Are sea otters being exposed to subsurface intertidal oil residues from the Exxon Valdez oil spill?

• Published in: Marine pollution bulletin Vol. 62; no. 3; pp. 581 - 589
• Main Authors: Boehm, P.D., Page, D.S., Neff, J.M., Brown, J.S.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.03.2011; Elsevier
• Subjects: Alaska; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Chemical Hazard Release; clams; direct contact; Ecotoxicology, biological effects of pollution; Enhydra lutris; Environmental Exposure - analysis; Environmental Exposure - statistics & numerical data; Exxon Valdez; Feeding Behavior; foraging; Fundamental and applied biological sciences. Psychology; habitats; littoral zone; Mammalia; Marine; Marine and brackish environment; oil spills; oils; Otters; Petroleum - analysis; Polycyclic aromatic hydrocarbons; Sea water ecosystems; Sediment contamination; sediments; shorelines; surveys; Synecology; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Water Pollutants, Chemical - analysis; water pollution; Alaska; INE, USA, Alaska, Alaska Gulf, Prince William Sound; Sediment contamination; Polycyclic aromatic hydrocarbons; Enhydra lutris; Exxon Valdez; Oil spill; Fissipedia; Carnivora; Hydrocarbon; Polycyclic aromatic compound; Sediments; Contamination; Persistent organic pollutant; Marine environment; Vertebrata; Intertidal zone; Mammalia; Oil; Residue; Subsurface; Organic compounds
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2010.11.026

► Oil residues (SSOR) are sequestered in subsurface layers at some beaches. ► Beach features that promote sequestration of SSOR are not found where otters dig. ► Sea otters dig intertidal foraging pits in areas without SSOR. ► PAHs from SSOR are not being mobilized to contaminate intertidal animals. ► No evidence of exposure to SSOR through direct contact during pit-digging. Twenty years after the Exxon Valdez oil spill, scattered patches of subsurface oil residues (SSOR) can still be found in intertidal sediments at a small number of shoreline locations in Prince William Sound, Alaska. Some scientists hypothesize that sea otters continue to be exposed to SSOR by direct contact when otters dig pits in search of clams. This hypothesis is examined through site-specific examinations where SSOR and otter-dug pits co-occur. Surveys documented the exact sediment characteristics and locations on the shore at the only three subdivisions where both SSOR and otter pits were found after 2000. Shoreline characteristics and tidal heights where SSOR have persisted are not suitable habitat for sea otters to dig pits during foraging. There is clear separation between areas containing SSOR and otter foraging pits. The evidence allows us to reject the hypothesis that sea otters encounter and are being exposed by direct contact to SSOR.