In situ microbial bioremediation of obsolete pesticides at their disposal sites

Abstract

Soil pollution by pesticides is a global problem in many countries, including Kyrgyzstan. Currently, 50 storage facilities for obsolete banned pesticides exist, severely threatening the surrounding populations and environment. In this study, in situ bioremediation technology was used to remove pesticide contamination from soil around the storage facilities. Three conditions were tested: application of fertile soil and bioproduct, application of fertile soil and no bioproduct (Control 1), and application of fertile soil and no bioproduct (Control 2). An aerobic bioremediation approach was used: the treatment was applied directly to the contaminated soil. For the bioaugmentation, three selected active degrading bacterial species were used: Stenotrophomonas sp. (Ps-B strain), L. fusiformis (SA-4 strain) and E. cloacae (SB-2 strain). Regular aeration, loosening and watering were performed during the subsequent months to create the conditions required to activate the local microflora and the degrading activity of the bacterial species in the bioproduct. The bioproduct of three active bacteria species has demonstrated a high pesticide decomposition effect. The pesticides were degraded from 85.6 to 99.0 ± 0.05% within six months of initiating the bioremediation process. The efficiency of the degradation process depended on optimum atmospheric conditions, that is, temperature, pH, and moisture content of the soil. Our study recommends using the agrotechnical and biotechnological approach for moderately pesticide-polluted soils and pesticide storage areas.

Keywords:

• Aerobic active degradative bacteria
• agrochemical improvement of polluted soils
• bioaugmentation and bioremediation technology in situ
• obsolete pesticides

Author contributions

All authors contributed to the study’s conception and design. Material preparation, data collection and analysis were performed by [Maxabat Konurbaeva], [Saykal Bobusheva] and [Tinatin Doolotkeldieva]. Tinatin Doolotkeldieva wrote the manuscript’s first draft and final version, and all authors commented on previous versions. All authors read and approved the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by [Technical Assistance in Implementation of Trails on Bioremediation of PDPs Contaminated Soils Project] (Grant numbers [GCP/SEC/011/GFF]. Author Tinatin Doolotkeldieva has received research support from The Food and Agriculture Organization of the United Nations, FAO.