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SEDIMENT TOXICITY EVALUATION OF EXTRACTS OF ORGANIC CHEMICALS FROM CONTAMINATED SEDIMENTS: EVALUATION OF AN EXPERIMENTAL APPROACH
Citation:
Heinis, L J., D. R. Mount, V R. Mattson, AND S A. Diamond. SEDIMENT TOXICITY EVALUATION OF EXTRACTS OF ORGANIC CHEMICALS FROM CONTAMINATED SEDIMENTS: EVALUATION OF AN EXPERIMENTAL APPROACH. Presented at Midwest Regional SETAC Meeting, Racine, WI, April 26-27, 2001.
Description:
Most solid-phase sediment TIE techniques for organic chemicals have been focused on the addition of sorbents, such as the carbonaceous resin, Ambersorb 1500. While these sorbents have shown some promise for indicating when non-polar organic chemicals may be contributing to toxicity, they are not amenable to toxicity-based fractionation to determine the identity of specific causative toxicants. Direct solvent extraction of sediments followed by water column toxicity tests is also problematic, becuase the partitioning influence of sediment organic carbon is lost. To address these issues, we have developed an approach combining solvent extraction with a sediment spiking technique to provide a procedure for isolation, fractionation, and toxicity testing of nominal concentration of 64.7 mg/kg wwt. Following equilibration, the bulk sediment was extracted with methylene chloride to recover the fluoranthene. This organic extract was then used to fortify clean sediment and allowed to equilibrate. Oligochaetes (Lumbriculus variegatus) were exposed to dilutions of the extract-fortified sediment and the original fluoranthene-spiked sediment for 10 days. Following sediment exposure, oligochaetes were removed to clean water and exposed to UV-A at intensities of 15 and 50 u W/cm2. Photo-activated toxicity was observed in organisms exposed to both sediment types at similar concentrations of fluoranthene. The application of this approach in sediment TIE is discussed.