Mary Simon

Organochlorine contaminants in arctic marine food chains: accumulation of specific polychlorinated biphenyls and chlordane-related compounds

Polychlorinated biphenyl congeners (S-PCB) and chlordane-related compounds (S-CHLOR) as well as DDT, hexachlorocyclohexane, toxaphene, and chlorobenzenes were determined in pooled arctic cod (Boreogadus saida) muscle and polar bear (Ursus maritimus) fat and in the blubber and liver of 59 ringed seals (Phoca hispida) from the east-central Canadian Arctic. S-PCB concentrations ranged from 0.0037 mg/kg (wet wt) in cod muscle to 0.68 mg/kg in male seal blubber and 4.50 mg/kg in bear fat. Tri- and tetrachloro PCB homologues were the dominant PCBs in fish, while pentachloro/hexachloro and hexachloro/heptachloro congeners predominated in ringed seal blubber and polar bear fat, respectively. Chlordane compounds detected in seal blubber were oxychlordane, cis- and trans-nonachlor, and cis-chlordane as well as nine minor components of technical chlordane, including nonachlor-III (a nonachlor isomer). Toxaphene and HCH isomers were the major organochlorines in cod muscle with mean concentrations of 0.018 and 0.010 mg/kg, respectively. S-CHLOR/S-PCB ratios ranged from 0.6 in fish muscle and bear fat to 0.7-0.9 in seal blubber, much higher than observed in more southerly marine environments, suggesting a proportionally greater input of chlordane into the Arctic.

Organochlorine contaminants in arctic marine food chains: identification, geographical distribution and temporal trends in polar bears.

Contamination of Canadian arctic and subarctic marine ecosystems by organochlorine (OC) compounds was measured by analysis of polar bear (Ursus maritimus) tissues collected from 12 zones between 1982 and 1984. PCB congeners (S-PCB), chlordanes, DDT and metabolites, chlorobenzenes (S-CBz), hexachlorocyclohexane isomers (S-HC-H), and dieldrin were identified by high-resolution gas chromatography-mass spectrometry. Nonachlor-III, a nonachlor isomer in technical chlordane, was positively identified for the first time as an environmental contaminant. S-PCB and S-CHLOR accounted for >80% of the total organochlorines in adipose tissue. Six PCB congeners constituted approximately 93% of S-PCB in polar bears. Levels of most OCs were lowest in the high Arctic, intermediate in Baffin Bay, and highest in Hudson Bay. Levels of ..cap alpha..-HCH were evaluated in zones influenced by surface runoff. Levels of S-CHLOR were four times higher and levels of the other OCs were two times higher in adipose tissue of bears from Hudson Bay and Baffin Bay in 1984 than in adipose tissue archived since 1969 from these areas; levels of S-DDT did not change.

Organochlorine chemical and heavy metal contaminants in white-beaked dolphins (Lagenorhynchus albirostris) and pilot whales (Globicephala melaena) from the coast of Newfoundland, Canada

Polychlorinated biphenyls (∑PCB), DDT isomers (∑DDT), chlordanes (∑CHLOR), toxaphene, chlorobenzenes and hexachlorocyclohexane isomers and seven elements (As, Cd, Cu, Hg, Pb, Se, Zn) were determined in tissues of 41 stranded pilot whales (Globicephala melaena) and 27 ice-entrapped white-beaked dolphins (Lagenorhynchus albirostris) from Newfoundland, Canada. Cadmium, Hg, As and Se were significantly higher in pilot whale kidney and liver than in dolphin tissues. Mercury in liver and blubber, and Cd in kidney, of pilot whales were positively correlated with age. Cadmium levels in both species were much higher than reported for other cetaceans from Canadian east coast waters. Lead concentrations in dolphin kidney and mucles were 5 times higher than in pilot whales. Levels of ∑PCB (sum of 49 congeners) in blubber samples ranged from 31 to 61 mg/kg (lipid wt) in female and male dolphins, respectively, and from 5.6 to 12 mg/kg in female and male pilot whales. ∑DDT and toxaphene were present at similar levels to ∑PCB while mean ∑CHLOR (sum of seven components) ranged from 1.6 to 17 mg/kg in blubber of pilot whales and dolphins, respectively. The presence of high levels of toxaphene in the blubber of both species was unexpected and may be due to increased use of this pesticide during the 1970s. Higher levels of all organochlorine chemicals in blubber, as well as Pb in kidney and muscle, of dolphins than in pilot whales may reflect greater exposure to contaminants because of overwintering and feeding in Gulf of St. Lawrence waters.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in marine mammals in the Canadian North.

