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Genotoxicity changes in test plot soil: Impact on risk assessment at a contaminated site planning bioremediation

Conference ·
OSTI ID:462553
;  [1]
  1. Texas A and M Univ., College Station, TX (United States)
Soil samples from test plots designed to investigate the suitability of biodegradation to reduce levels of polycyclic aromatic hydrocarbons (PAHs) and pentachlorophenol (PCP) were collected and solvent-extracted throughout a four-month study. Samples were followed for contaminant concentration and genotoxicity. Test plots were constructed to represent four concentrations of contaminated soil. Although the highest PCP concentration plot was negative in the Salmonella/microsome plate incorporation both with and without metabolic activation at the beginning of the treatment period, these soils became cytotoxic by the end of the study when tested without metabolic activation, and chemical analysis indicated no degradation of PCP. The methanol extract from the lowest PCP concentration plot was positive in the plate incorporation assay at the beginning of the study with an average weighted activity of 29 revertants/gram soil without and 32 revertants/g with metabolic activation at the highest dose level. The mutagenic potential of the methanol extract of this soil increased to an average weighted activity of 306 revertants/g without and 291 revertants/g with metabolic activation, despite a reduction from 46 to below 10 {micro}g PCP/g soil. A human health risk assessment employing the current US/EPA method of incorporating chemical concentration data in calculating cancer risk was then compared with the level of risk that can be inferred from the corresponding bioassay data. These findings emphasize the need for careful remediation design as this step will prove critical in achieving both maximum biodegradation and protection of human health.
OSTI ID:
462553
Report Number(s):
CONF-961149--
Country of Publication:
United States
Language:
English