Estimation of Efficiency of Bio- and Phytoremediation for Pesticides Contaminated Soil

Abstract

Natural recovery of environmental pollution - natural attenuation, - is a long-term process. Development of a bioremediation technology for polluted soil is a multi-step process, which requires the integrated application of several methods: stimulation of the indigenous microflora in the contaminated site, and addition of microorganism-destructors to the soil. Recently at the final stages of soil remediation the method of phytoremediation is actively used. To estimate the efficiency of bioremediation of pesticides contaminated soil, using stimulation of anaerobic or facultative anaerobic microflora and phytoremediation applied afterwards. The soil was collected nearby the former destroyed storehouse of POPs. Pesticide residues in soil were evaluated using GC/MS multiresidue method, and the complex pollution of DDTs and trifluralin was found. With a view to remediate this complex contamination, the polluted soil was treated in combined aerobic and anaerobic conditions during 3.5 months, then the method of phytoremediation was used. The trifluralin content was reduced to 4-6% of the initial amount in all experimental variants as a result of bioremediation in anaerobic/aerobic conditions. Phytoremediation had not significant effect on trifluralin decomposition - only 2-3%. Before phytoremediation DDT was decomposed on 27.5-29.0%. After the phytoremediation, the degradation of pesticide amounted 56.3-72.5%. This study has shown, that in the case of complex pollution, phytoremediation, as a method of supplementary remediation, was important for the decomposition of DDT and DDE, and it was not essential for the mineralization of DDD and trifluralin.