Snapping turtles (Chelydra serpentina) as bioindicators in Canadian areas of concern in the Great Lakes Basin. II. Changes in hatching success and hatchling deformities in relation to persistent organic pollutants.

Hatching success and deformities in snapping turtle hatchlings (Chelydra serpentina) were evaluated using eggs collected from 14 sites in the Canadian lower Great Lakes, including Areas of Concern (AOC), between 2001 and 2004. Eggs were analyzed for PCBs, PBDEs, and pesticides. Between 2002 and 2004, hatchling deformity rates were highest in two AOCs (18.3-28.3%) compared to the reference sites (5.3-11.3%). Hatching success was poorest in three AOCs (71.3-73.1%) compared to the reference sites (86.0-92.7%). Hatching success and deformity rates were generally poorer in 2001 compared to 2002-2004, irrespective of the study location and could be due to egg handling stress in 2001. Hatching success and deformities were generally worst from the Wheatley Harbour, St. Lawrence River (Cornwall), Detroit River, and Hamilton Harbour AOCs. Associations between contaminant burdens with embryonic development were sufficiently poor that the biological relevance is questionable. Stressors not measured may have contributed to development abnormalities.

Contaminant residues in snapping turtle (Chelydra s. serpentina) eggs from the Great Lakes-St. Lawrence River basin (1999 to 2000).

To determine temporal and geographic variations of environmentally persistent pollutants, the concentrations of several contaminants were measured in snapping turtle eggs in 1999 and 2000. Contaminants included polychlorinated biphenyls (PCBs), non- ortho PCBs, polychlorinated dibenzodioxins and furans, organochlorine pesticides, and total mercury. Egg collection sites within the St. Lawrence Area of Concern (AOC) and the Territory of Akwesasne included Turtle Creek, Snye Marsh, and Raquette River. Additional contaminated sites were Gray's Creek (within the St. Lawrence AOC boundary), Coote's Paradise (Hamilton Harbour AOC), and the Territory of Walpole Island (St. Clair AOC). Reference sites were Lake Sasajewun, Algonquin Provincial Park in central Ontario, and in close proximity to the St. Lawrence Area AOC, Hoasic Creek and Cooper Marsh. Eggs from clutches collected from Akwesasne contained the highest concentrations of contaminants. Mean total PCB concentrations for Akwesasne clutches ranged from 1,900 to 61,000 ng/g wet weight (w.w.), which was 360 to 3,100 times higher than the mean concentrations at the reference sites. The high levels of contaminants in eggs, from sites within Akwesasne, were consistent with trends reported in the past and reflect the influence of the proximity of heavy industry. Current contaminant concentrations in clutches from Coote's Paradise are comparable with those recorded in 1989 and 1990 but are 200 to 800 times lower than concentrations reported in 1984 and 1988. Eggs from Lake Sasajewun contained relatively low contaminant levels, which is consistent with atmospheric deposition. Our results support that snapping turtles are good indicators of temporal and geographic contaminant trends.