Preliminary study on the enhanced bioremediation of PAHs- contaminated soil in Beijing and assessment of remediation effect based on toxicity tests

Abstract

Abstract This study focuses on the soil contaminated by polycyclic aromatic hydrocarbons (PAHs) in typical coking polluted sites in Beijing, conducts research on PAHs enhanced bioremediation and evaluation methods of remediation effect based on toxicity testing, and examines the changes of pollutant concentration components in the process of ozone preoxidation coupled biodegradation in the tested soil samples. The toxicity effect of mixed PAHs in soil was directly evaluated using the Ames test, and the correlation between mixed PAHs mutagenicity and BaP toxicity was investigated in an effort to establish a carcinogenic risk assessment model based on biological toxicity test to evaluate the remediation effect of PAHs-contaminated soil. It offers a theoretical and methodological foundation for the evaluation of the bioremediation effect of PAHs-contaminated soil in industrially contaminated sites. The results revealed that the removal rate of PAHs after 5 mins of O3 preoxidation and 4 weeks of soil reaction with saponin surfactants and medium was 83.22 %. After restoration, the soil PAHs extract at a dose of 2000 μg/dish exhibited a positive reaction to the TA98 strain and the carcinogenic risk assessed by the Ames toxicity test was 8.98 times that calculated by conventional carcinogenic PAHs toxicity parameters. The total carcinogenic risk of repaired soil samples was approximately one order of magnitude less than that of original soil samples.