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were determined in pooled samples of ringed seal (Phoca hispida) blubber, beluga (Delphinapterus leucas) blubber and polar bear (Ursus maritimus) liver and fat from several areas throughout the Canadian north and compared to mean PCB and HCB levels in the same samples. All seal samples, and all but one polar bear sample, had detectable 2,3,7,8-TCDD at concentrations ranging from 2 to 37 ng/kg, but TCDD was not found in beluga blubber (< 2 ng/kg). All seal samples and one of three beluga samples contained 2,3,7,8-TCDF at levels of 2 to 7 ng/kg, but TCDF was not found in any bear sample. TCDF must therefore be cleared rapidly by polar bears. No other PCDF congeners were found at detection limits of 4 to 8 ng/kg. OCDD concentrations in seal blubber and polar bear samples ranged from not detected (< 8 ng/kg) to 43 ng/kg. No apparent biomagnification of TCDD, OCDD or TCDF occurred from seal to bear fat, similar to previous findings for DDT, and unlike SigmaPCBs and HCB which biomagnified 6- to 17-fold. Highest concentrations of 2,3,7,8-TCDD and OCDD in seals and bears were found in the central Canadian Arctic Archipelago, and lowest were found in Hudson Bay, the reverse of PCB concentration distribution. The reason for higher levels of TCDD and OCDD in the Arctic than in the sub-Arctic is suggested to be trans-polar movement of aerosols with combustion-related origins in Eurasia. Levels of 2,3,7,8-TCDF were more evenly distributed throughout the North, and were positively correlated with PCB, but not with HCB or 2,3,7,8-TCDD levels in seals.

Temporal trends and sources of PCDDs and PCDFs in the Great Lakes : herring gull egg monitoring, 1981-1991

Levels of individual polychlorinated dibenzodioxin (PCDD) congeners were measured in pooled herring gull eggs collected from colonies in the Great Lakes and the St. Lawrence River between 1981 and 1991. Polychlorinated dibenzofurans (PCDFs) were quantified from 1994 to 1991. 2,3,7,8-TCDD, 1,2,3,7,8-PnCDD, 1,2,3,6,7,8-HxCDD, and 2,3,4,7,8-PnCDF were detectable in all samples; 1,2,3,4,6,7,8-HpCDD, OCDD, 2,3,7,8-TCDF, 1,2,3,4,7,8-HxDF, and 1,2,3,6,7,8-HxDF were frequently detected. Eggs from Saginaw Bay, Lake Huron, had the highest PCDD/PCDF levels. LevelB of TCDD, PnCDD, and HxCDD declined in most colonies between 1981 and 1984. There were no obvious temporal trends after 1984. Using multivariate analyses, colonies were separated into two classes based upon differences in egg bioaccumulation patterns

Development of a semi-automated method for non-ortho PCBs : application to Canadian Arctic marine mammal tissues

Abstract A semi-automated carbon column method was developed for the analysis of the non-ortho substituted PCB congeners (3,4,4′-tri; 3,4,4′,5-tetra; 3,3′,4,4′-tetra; 3,3′,4,4′,5-penta; and 3,3′,4,4′,5,5′-hexachlorobiphenyl) (PCBs 37, 81, 77, 126 and 169). The system consisted of an AX21 carbon/glass fibre column with a programmable pumping and valving system. Precision and accuracy measurements indicated the method was reproducible for concentrations greater than 50 ng/kg. Canadian Arctic ringed seal and whale blubber samples were analysed using this method. Parts-pertrillion levels (ng/kg) of non-ortho PCBs were found in all samples. The non-ortho and mono-ortho PCBs (2,3,3′,4,4′-penta; 2,3,4,4′,5-penta; 2,3′,4,4′,5-penta; 2,3,3′,4,4′,5-hexachlorobiphenyl) (PCBs 105, 114, 118 and 156) were the major contributors to total TCDD equivalents in the whale samples (98% in beluga and narwhal) and contributed greater than 50% in the ringed seal samples.

