Linda E. Kimpe

Bioaccumulation of the pharmaceutical 17α-ethinylestradiol in shorthead redhorse suckers (Moxostoma macrolepidotum) from the St. Clair River, Canada.

17alpha-ethynylestradiol (EE2), a synthetic estrogen prescribed as a contraceptive, was measured in Shorthead Redhorse Suckers (ShRHSs) (Moxostoma macrolepidotum) collected near a wastewater treatment plant (WWTP) in the St. Clair River (Ontario, Canada). We detected EE2 in 50% of the fish samples caught near the WWTP (Stag Island), which averaged 1.6+/-0.6ng/g (wet weight) in males and 1.43+/-0.96ng/g in females. No EE2 was detected in the samples from the reference site (Port Lambton) which was 26km further downstream of the Stag Island site. Only males from Stag Island had VTG induction, suggesting the Corunna WWTP effluent as a likely source of environmental estrogen. EE2 concentrations were correlated with total body lipid content (R(2)=0.512, p<0.01, n=10). Lipid normalized EE2 concentrations were correlated with delta(15)N (R(2)=0.436, p<0.05, n=10), suggesting higher EE2 exposures in carnivores. Our data support the hypothesis of EE2 bioaccumulation in wild fish.

Dissolved Organic Carbon Thresholds Affect Mercury Bioaccumulation in Arctic Lakes

Dissolved organic carbon (DOC) is known to affect the Hg cycle in aquatic environments due to its overriding influence on complexation, photochemical, and microbial processes, but its role as a mediating factor in the bioaccumulation of Hg in aquatic biota has remained enigmatic. Here, we examined 26 tundra lakes in Canadas western Arctic that span a large gradient of DOC concentrations to show that total Hg (HgT) and methyl mercury (MeHg) accumulation by aquatic invertebrates is defined by a threshold response to Hg-DOC binding. Our results showed that DOC promotes HgT and MeHg bioaccumulation in tundra lakes having low DOC (<8.6 - 8.8 mg C L(-1); DOC threshold concentration, TC) whereas DOC inhibits HgT and MeHg bioaccumulation in lakes having high DOC (>DOC TC), consistent with bioaccumulation results in a companion paper (this issue) using a microbial bioreporter. Chemical equilibrium modeling showed that Hg bioaccumulation factors were elevated when Hg was associated mainly to fulvic acids, but became dramatically reduced when DOC was >8.5 mg C L(-1), at which point Hg was associated primarily with strong binding sites on larger, less bioaccessible humic acids. This study demonstrates that the biological uptake of Hg in lakes is determined by binding thresholds on DOC, a water quality variable predicted to change markedly with future environmental change.

Spatial and Temporal Assessment of Mercury and Organic Matter in Thermokarst Affected Lakes of the Mackenzie Delta Uplands, NT, Canada

We examined dated sediment cores from 14 thermokarst affected lakes in the Mackenzie Delta uplands, NT, Arctic Canada, using a case-control analysis to determine how retrogressive thaw slump development from degrading permafrost affected the delivery of mercury (Hg) and organic carbon (OC) to lakes. We show that sediments from the lakes with retrogressive thaw slump development on their shorelines (slump-affected lakes) had higher sedimentation rates and lower total Hg (THg), methyl mercury (MeHg), and lower organic carbon concentrations compared to lakes where thaw slumps were absent (reference lakes). There was no difference in focus-corrected Hg flux to sediments between reference lakes and slump-affected lakes, indicating that the lower sediment Hg concentration in slump-affected lakes was due to dilution by rapid inorganic sedimentation in the slump-affected lakes. Sedimentation rates were inversely correlated with THg concentrations in sediments among the 14 lakes considered, and explained 68% of the variance in THg concentration in surface sediment, further supporting the dilution hypothesis. We observed higher S2 (algal-derived carbon) and particulate organic carbon (POC) concentrations in sediment profiles from reference lakes than in slump lakes, likely because of dilution by inorganic siliciclastic matter in cores from slump-affected lakes. We conclude that retrogressive thaw slump development increases inorganic sedimentation in lakes, and decreases concentrations of organic carbon and associated Hg and MeHg in sediments.

