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NEAR-COASTAL SEDIMENT AS A HABITAT IN THE GULF OF MEXICO: CHEMICAL QUALITY, TOXICITY, AND BENTHIC COMMUNITY COMPOSITION
Citation:
Lewis, M A. NEAR-COASTAL SEDIMENT AS A HABITAT IN THE GULF OF MEXICO: CHEMICAL QUALITY, TOXICITY, AND BENTHIC COMMUNITY COMPOSITION. Presented at 24th Annual Meeting of SETAC, Austin, TX, Nov 9-13, 2003.
Description:
Sediment quality was determined in a multiyear study for 108 near-coastal sites located in Mississippi, Alabama and Florida. The primary objective of the study was to determine the relative impact of common stressor sources on sediment quality utilizing a weight-of-evidence approach. Other objectives included identifying sensitive assessment techniques and test species and determining the effect of temporal variation on the results and the predictability of sediment quality guidelines. Sampling sites were located in reference areas and those impacted by 11 wastewaters and stormwater runoff from urban areas, golf courses and agricultural fields. Contaminant concentrations in surface water and sediment were determined for 12 trace metals, 25 chlorinated pesticides, 18 PCB congeners and 24 PAH compounds. Acute and chronic whole sediment and pore water toxicity tests were conducted with six species of estuarine invertebrates. Phytotoxicity was determined using three vascular plants and the genotoxic potential of the pore waters was determined using a microbial assay. Benthic community composition was also analyzed. Sediment impacts occurred in near-field areas and usually dissipated seaward. Exceedances of sediment quality guidelines, toxicity, phytotoxicity and genotoxicity were greater in areas receiving urban runoff. Grass shrimp were the most sensitive animal test species in the bioassays. Genotoxicity and phytotoxicity were relatively common but the results did not parallel those for standard animal test species exposed to the same media. This finding is important in the context of understanding the predictive value of these guidelines in the sediment hazard assessment process.
Will be oral presentation.