Using biomarkers to monitorremedial actions at a subtidal estuarine site severely contaminated with polynuclear aromatic hydrocarbons

摘要

Extensive scientific evidence indicates that polycyclic aromatic hydrocarbons (PAHs) and their derivatives are responsible for a variety of serious biological effects in marine fish exposed to such compounds. While much of this information is derived from laboratory studies, there is an increasing body of evidence and biological damage. Several of the most definitive field studies in this regard have been done in Puget Sound, Washington, where one of the most heavily PAH-contaminated sites is Eagle Harbor, on the east side of Bainbridge Island, Studies done by NOAA scientists over the past decade have shown that flatfish residing in Eagle Harbor are at increased risk of developing serious toxicopathic liver diseases, including cancer, and of exhibiting impaired reproductive function and altered physiological responses. The USEPA completed a Remedial Investigation/Feasibility Study, and in December 1991 proposed a phased cleanup of the harbor. In June 1993, under Superfund Removal authority, the USEPA recommended placement of uncontaminated material over the most contaminated area of Eagle Harbor; in late September of 1993 the USEPA began placement of this sediment cap as a means of 1) controlling transport of contaminants; 2) isolating contaminants from marine biota; and 3) providing clean habitat for benthic orgnaisms, thus reducing overall risk of exposure to the contaminants contained in the sediments. This capping process was completed in March 1994, resulting in placement of an approximately three foot thick cap of clean sandy material and associated wood debris over an original area of ca. 54 acres of the most highly cntaminated subtidal sediments within Eagle Harbor. The purpose of this work was to assess whether the sediment cap has reduced PAH exposure in flatfish residing in Eagle Harbor. To accomplish measured in three epibenthic flatfish species: English sole (Pleuronectes vetulus), rock sole (Lepidopsetta bilineata) and starry flounder (Platichthys stellatus). THese measures, also referred to as biomarkers of PAH exposure, are described below. Because of the high rate of metabolism and depuration of PAHs by many species of fish, direct measurement of parent compounds in tissues is not always the best indicator of exposure of fish to PAHs. In fact, the focus on tissue analyses has made it difficult to document exposure of fish to PAHs in contaminated habitats. In recent years, however, methods have been developed for determining such exposure, based on our increased understanding of the mechanisms and pathways of PAH metabolism in fish. In this investigation three methods were used.