Organic contaminants in snapping turtle (Chelydra serpentina) populations from southern Ontario, Canada

Organochlorine contaminant levels were measured in 78 adult snapping turtles collected from 16 sites in southern Ontario, Canada in 1988/89 to evaluate the risk to humans of consuming snapping turtles. Significant differences in turtle contaminant levels were observed among sites. Mean levels in muscle, at all sites, were below fish consumption guidelines for total polychlorobiphenyls (PCBs), total DDT and mirex. However, contaminant levels in older turtles from some sites exceeded guideline values. Multivariate statistical techniques indicated the existence of a highly significant relationship between contaminant levels in adult female turtles and their eggs. Multivariate techniques also identified differences in contaminant composition in adult snapping turtles from sites in the Great Lakes where differences in reproductive success have been previously observed. The mono-ortho substituted PCB congener 2,3,4,3′,4′-pentachlorobiphenyl (IUPAC #105) may be an important contributor to the toxic burden of snapping turtle populations

Organochlorine contaminants in a terrestrial foodweb on the Niagara Peninsula, Ontario, Canada 1987-89

During 1987-89, organochlorine contaminant levels were measured in American kestrel (Falco sparverius) eggs and in other components of the terrestrial ecosystem in Ontario, Canada. The extent to which these samples were contaminated with DDE varied geographically. Wet weight levels of DDE were greater in eggs from American kestrels (10.8 mg/kg), American robins (Turdus migratorius) (17.3 mg/kg), European starlings (Sturnus vulgaris) (8.8 mg/kg), and eastern bluebirds (Sailia sailis) (7.6 mg/kg) and in samples of earthworms (Lumbricus sp.) (0.6 mg/kg), soil (0.3 mg/kg) and vegetation (8.7 μg/kg) originating from the northern portion of the Niagara Peninsula than elsewhere in southern Ontario. This area is an intensive fruit growing region which received heavy applications of DDT in the past. DDT and its metabolites persist in the soil of this area and are transferred to the biotic community via trophic interactions. DDE may continue to pose a regional hazard to wildlife as a result of these toxic "hot-spots." In 1987 and 1988, kestrel reproductive success was lower on the northern Niagara Peninsula than at a site in southwestern Ontario. However, it was not possible to attribute this reduced reproductive success to environmental contaminants

Concentrations and distributions of polychlorinated biphenyls, including non-ortho congeners, in mink populations from southern Ontario

Concentrations and distributions of polychlorinated biphenyls and organochlorines were quantified in 79 wild mink livers as part of a study to assess the use of mink as biomonitors of organic contaminants in wetlands. Samples were collected from fifteen southern Ontario townships, including townships bordering the Great Lakes and further inland, to quantify the relative importance of the Great Lakes food webs on contaminant levels observed in feral mink populations. The mink population in Mersea Township (Chatham District), bordering Lake Erie, was found to have significantly higher concentrations (1,797 μg/kg total PCB, wet weight) of many of the contaminants quantified. Reach Township (Lindsay District), inland from Lake Ontario, had significantly lower concentrations (39 μg/kg total PCB, wet weight). Multivariate analysis of organochlorine data demonstrated little spatial difference among PCB congener distribution patterns, except a greater proportion of total PCB was contributed by PCB 118 in mink taken from Wainfleet (Niagara District) and Reach Townships. The more toxic non-ortho PCBs were rarely found above levels of detection (0.05 μg/kg), and PCBs 126 and 118 represented over 90% of the estimated TEQ. In the more contaminated areas, PCB concentrations were sufficiently high to potentially affect the fitness of mink populations