Organochlorine pesticides, PCBs, dibenzodioxin, and furan concentrations in common snapping turtle eggs (Chelydra serpentina serpentina) in Akwesasne, Mohawk Territory, Ontario, Canada

Subsamples of eight clutches of common snapping turtle eggs (Chelydra serpentina serpentina) were collected from four sites from the territory of the Mohawk Nation, Akwesasne, on the shore of the St. Lawrence River. Egg contents were analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), dibenzodioxins, and furans. The sites were 2 to 13 km downstream from PCB-contaminated landfill sites. Maximum concentrations of total PCBs in snapping turtle clutches were extremely high, and ranged from 2 378.2 ng/g to 737 683 ng/g (wet weight) and are among the highest recorded in any tissue of a free-ranging animal. Similarly, in a pooled sample of eggs from all four sites, the summed concentrations of non-ortho PCBs (n = 6 congeners) was also very high at 54.54 ng/g and the summed dioxin and furan concentrations (n = 11 congeners) was 85.8 ng/g. Sum organochlorine pesticide levels varied from 28 to 2,264 ng/g among the four sites. The levels of PCBs found in turtle eggs exceed concentrations associated with developmental problems and reduced hatching success in snapping turtles and other species and also exceed the Canadian tissue residue guidelines for toxic equivalency concentrations. The extremely high levels of organochlorine contaminants demonstrate the high degree of contamination in the environment in the Akwesasne area.