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Field Characterization of Potential Reference Sediments in the Gulf of Mexico: Chemical and Biological Quality
Citation:
Lewis, M A., P S. Harris, J G. Campbell, R L. Quarles, D D. Dantin, S S. Foss, AND J C. Moore. Field Characterization of Potential Reference Sediments in the Gulf of Mexico: Chemical and Biological Quality. SOIL AND SEDIMENT CONTAMINATION: AN INTERNATIONAL JOURNAL. CRC Press LLC, Boca Raton, FL, (15(1)):1-20, (2006).
Impact/Purpose:
To consider possible candidates for regional reference areas in the Gulf of Mexico using chemical quality, toxicity and benthic community composition in sediments
Description:
Lewis, Michael A., Jed G. Campbell, Peggy S. Harris, Darrin D. Dantin, Steve S. Foss, Robert L. Quarles, James C. Moore and Cynthia A. Chancy. Submitted. Characterization of Potential Reference Areas in the Gulf of Mexico: Near-Coastal Sediment Chemical and Biological Quality. Environ. Monit. Assess. 31 p. (ERL,GB 1207).
Baseline information on the chemical and biological quality of sediments is provided for 12 sites at six coastal locations in the northern Gulf of Mexico which were considered possible candidates for regional reference areas. Chemical quality, toxicity and benthic community composition were determined for sediments collected three times from each site during an approximate one year period. Contaminants in the usually sand-dominated sediments exceeded individual threshold effects level guidelines proposed for Florida coastal areas in approximately 31% of the samples collected from 8 of 12 sites. No probable effects level guidelines were exceeded. Mortality exceeding 20% occurred for 16% or less of the sediment samples collected from each site. No significant chronic toxicity occurred after 28 d to L. plumulosus. Approximately, 11% and 17% of the sediments were classified as poor or marginal based on low taxa abundance and diversity index values, respectively. Sediment quality at many sites was less degraded than that for several coastal areas receiving documented point and non-point source contaminants. This suggests their suitability as reference sediments but further confirmation is needed. The results of this survey reflect the complexity in field verification of reference conditions for near-coastal sediments due largely to the natural spatial heterogenicity in their physical, biological and chemical characteristics which can affect conclusions concerning environmental quality.