass that occur during the reproductive period. Thus, it may be important to consider body condition or reproductive stage when using common eiders (and perhaps other species of sea ducks) in biomonitoring studies or when interpreting concentrations of metals in tissues in terms of the risk they pose to these ducks.

Spatial and temporal trends of contaminants in terrestrial biota from the Canadian Arctic.

Contaminants in the Canadian Arctic have been studied over the last twelve years under the guidance of the Northern Contaminants Program. This paper summarizes results from that program from 1998 to 2003 with respect to terrestrial animals in the Canadian Arctic. The arctic terrestrial environment has few significant contaminant issues, particularly when compared with freshwater and marine environments. Both current and historical industrial activities in the north may have a continuing effect on biota in the immediate area, but effects tend to be localized. An investigation of arctic ground squirrels at a site in the Northwest Territories that had historically received applications of DDT concluded that DDT in arctic ground squirrels livers was the result of contamination and that this is an indication of the continuing effect of a local point source of DDT. Arsenic concentrations were higher in berries collected from areas around gold mines in the Northwest Territories than from control sites, suggesting that gold mining may significantly affect arsenic levels in berries in the Yellowknives Dene traditional territory. Although moose and caribou from the Canadian Arctic generally carry relatively low contaminant burdens, Yukon moose had high renal selenium concentrations, and moose and some woodland caribou from the same area had high renal cadmium levels, which may put some animals at risk of toxicological effects. Low hepatic copper levels in some caribou herds may indicate a shortage of copper for metabolic demands, particularly for females. Similarities in patterns of temporal fluctuations in renal element concentrations for moose and caribou suggest that environmental factors may be a major cause of fluctuations in renal concentrations of some elements. Concentrations of persistent organochlorines and metals in beaver and muskrat from the Northwest Territories, and carnivores from across the Canadian Arctic were very low and considered normal for terrestrial wildlife. Two new classes of persistent fluorinated contaminants, perfluorooctane sulfonate (PFOS) and perfluoroalkyl carboxylates (PFCAs) were found in arctic carnivores and were most abundant in arctic fox and least abundant in mink. Although trace element concentrations in king and common eider ducks were low and not of toxicological concern, the number of nematode parasites in common eiders was positively correlated with total and organic mercury concentrations. Future research should focus on cadmium in moose and caribou, mercury in caribou, and emerging contaminants, with an effort to sample moose and caribou annually where possible to explore the role of naturally occurring cycles in apparent temporal trends.

Impact of oil-sands based wetlands on the growth of mallard (Anas platyrhynchos) ducklings.

Identifying the potential effects of industrially formed wetlands on waterfowl populations is important for assessing the suitability of such wetlands in industrial reclamation strategies. Mallard ducklings were held in situ on two industrially formed wetlands and one reference wetland in northern Alberta, Canada. Duckling mass and skeletal size were measured at regular intervals over 33 d, and blood was collected to investigate the analysis of plasma metabolites (triglyceride and glycerol) as an indicator of physiological condition. In repeated-measures analysis of variance (ANOVA), multivariate ANOVA, and subsequent multiple-comparisons tests, body mass and skeletal size were significantly lower in ducklings maintained on the industrial wetland after 2, 5, 9, and 13 d of exposure. In this situation, plasma metabolite analysis did not provide additional information on mass-independent condition. We conclude that if the observed differences in growth and size translate into a decreased survival of juvenile waterfowl inhabiting these wetlands, then populations of these birds in the area could be negatively affected. We emphasize the importance of field-based ecological research in toxicological studies of wildlife.