title: Probabilistic risk assessment of reproductive effects of polychlorinated biphenyls on bottlenose dolphins (Tursiops truncatus) from the Southeast United States Coast.
abstract: High levels of polychlorinated biphenyls (PCBs) have been reported in the tissues of some species of marine mammals. The high concentrations are of concern because a growing body of experimental evidence links PCBs to deleterious effects on reproduction, endocrine homeostasis, and immune system function. Much of the recent research has focused on determining the exposure of marine mammal populations to PCBs, but very little effort has been devoted to the actual risk assessments that are needed to determine the expected impacts of the documented exposures. We describe a novel risk assessment approach that integrates measured tissue concentrations of PCBs with a surrogate dose-response relationship and leads to predictions of health risks for marine mammals as well as to the uncertainties associated with these predictions. Specifically, we use PCB tissue residue data from three populations of bottlenose dolphins (Tursiops truncatus), study the feasibility of published dose-response data from a surrogate species. and combine this information to estimate the risk of detrimental reproductive effects in female dolphins. Our risk analyses for dolphin populations near Beaufort (NC, USA), Sarasota (FL, USA), and Matagorda Bay (TX, USA) indicate a high likelihood that reproductive success, primarily in primiparous females, is being severely impaired by chronic exposure to PCBs. Excess risk of reproductive failure, measured in terms of stillbirth or neonatal mortality, for primiparous females was estimated as 60% (Beaufort), 79% (Sarasota), and 78% (Matagorda Bay). Females of higher parity, which have previously off-loaded a majority of their PCB burden, exhibit a much lower risk.
authors.affiliation: National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Road, Charleston, South Carolina 29412-9110, USA. lori.schwacke@noaa.gov
authors.forename: Lori H
authors.initials: LH
authors.lastname: Schwacke
authors.forename: Eberhard O
authors.initials: EO
authors.lastname: Voit
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Hansen
authors.forename: Randall S
authors.initials: RS
authors.lastname: Wells
authors.forename: Greg B
authors.initials: GB
authors.lastname: Mitchum
authors.forename: Aleta A
authors.initials: AA
authors.lastname: Hohn
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Fair
mesh_terms: D000818:Animals; D004289:Dolphins / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000009:adverse effects*; D005260:Female; D005313:Fetal Death / Q000209:etiology / Q000662:veterinary*; D006304:Health Status; D010298:Parity; D011078:Polychlorinated Biphenyls / Q000009:adverse effects*; D011157:Population Dynamics; D011247:Pregnancy; D012098:Reproduction / Q000187:drug effects*; D018570:Risk Assessment; D014018:Tissue Distribution; D014481:United States
chemical_list: D004785:Environmental Pollutants; D011078:Polychlorinated Biphenyls