title: The role of organochlorines in cancer-associated mortality in California sea lions (Zalophus californianus).
abstract: Wild California sea lions (Zalophus californianus) have an unusually high prevalence of neoplasms (18% of stranded dead adults) and high levels of contaminants. The contribution of organochlorine (OC) tissue burdens to the probability of sea lions dying from carcinoma was explored using a logistic regression model. Levels of PCBs and DDTs were determined in blubber of sea lions diagnosed with metastatic carcinoma and animals that had died from non-carcinoma-related incidents (e.g., gunshot, domoic acid poisoning). Animals with carcinoma had higher mean concentrations (based on wet weight) of PCBs and DDTs (more than 85% and 30% higher, respectively) in blubber than did sea lions without carcinoma; the highest concentrations of OCs in the sea lions affected with carcinoma were measured in the males. Blubber thickness was significantly different between the two groups of sea lions, but after controlling for this difference, there was still a significant effect of PCBs, but not DDTs, on the probability of sea lions dying with carcinoma. Age, sex, mass and length did not affect the probability of dying from carcinoma.
authors.affiliation: Environmental Conservation Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, WA 98112, USA. gina.ylitalo@noaa.gov
authors.forename: Gina M
authors.initials: GM
authors.lastname: Ylitalo
authors.forename: John E
authors.initials: JE
authors.lastname: Stein
authors.forename: Tom
authors.initials: T
authors.lastname: Hom
authors.forename: Lyndal L
authors.initials: LL
authors.lastname: Johnson
authors.forename: Karen L
authors.initials: KL
authors.lastname: Tilbury
authors.forename: Ailsa J
authors.initials: AJ
authors.lastname: Hall
authors.forename: Teri
authors.initials: T
authors.lastname: Rowles
authors.forename: Denise
authors.initials: D
authors.lastname: Greig
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Lowenstine
authors.forename: Frances M D
authors.initials: FM
authors.lastname: Gulland
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D002140:California; D002277:Carcinoma / Q000139:chemically induced* / Q000401:mortality / Q000662:veterinary*; D002851:Chromatography, High Pressure Liquid; D004785:Environmental Pollutants / Q000633:toxicity*; D008401:Gas Chromatography-Mass Spectrometry; D006843:Hydrocarbons, Chlorinated / Q000633:toxicity*; D016015:Logistic Models; D046070:Sea Lions
chemical_list: D004785:Environmental Pollutants; D006843:Hydrocarbons, Chlorinated