W9 PM Residual Oil and its Effects
Wednesday, 16 November 2005: 1:50 PM - 5:30 PM in 339-340

(RIC-1117-874827) Corroboration and significance of elevated CYP1A in Sea Otters and Harlequin ducks from chronic exposure to the Exxon Valdez spill in Prince William Sound.

Rice, S¹, Short, J¹, Carls, M¹, Springman, K², Bodkin, J ³, Ballachey, B³, ¹ NOAA, NMFS, Auke Bay Lab, Juneau, Alaska, USA² U C Davis, Center for Health and Environment, Davis, CA, USA³ USGS, Anchorage, Alaska, USA

ABSTRACT- Elevated levels of cytochrome P4501A (CYP1A) have been observed in several species in post-spill areas of Prince William Sound, site of the 1989 Exxon Valdez oil spill. In later years, as the oil level diminished, the conclusion that the Exxon Valdez oil spill was responsible for the elevated CYP1A response was challenged by Exxon contractors, who attributed the elevated levels of this enzyme to other sources. Much of the controversy was stimulated by findings 10-15 years after the spill: (1) significant pockets of sub-surface Exxon Valdez oil in the middle- to lower-intertidal zone areas, where mussels, clams, and other prey species for intertidal predators are found; (2) elevated CYP1A levels of intertidal predators (Sea Otters and Harlequin ducks); and (3) slow population recovery of these predators in the areas with greatest oil persistence. Other possible sources of P4501A inducers have been suggested, but the recent evidence from large scale field deployment of SPMDs in 2004 accumulating large quantities of PAH from Exxon Valdez oil spill sites, and neither PAH or POPs from non-oiled sites, including historical human use sites, corroborates the conclusion that Exxon Valdez oil is responsible for long term impacts to these species. Further, CYP1A was induced from the extracts of the SPMDs from oiled sites, but was not at other sites, and corroborates that lingering oil was responsible for the elevated CYP1A in Sea Otters and Harlequin ducks from oiled areas. Not only does elevated levels of CYP1A indicate continued chronic exposure to Exxon Valdez oil in Prince William Sound, chronic elevated levels also predict population level impacts in Sea Otters and Harlequin ducks.

Key words: Exxon Valdez Oil Spill, CYP1A, Chronic Exposure, SPMD