The development of an optimized sample preparation for trace level detection of 17α-ethinylestradiol and estrone in whole fish tissue.

The purpose of this study was to develop an optimized method for the extraction and determination of 17α-ethinylestradiol (EE2) and estrone (E1) in whole fish tissues at ng/g levels. The optimized procedure for sample preparation includes extraction of tissue by accelerated solvent extraction (ASE-200), lipid removal by gel permeation chromatography (GPC), and a cleanup step by acetonitrile precipitation followed by a hexane wash. Analysis was performed by gas chromatography/mass spectrometry (GC/MS) in negative chemical ionization (NCI) mode after samples were derivatized with pentafluorobenzoyl chloride (PFBCl). The method was developed using high lipid content wild fish that were exposed to the tested analytes. The whole procedure recoveries ranged from 74.5 to 93.7% with relative standard deviation (RSD) of 2.3-6.2% for EE2 and 64.8 to 91.6% with RSD of 9.46-0.18% for E1. The method detection limits were 0.67 ng/g for EE2 and 0.68 ng/g for E1 dry weight. The method was applied to determine EE2 levels in male goldfish (Carrasius auratus) after a 72 h dietary exposure. All samples contained EE2 averaging 1.7ng/g (±0.29 standard deviation, n=5). This is the first optimized protocol for EE2 extraction from whole fish tissue at environmentally relevant concentrations. Due to high sensitivity and recovery, the developed method will improve our knowledge about the environmental fate and uptake of synthetic steroidal estrogens in fish populations.

Multi-trophic level response to extreme metal contamination from gold mining in a subarctic lake

Giant Mine, located in the city of Yellowknife (Northwest Territories, Canada), is a dramatic example of subarctic legacy contamination from mining activities, with remediation costs projected to exceed

Is there widespread metal contamination from in-situ bitumen extraction at Cold Lake, Alberta heavy oil field?

1 billion. Operational between 1948 and 2004, gold extraction at Giant Mine released large quantities of arsenic and metals from the roasting of arsenopyrite ore. We examined the long-term ecological effects of roaster emissions on Pocket Lake, a small lake at the edge of the Giant Mine lease boundary, using a spectrum of palaeoenvironmental approaches. A dated sedimentary profile tracked striking increases (approx. 1700%) in arsenic concentrations coeval with the initiation of Giant Mine operations. Large increases in mercury, antimony and lead also occurred. Synchronous changes in biological indicator assemblages from multiple aquatic trophic levels, in both benthic and pelagic habitats, indicate dramatic ecological responses to extreme metal(loid) contamination. At the peak of contamination, all Cladocera, a keystone group of primary consumers, as well as all planktonic diatoms, were functionally lost from the sediment record. No biological recovery has been inferred, despite the fact that the bulk of metal(loid) emissions occurred more than 50 years ago, and the cessation of all ore-roasting activities in Yellowknife in 1999.

Elevated contaminants contrasted with potential benefits of ω-3 fatty acids in wild food consumers of two remote first nations communities in northern Ontario, Canada.

The extraction of oil sands by in-situ methods in Alberta has expanded dramatically in the past two decades and will soon overtake surface mining as the dominant bitumen production process in the province. While concerns regarding regional metal emissions from oil sand mining and bitumen upgrading have arisen, there is a lack of information on emissions from the in-situ industry alone. Here we show using lake sediment records and regionally-distributed soil samples that in the absence of bitumen upgrading and surface mining, there has been no significant metal (As, Cd, Cu, Hg, Ni, Pb, V) enrichment from the Cold Lake in-situ oil field. Sediment records demonstrate post-industrial Cd, Hg and Pb enrichment beginning in the early Twentieth Century, which has leveled off or declined since the onset of commercial in-situ bitumen production at Cold Lake in 1985.

