Bacterial mutagenicity and acute toxicity of solvent and aqueous extracts of soil samples from an abandoned chemical manufacturing site

Abstract

Using a grid pattern, a total of 50 soil borings (DCT 1 through DCT 50) were collected from an abandoned chemical manufacturing facility. Split samples were obtained from six cores collected from a centralized location near a former wastewater lagoon. An additional sample from the 2.1‐ to 2.4‐m depth of core DCT 20 was obtained as representative of the waste present on site. Three subsamples from each of the six cores or a total of 18 samples were sequentially extracted with methylene chloride and methanol for testing in mutagenicity and acute toxicity assays. A separate batch extraction with water was conducted and evaluated, using both chemical and biological test methods. The maximum mutagenic response was 3,237 net revertants induced with metabolic activation by 1 mg of the methanol extract of the 0‐ to 0.6‐m depth at sampling location DCT 32. The water extract of the 0‐ to 0.6‐m depth at sampling location DCT 32 induced 737 net revertants per mg. At sampling location DCT 24, the water extract induced 0.74, 1.32, and 2.5 toxic units in the Microtox® assay and 935, 69, and 39 net revertants per mg in the mutagenicity assay at the 0‐ to 0.3‐, 1.2‐ to 1.4‐, and 2.1‐ to 2.4‐m depths, respectively. The chemical analysis of the samples from location DCT 24 indicated that the concentration of 2,3,6‐trichlorobenzene acetic acid ranged from 16 ppm in the 0‐ to 0.3‐m depth and to 0.95 ppm and below the detection limits at the 1.2‐ to 1.4‐ and 2.1‐ to 2.4‐m depths. The methanol extract of the soil from the 0‐ to 0.3‐m depth induced 19.2 toxic units in the acute toxicity assay and 1,467 net revertants in the mutagenicity assay. These results suggest that the most accurate site assessment is obtained when a water extract is evaluated to measure leaching potential and a solvent extract is evaluated to determine the relative total hazard of the sample. In addition, the combined use of chemical analysis, mutagenicity, and acute toxicity bioassays provides more accurate information from which to make a risk assessment.

Application of Chemically Accelerated Biotreatment to Reduce Riskin Oil-Impacted Soils

“…However, this trend did not continue; the soil that contained the second greatest concentration of PAH (SoCal 3) was one of the least toxic samples. Previous studies completed on contaminated soils and sediments have also shown lack of consistent correlation between the results of chemical analyses and Microtox toxicity (True and Heyward 1990, Donnelly et al 1991, Jacobs et al 1993, as well as toxicity determined with fish and invertebrates (Athey et al 1989, Hoke et al 1990. Vigorous physical and chemical methods of contaminant extraction from soils tend to pull contaminants from particles that would not ordinarily occur in the natural environment.…”

Ecotoxicity Tests for Compost Applications

“…The test is short, only 72 h. The test has been applied in genotoxic studies on waste, contaminated soil, sewage sludge, and sediments Donelly et al, 1991;Kohl et al, 1989;Joutti and Ahtiainen, 1994). Speci"c Salmonella typhimurium strains with an obligatory requirement for histidine are used to test mutagenicity.…”

Open Problems in the Derivation of Soil Quality Criteria from Ecotoxicity Experiments

“…in the light of genetic variation and the ability of organisms to adapt to stress factors, is still an open question (De Raat et al, 1990). The interpretation of test results is complicated by the fact that mutagenic activity is not only detected at contaminated sites but also in unpolluted soil (Kool et al, 1989;Brown et al, 1985) and often bears no clear relationship with the concentration of known mutagens (Donnelly et al, 1991).…”