ANALYSIS OF GREAT LAKES HERRING GULL EGGS FOR TETRACHLORODIBENZO-p-DIOXINS

ABSTRACT Methodology previously used for sample clean-up prior to screening for chlorinated dibenzofurans in wildlife tissues was modified and tested for use in the analysis of tetrachlorodibenzo-p-dioxins (TCDDs) in herring gull egg samples. Pooled samples of herring gull eggs collected in 1980 from all of the Great Lakes were analyzed by capillary column, quadrupole GC/MS for TCDDs. The 2,3,7,8-TCDD isomer was found in all samples at levels ranging from 9 to 90 ng/kg (ppt). The identity of 2,3,7,8-TCDD was confirmed by retention time on three capillary columns, and by high resolution mass spectrometry. No other TCDD isomers were present in the samples.

Environmental Contaminants in Eggs of the Common Snapping Turtle (Chelydra serpentina serpentina) from the Great Lakes-St. Lawrence River Basin of Ontario, Canada (1981, 1984)

Abstract Common snapping turtle eggs were collected at nesting sites from two locations in 1981 and eight locations in 1984 in Ontario, Canada, and analyzed for chlorinated hydrocarbons. Nine locations were within the Great Lakes-St. Lawrence River basin and one location, Algonquin Provincial Park, served as a control site outside the basin. Total PCBs ranged from 0.057 to 4.76 mg/kg (wet wt.) among the Great Lakes-St. Lawrence River samples. Mean total PCB concentration at Algonquin Park was 0.187 mg/kg. Eggs from Hamilton Harbour, Port Franks, Bay of Quinte/Murray Canal, and Lake St. Clair were the most contaminated among the ten sample locations. There was statistically significant variation in concentrations of all organochlorine compounds among sites. In some locations, there was high variation in contamination among clutches. A pool of eggs from Hamilton Harbour contained 67 ng/kg of 2378-tetrachlorodibenzo-p-dioxin and 14.0 ng/kg of23478-pentachlorodibenzofuran. Some dioxin congeners were present in turtle eggs at concentrations higher or equal to that in herring gull eggs from Hamilton Harbour. Comprehensive GC/MS analysis of the Hamilton Harbour eggs also revealed the presence of trace amounts of o,p-dicofol, octachlorostyrene, and toxaphene. Geographic variation in contaminant levels in snapping turtle eggs from wetlands is similar to that in spottail shiners and herring gull eggs collected in the pelagic zone of the Great Lakes. This may be due to the consumption of migrant fish by snapping turtles in nearshore wetlands.

Organochlorines, including chlordane compounds and their metabolites, in peregrine-falcon, prairie-falcon, and clapper-rail eggs from the USA

Four compounds present in technical chlordane (trans- and cis-nonachlor, and tentatively MC-2 and MC-5) and three metabolites of chlordane (heptachlor epoxide, oxychlordane, and U-4) were identified by GC/MS in peregrine-falcon (Falco peregrinus anatum) eggs. Levels of Heptachlor epoxide, oxychlordane, trans- and cis-chlordane, trans- and cis-nonachlor, MC-2, and MC-5 were quantified by GC/ECD in peregrine-falcon eggs from the US east coast, Colorado, and California; and in prairie-falcon (Falco mexicanus) and light-footed-clapper-rail (Rallus longirostris levipes) eggs from California. The eggs were collected between 1986 and 1989. Oxychlordane, heptachlor epoxide, trans- and cis-nonachlor, MC-2, and MC-5 were detected in every egg analyzed. Heptachlor, trans-, and cis-chlordane were either not detected, or present at low levels in the eggs. The highest Sigmachlordane levels were found in the East Coast peregrine-falcon eggs at a geometric mean (geom. mean) concentrations of 1800 microg/kg (ppb); the lowest levels of Sigmachlordane were found in the prairie-falcon eggs at a concentration of 120 microg/kg (geom. mean). Of the technical chlordane compounds measured, MC-2 bioaccumulated to the greatest degree. SigmaDDT levels in the falcons ranged from 11 000 microg/kg (geom. mean) in the Colorado samples to 8800 microg/kg (geom. mean) in the East Coast and California peregrines. SigmaDDT levels in the rail eggs were 3000 microg/kg (geom. mean). The highest SigmaPCB levels were found in the East Coast peregrine-falcon eggs at a concentration of 14 000 microg/kg (geom. mean); the lowest levels of SigmaPCB were found in the prairie-falcon eggs at a concentration of 350 microg/kg (geom. mean).