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Aqueous CO{sup 2} vs. aqueous extraction of soils as a preparative procedure for acute toxicity testing

Conference ·
OSTI ID:37379
;  [1]
  1. Oklahoma State Univ., Stillwater, OK (United States). Water Quality Research Lab.
This study was to determine if contaminated soils extracted with supercritical CO{sup 2} (SFE) would yield different results from soils extracted with an aqueous media. Soil samples from an abandoned oil refinery were subjected to aqueous and SFE extraction. Uncontaminated control sites were compared with contaminated sites. Each extract was analyzed for 48 hour acute Ceriodaphnia LC50s and Microtox{reg_sign} EC50s. Comparisons were then made between the aqueous extracts and the SFE extracts. An additional study was made with HPLC chromatographs of the SFE contaminated site extracts to determine if there was a correlation between LC50 results and peak area of different sections of the chromatograph. The 48 hour Ceriodaphnia LC50 of one contaminated site showed a significant increase in toxicity with the supercritical extract compared to the aqueous extract. All contaminated sites gave toxic responses with the supercritical procedure. The Microtox{reg_sign} assay showed a toxic response with 2 of the 3 contaminated sites for both aqueous and SFE extracts. Results indicate that the Ceriodaphnia assays were more sensitive than Microtox{reg_sign} to contaminants found in the refinery soil. SFE controls did not show adverse effects with the Ceriodaphnia, but did have a slight effect with Microtox{reg_sign}. The best correlation (r{sup 2} > 0.90) between the Ceriodaphnia LC50s and the peak areas of the chromatographs was obtained for sections with an estimated log K{sub ow} of 1 to 5. SFE extraction provided a fast, efficient and inexpensive method of collecting and testing moderately non-polar to strongly non-polar organic contaminants from contaminated soils.
OSTI ID:
37379
Report Number(s):
CONF-9410273--
Country of Publication:
United States
Language:
English