Abstract

LARA-MORENO, Alba et al. Remediation of a chlorpyrifos contaminated soil using novel bacterial strains and cyclodextrin: evaluation of its effectiveness by ecotoxicity studies. Rev. de Ciências Agrárias [online]. 2022, vol.45, n.4, pp.1031-1040.  Epub Dec 01, 2022. ISSN 0871-018X.  https://doi.org/10.19084/rca.28746.

Chlorpyrifos (CLP) is one of the most widely used insecticides in the world. However, it is highly toxic for living organisms and persistent in the environment. Biological treatment is considered as a good option to remediate polluted environmental areas. Two bacterial strains, Bacillus megaterium CCLP1 and Bacillus safensis CCLP2 were isolated from two selected agricultural soils (R and LL), using enrichment technique in presence of CLP as only carbon and energy source. These strains were able to remove in solution up to 99.1 and 98.9% of CLP after 60 d (initial concentration: 10 mg L-1). Several treatments were performed in a soil artificially contaminated with CLP to enhance its remediation: 1. biostimulation, adding micro- and macronutrients; 2. bioaugmentation, inoculating B. megaterium CCLP1 or B. safensis CCLP2; 3. Addition of randomly methylated β-cyclodextrin (RAMEB), as bioavailability enhancement; 4. bioaugmentation + RAMEB. The best CLP biodegradation results were achieved when bioaugmentation and RAMEB were jointly applied. After biodegradation treatment, an ecotoxicological test was carried out to verify the effectiveness of the bioremediation strategy in soil. Results pointed out that bacteria individually inoculated into the soil were able to decrease the toxicity to undetectable levels.

Keywords : Chlorpyrifos; bioremediation; soil; Bacillus; cyclodextrin.

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