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Oxidative mutagenicity of polar fractions from polycyclic aromatic hydrocarbon–contaminated soils
Author(s) -
Park Joanna,
Ball Louise M.,
Richardson Stephen D.,
Zhu HongBo,
Aitken Michael D.
Publication year - 2008
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/07-572.1
Subject(s) - genotoxicity , chemistry , catalase , environmental chemistry , ames test , oxidative stress , bioassay , carcinogen , mutagen , reactive oxygen species , toxicity , hydrogen peroxide , polycyclic aromatic hydrocarbon , pentachlorophenol , biochemistry , reversion , bacteria , organic chemistry , biology , salmonella , genetics , gene , phenotype
Soils at hazardous waste sites contain complex mixtures of chemicals and often are difficult to characterize in terms of risk to human and ecological health. Over time, biogeochemical processes can decrease the apparent concentrations of pollutants but also can lead to accumulation of new products for which toxicity and behavior in the environment are largely unknown. A bioassay‐directed fractionation technique was used to assess the contribution of redox‐active bacterial metabolites to the toxicity of soil contaminated with polycyclic aromatic hydrocarbons (PAHs). A reverse mutation assay with Escherichia coli WP2 uvrA /pKM101 (IC188) and E. coli WP2 uvrA oxyR /pKM101 (IC203) was used to screen fractions for genotoxicity. Strain IC203 carries the Δ oxyR30 mutation, which prevents the expression of antioxidant proteins in response to oxidative stress and increases its reversion by compounds that generate reactive oxygen species (ROS). Polar fractions of PAH‐contaminated soil extracts were mutagenic to strain IC203 but not to strain IC188, suggesting the involvement of ROS in genotoxicity. Genotoxic potencies ranged from 300 to 1,700 revertants per milligram of fraction. Catalase was able to decrease IC203 reversion, implicating the involvement of hydrogen peroxide as a key ROS. Oxidized PAH compounds, including quinones, were identified in the mutagenic fractions but were not by themselves mutagenic. Deasphalted whole extracts and recombined fractions were not mutagenic, indicating that interactions between compounds in different fractions can mitigate genotoxicity.