Exploratory Hydrocarbon Drilling Impacts to Arctic Lake Ecosystems

Indigenous communities in Boreal environments rely on locally-harvested wild foods for sustenance. These foods provide many nutritional benefits including higher levels of polyunsaturated fatty acids (PUFAs; such as ω-3) than what is commonly found in store-bought foods. However, wild foods can be a route of exposure to dietary mercury and persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs). Here, we show a strong association between the frequency of wild food consumption in adults (N = 72) from two remote First Nations communities of Northern Ontario and environmental contaminants in blood (POPs) and hair (mercury). We observed that POPs and mercury were on average 3.5 times higher among those consuming wild foods more often, with many frequent wild food consumers exceeding Canadian and international health guidelines for PCB and mercury exposures. Contaminants in locally-harvested fish and game from these communities were sufficiently high that many participants exceeded the monthly consumption limits for methylmercury and PCBs. Those consuming more wild foods also had higher proportions of potentially beneficial ω-3 fatty acids including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These results show that the benefits of traditional dietary choices in Boreal regions of Canada must be weighed against the inherent risks of contaminant exposure from these foods.

Tracking the History and Ecological Changes of Rising Double-Crested Cormorant Populations Using Pond Sediments from Islands in Eastern Lake Ontario

Recent attention regarding the impacts of oil and gas development and exploitation has focused on the unintentional release of hydrocarbons into the environment, whilst the potential negative effects of other possible avenues of environmental contamination are less well documented. In the hydrocarbon-rich and ecologically sensitive Mackenzie Delta region (NT, Canada), saline wastes associated with hydrocarbon exploration have typically been disposed of in drilling sumps (i.e., large pits excavated into the permafrost) that were believed to be a permanent containment solution. However, failure of permafrost as a waste containment medium may cause impacts to lakes in this sensitive environment. Here, we examine the effects of degrading drilling sumps on water quality by combining paleolimnological approaches with the analysis of an extensive present-day water chemistry dataset. This dataset includes lakes believed to have been impacted by saline drilling fluids leaching from drilling sumps, lakes with no visible disturbances, and lakes impacted by significant, naturally occurring permafrost thaw in the form of retrogressive thaw slumps. We show that lakes impacted by compromised drilling sumps have significantly elevated lakewater conductivity levels compared to control sites. Chloride levels are particularly elevated in sump-impacted lakes relative to all other lakes included in the survey. Paleolimnological analyses showed that invertebrate assemblages appear to have responded to the leaching of drilling wastes by a discernible increase in a taxon known to be tolerant of elevated conductivity coincident with the timing of sump construction. This suggests construction and abandonment techniques at, or soon after, sump establishment may result in impacts to downstream aquatic ecosystems. With hydrocarbon development in the north predicted to expand in the coming decades, the use of sumps must be examined in light of the threat of accelerated permafrost thaw, and the potential for these industrial wastes to impact sensitive Arctic ecosystems.

Assessing the contribution of combustion-derived contaminants to a remote subarctic environment from traffic on the Tibbitt to Contwoyto winter road (Northwest Territories, Canada).

In the Laurentian Great Lakes region, the double-crested cormorant (Phalacrocorax auritus) has seen a thousand-fold population increase in recent decades. These large colonies of birds now often conflict with socioeconomic interests, particularly due to perceived competition with fisheries and the destruction of terrestrial vegetation in nesting habitats. Here we use dated sediment cores from ponds on islands in eastern Lake Ontario that receive waste inputs from dense colonies of cormorants and ring-billed gulls (Larus delawarensis) to chronicle the population rise of these species and assess their long-term ecological impacts. Modern water chemistry sampling from these sites reveals drastically elevated nutrient and major ion concentrations compared to reference ponds not influenced by waterbirds. Geochemical tracers in dated sediment cores, particularly δ15N and chlorophyll-a concentrations, track waterbird influences over time. Fossil diatom assemblages were dominated by species tolerant of hyper-eutrophic and polluted systems, which is in marked contrast to assemblages in reference sites. In addition to establishing long-term ecological impacts, this multi-proxy paleoecological approach can be used to determine whether islands of concern have been long-term nesting sites or were only recently colonized by cormorant or ring-billed gull populations across the Great Lakes, facilitating informed management decisions about controversial culling programs.