title: Snapping Turtles (Chelydra serpentina) from Canadian Areas of Concern across the southern Laurentian Great Lakes: Chlorinated and brominated hydrocarbon contaminants and metabolites in relation to circulating concentrations of thyroxine and vitamin A.
abstract: The metabolites of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), as well as other halogenated phenolic contaminants (HPCs) have been shown to have endocrine-disrupting properties, and have been reported with increasing frequency in the blood of wildlife, and mainly in mammals and birds. However, little is known about the persistence, accumulation and distribution of these contaminants in long-lived freshwater reptiles. In the present study, in addition to a large suite of chlorinated and brominated contaminants, metabolites and HPCs, we assessed and compared hydroxylated (OH) PCBs and OH-PBDEs relative to PCBs and PBDEs, respectively, in the plasma of adult male common snapping turtles (Chelydra serpentina). Blood samples were collected from 62 snapping turtles (2001-2004) at 12 wetland sites between the Detroit River and the St. Lawrence River on the Canadian side of the Laurentian Great Lakes of North America. Turtles were sampled from sites designated as Areas of Concern (AOCs) and from a relatively clean reference site in southern Georgian Bay (Tiny Marsh), Lake Huron. Plasma concentrations of Σ46PCB (10-340 ng/g wet weight (ww)) and Σ28OH-PCB (3-83 ng/g ww) were significantly greater (p<0.05) in turtles from the Turkey Creek and Muddy Creek-Wheatley Harbour sites in Lake Erie compared with the reference site turtles. The HPC, pentachlorophenol (PCP), had a mean concentration of 9.6±1.1 ng/g ww. Of the 28 OH-CB congeners screened for, 4-OH-CB187 (42±7 ng/g ww) was the most concentrated of all HPCs measured. Of the 14 OH-BDE congeners examined, four (4'-OH-BDE17, 3-OH-BDE47, 5-OH-BDE47 and 4'-OH-BDE49) were consistently found in all plasma samples. p,p'-DDE was the most concentrated of the 18 organochlorine pesticides (OCPs) examined. The mean concentrations of circulating total thyroxine (TT4), dehydroretinol and retinol in the plasma of the male snapping turtles regardless of sampling site were 5.4±0.3, 81±4.7 and 291±13 ng/mL, respectively. Significant (p<0.05) negative (e.g. cis-chlordane) or positive (e.g. BDE-99) correlations between some of the target contaminants and TT4, dehydroretinol or retinol were observed. To our knowledge, we report for the first time on HPC (e.g. OH-PCBs) and methylsulfonyl- (MeSO2-) PCB metabolite contaminants in the plasma of any freshwater turtle or freshwater reptilian species. Our findings also show that the accumulation of OH-PCBs, MeSO2-PCBs, OH-PBDEs and some OCPs in the snapping turtles from Lake Erie and Lake Ontario (in 2001-2004) had the potential for eliciting endocrine disruption. Exposure to these contaminants and associated adverse effects on the endocrine system in freshwater reptiles and the related mechanisms require further investigation.
authors.affiliation: Ecotoxicology and Wildlife Health Division, Science and Technology Branch, Environment Canada, National Wildlife Research Centre, Carleton University, Ottawa, Ontario, Canada K1A 0H3. Electronic address: robert.letcher@ec.gc.ca.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Letcher
authors.affiliation: Richardson College for the Environment, Environmental Studies Program and Department of Chemistry, University of Winnipeg, Winnipeg, MB, Canada R3B 2E9.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Lu
authors.affiliation: Ecotoxicology and Wildlife Health Division, Science and Technology Branch, Environment Canada, Canada Centre for Inland Waters, Burlington, Ontario, Canada L7S 1A1.
authors.forename: Shane R
authors.initials: SR
authors.lastname: de Solla
authors.affiliation: Chemistry Matters Inc., Calgary, AB, Canada.
authors.forename: Courtney D
authors.initials: CD
authors.lastname: Sandau
authors.affiliation: Ecotoxicology and Wildlife Health Division, Science and Technology Branch, Environment Canada, Canada Centre for Inland Waters, Burlington, Ontario, Canada L7S 1A1.
authors.forename: Kimberly J
authors.initials: KJ
authors.lastname: Fernie
mesh_terms: D000818:Animals; D002170:Canada; D052244:Endocrine Disruptors / Q000097:blood* / Q000378:metabolism; D004784:Environmental Monitoring / Q000379:methods*; D006114:Great Lakes Region; D006842:Hydrocarbons, Brominated / Q000097:blood* / Q000378:metabolism; D006843:Hydrocarbons, Chlorinated / Q000097:blood* / Q000378:metabolism; D008297:Male; D013974:Thyroxine / Q000097:blood*; D014426:Turtles / Q000097:blood*; D014801:Vitamin A / Q000097:blood*
chemical_list: D052244:Endocrine Disruptors; D006842:Hydrocarbons, Brominated; D006843:Hydrocarbons, Chlorinated; D014801:Vitamin A; D013974:Thyroxine
keywords: Halogenated phenolic compounds; Laurentian Great Lakes; Metabolites; OCPs; PBDEs; PCBs; Plasma; Snapping turtle; Thyroxine; Vitamin A