Grantee Research Project Results
Persistent Organic Pollutants in the Puget Sound Ecosystem: Temporal Patterns in Excretion of POPs and Associated Endocrine Disruption in Free-Ranging Killer WhalesEPA Grant Number: FP917352
Title: Persistent Organic Pollutants in the Puget Sound Ecosystem: Temporal Patterns in Excretion of POPs and Associated Endocrine Disruption in Free-Ranging Killer Whales
Investigators: Lundin, Jessica I
Institution: University of Washington
EPA Project Officer: Cobbs-Green, Gladys M.
Project Period: September 1, 2011 through August 31, 2014
Project Amount: $126,000
RFA: STAR Graduate Fellowships (2011)
Research Category: Fellowship - Pesticides and Toxic Substances , Academic Fellowships
The Puget Sound ecosystem of Washington State has been riddled with human impacts. Exposure to persistent organic pollutants (POPs) has been listed as a primary risk factor for the endangered Southern Resident killer whale (Orcinus orca) population that subsists in these waters. POPs are a group of toxic chemicals associated with adverse health effects including endocrine disruption, neurotoxicity and immune system toxicity; the POPs being evaluated in this study include PBDEs, PCBs, DDTs, chlordanes, HCHs and HCB. The objectives of this research project are to use non-invasive methods to evaluate temporal patterns of toxicant excretion in top-level piscivores, and to assess associated disruption of the endocrine system through biologic measurements and an evaluation of reproductive success.Approach:
This study uses unique sampling methods to noninvasively measure endocrine indices and contaminant levels in a free-ranging killer whale population. Scat ( fecal) samples are collected from killer whales through the employment of specially trained scat detection dogs. The Conservation Canines are able to locate samples floating on the water from as far away as a nautical mile from the whales, increasing sample size while decreasing sampling bias. Laboratory analyses of the samples include toxicant level quantification using GC/ MS and enzyme immunoassays, hormone radioimmunoassays and DNA confirmation of species, individual and sex. The toxicant data will be used to assess the level of contamination in this endangered population. Predictive factors for variation in contaminant levels, such as gender, season and prey availability also will be evaluated. This study will contribute to the understanding of endocrine disruption associated with toxicant exposure by evaluating the relationship between toxicant and thyroid hormone levels measured from the same sample. Population-based and individual-based models will be used to evaluate the association of environmental contaminant levels and other biologic measures with population success.Expected Results:
The pollutants of interest are lipophilic; as such, these toxicants are generally stored in adipose tissue and released into circulation during times of nutritional shortage. The POP contaminate levels detected in the feces are expected to demonstrate an inverse relationship with the seasonal availability of salmon, as evaluated using salmon population estimates and concentration of fecal thyroid and glucocorticoid hormones (markers of nutritional stress). However, the expected inverse relationship between POP and thyroid hormone levels is expected to be non-linear. An accelerated decrease in the level of thyroid hormone is expected as the POP contaminant level increases due to endocrine disruption activity of the halogenated compounds. Lastly, population growth models adapted for this endangered population are expected to demonstrate an inverse correlation between reproductive success and POP contaminant level.
Potential to Further Environmental/ Human Health Protection
This study has the potential to have an important environmental and economic influence for the region by helping to inform the U.S. and Canadian governments, other scientists and nongovernment agencies. The measured outcome data from this study may be used to improve the effectiveness of remediation efforts and management approaches that would support priority Puget Sound ecosystem protection and restoration goals. Understanding POP contamination in Puget Sound is important for all who depend on the health of this ecosystem, including: subsistence-oriented consumer groups such as First Nations communities, sport-fishing families, and the public who rely on commercial fish markets, as well as killer whales, and other marine species.Supplemental Keywords:
persistent organic pollutants, PCB, PBDE, DDT, toxic chemicals, Salish Sea, Puget Sound, Southern Resident killer whales, endangered species, thyroid hormones, steroid hormones, detection dogs