The Chemical Baseline as a Key to Defining Continuing Injury and Recovery of Prince William Sound

Abstract

ABSTRACT Studies of records and data pertaining to anthropogenic and natural sources of petroleum, and specifically of the polycyclic aromatic hydrocarbons (PAH), have indicated a generally constant background, with episodic input spikes of bioavailable PAH to the marine environment of Prince William Sound (PWS), Alaska. The Exxon Valdez oil spill (EVOS) was one such PAH spike. However, hundreds of smaller spills, occurring prior to and since the EVOS, contribute a background of bioavailable petrogenic PAH to PWS. The widespread historical and contemporary uses of PWS by man have left chronic, sizeable, and widespread petrogenic and pyrogenic PAH fingerprints and bioavailable PAH at many locations in PWS. Evidence from mussel samples, taken both prior to and since EVOS, and from subtidal sediments, indicates that bioavailable PAH are a constant feature of the PWS system. While EVOS may continue to add some bioavailable PAH to highly localized areas, most PAH inputs to the PWS marine environment are unrelated to EVOS. Such findings indicate that biological, sublethal effects studies, which rely on tissue body burdens and biomarkers as leading indicators of continuing effects from EVOS (e.g. CYP1A-P450, etc.) may have been misinterpreted, as they are confounded by this easily detectable, significant, and continuing background of bioavailable PAH. Therefore measurements of exposure to PAH as indicating lingering effects from EVOS, 13 years after the spill, are speculative and ignore the baseline PAH from non-EVOS inputs.