Evaluating the Effects of Bioremediation on Genotoxicity of Polycyclic Aromatic Hydrocarbon-Contaminated Soil Using Genetically Engineered, Higher Eukaryotic Cell Lines

Abstract

Bioremediation is one of the commonly applied remediation strategies at sites contaminated with polycyclic aromatic hydrocarbons (PAHs). However, remediation goals are typically based on removal of the target contaminants rather than on broader measures related to health risks. We investigated changes in the toxicity and genotoxicity of PAH-contaminated soil from a former manufactured-gas plant site before and after two simulated bioremediation processes: a sequencing batch bioreactor system and a continuous-flow column system. Toxicity and genotoxicity of the residues from solvent extracts of the soil were determined by the chicken DT40 B-lymphocyte isogenic cell line and its DNA-repair-deficient mutants. Although both bioremediation processes significantly removed PAHs from the contaminated soil (bioreactor 69% removal; column 84% removal), bioreactor treatment resulted in an increase in toxicity and genotoxicity over the course of a treatment cycle, whereas long-term column treatment resulted in a decrease in toxicity and genotoxicity. However, when screening with a battery of DT40 mutants for genotoxicity profiling, we found that column treatment induced DNA damage types that were not observed in untreated soil. Toxicity and genotoxicity bioassays can supplement chemical analysis-based risk assessment for contaminated soil when evaluating the efficacy of bioremediation.

Screening Nonionic Surfactants for Enhanced Biodegradation of Polycyclic Aromatic Hydrocarbons Remaining in Soil After Conventional Biological Treatment

“…26, 27 The soil was treated in a continuously stirred, semi-continuous, slurry-phase (15% w/w) laboratory-scale aerobic bioreactor. Every seven days, 20% of the treated slurry was replaced with a slurry of untreated (feed) soil in a pH 7.5 buffer containing 5-mM phosphate and 2.5-mM ammonium nitrate.…”

Biosurfactant-enhanced bioremediation of aged polycyclic aromatic hydrocarbons (PAHs) in creosote contaminated soil

“…Polycyclic aromatic hydrocarbons (PAHs) are of human health concern due to their known or suspected genotoxic, mutagenic or carcinogenic effects (Hu et al, 2012). PAHs are mainly derived from anthropogenic activities, such as biomass burning, incomplete fossil fuel combustion, oil spills and some industrial processes .…”

In-Situ Remediation Approaches for the Management of Contaminated Sites: A Comprehensive Overview

“…Weyens et al ( 2013 ) achieved increased accumulation of Cd and toluene by inoculating the willow tree with Cd-resistant, and siderophore-and IAA-producing engineered Burkholderia vietnamiensis BU61 as a donor of the pTOM-TCE plasmid. Hu et al ( 2012 ) reported 84 % PAH removal by the use of genetically engineered higher eukaryotic lines. Sood et al ( 2010 ) developed novel yeast ( Candida digboiensis ) strain that could remove 72 % heneicosane in 8 days at pH 3.0, and 40 mg of eicosane in 50 ml minimal salts medium in 10 days.…”