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Assessment of Supercritical Fluid Extraction Use in Whole Sediment Toxicity Identification Evaluations
Citation:
BURGESS, R. M., S. B. Hawthorne, M. PERRON, M. G. CANTWELL, C. B. Grabanski, D. J. Miller, K. T. HO, AND M. C. PELLETIER. Assessment of Supercritical Fluid Extraction Use in Whole Sediment Toxicity Identification Evaluations. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 30(4):819-827, (2011).
Impact/Purpose:
In this investigation, supercritical fluid extraction (SFE) with pure CO2 was assessed as a confirmatory tool in Phase III of whole sediment toxicity identification evaluations (TIEs). Substantial toxicity reductions and contaminant removal from sediments and water samples generated from extracted sediments of up to 99% in two of the contaminated sediments demonstrated SFE effectiveness. Further, toxicological responses for these SFE treated sediments showed comparable results to those from the same sediments treated with the powdered coconut charcoal addition manipulation. These data demonstrated the utility of SFE in Phase III of a whole sediment TIE. Conversely, in one of the contaminated sediments, the SFE treatments had no effect on sediment toxicity while sediment concentrations of PCBs and PAHs were reduced. Overall, SFE treatment was found to be effective for reducing the toxicity and concentrations of NOCs in some contaminated sediments. However, these studies suggest that SFE treatment may enhance toxicity with one of the sediments indicating care must be taken when applying SFE and interpreting the results.
Description:
In this investigation, supercritical fluid extraction (SFE) with pure CO2 was assessed as a confirmatory tool in Phase III of whole sediment toxicity identification evaluations (TIEs). The SFE procedure was assessed on two reference sediments and three contaminated sediments using a combination of toxicological and chemical measurements to quantify effectiveness. Sediment toxicity pre- and post-SFE treatment was quantified with a marine amphipod (Ampelisca abdita) and mysid (Americamysis bahia) while nonionic organic contaminants (NOCs) polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were measured in sediments, overlying waters and interstitial waters. In general, use of SFE with the reference sediments was successful with survival averaging 91% in post-SFE treatments. Substantial toxicity reductions and contaminant removal from sediments and water samples generated from extracted sediments of up to 99% in two of the contaminated sediments demonstrated SFE effectiveness. Further, toxicological responses for these SFE treated sediments showed comparable results to those from the same sediments treated with the powdered coconut charcoal addition manipulation. These data demonstrated the utility of SFE in Phase III of a whole sediment TIE. Conversely, in one of the contaminated sediments, the SFE treatments had no effect on sediment toxicity while sediment concentrations of PCBs and PAHs were reduced. We propose that for some sediments, the SFE treatment may result in the release of otherwise non-bioavailable cationic metals that subsequently cause toxicity to test organisms. Overall, SFE treatment was found to be effective for reducing the toxicity and concentrations of NOCs in some contaminated sediments. However, these studies suggest that SFE treatment may enhance toxicity with one of the sediments indicating care must be taken when applying SFE and interpreting the results.