Microbial Bioremediation of Obsolete Pesticides at Their Disposal Sites, In Situ

In this study, we have developed a bioaugmentation and bioremediation technology that can be used in situ at contaminated sites. A former pesticides store in Chym–Korgon village (N 42049′ 23.9″ and E 75031′ 49.8″) in Kyrgyzstan was determined to be a suitable place for testing the efficacy of the bioremediation technology. The soil around the warehouse was found to be degraded, from over 50 years of exposure to banned pesticides. Chromatographic analyses showed that there were 19 types of obsolete pesticides present in the soil at different concentrations. Three conditions were tested: application of fertile soil and bioproduct, application of fertile soil and no bioproduct (Control 1) and no fertile soil and no bioproduct (Control 2). We used the in situ aerobic bioremediation approach: the treatment was applied directly to the contaminated soil and natural attenuation, bioaugmentation and biostimulation were utilized. For the bioaugmentation, three bacterial species were used such as Stenotrophomonas sp. (Ps-B strain), Lysinibacillus fusiformis (SA-4 strain) and Enterobacter cloacae (SB-2 strain). Our findings demonstrate that the bioproduct developed from the above bacterial species is a highly effective pesticide decomposition tool. In this study, up to 99.0 ± 0.05 (P ≤ 0.05) of pesticides were degraded within six months of the initiation of the bioremediation process.

Keyword: agrochemical improvement of polluted soils; banned pesticides; bioaugmentation; former pesticides store