ENIVRONMENT ASIA

Volume 11, No. 03, Month SEPTEMBER, Year 2018, Pages 133 - 147

Vermiremediation of pesticide contaminated soil using eudrilus euginae and lumbricus terrestris

NJOKU, Kelechi Longinus, OGWARA, Chigoze Alexandria, ADESUYI, Adeola Alex, and AKINOLA, Modupe Olatunde

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We employed vermiremediation technique in this pilot study to bioremediate dichlorvos pesticide (2, 2-dichlorovinyldimethylphosphate) contaminated soil using Lumbricus terrestris and Eudrilus euginae. The contaminated soils were analysed for DDVP contents at initial day and final day in three concentrations of 10% v/w, 20% v/w and 30% v/w using gas chromatography and mass spectrometry technique. Soil pH, moisture content and total organic matter content were also determined. The initial and the final levels of DDVP in the soil samples increased with increase in the amount of pesticide added to the soil. The activities of the earthworms resulted in decrease in pesticide level, pH, moisture content and total organic matter content. The treatment with E. euginae had the highest reduction of pesticide with 66.44% for 10% pesticide contamination, 72.11% for 20% contamination, and 78.34% for 30% followed by the treatment with the combination of both species with 60.12% for 10%, 66.73% for 20% and 71.96% for 30%, and the least degradation by the treatment with L. terrestris 52.96% for 10%, 55.82% for 20%, and 53.91% for 30% DDVP contamination. The reduction across the different concentrations of pesticide for L. terrestris, E. euginae and the combination of both earthworms treated soils were all significant (p<0.05). The initial and the final pH levels were not statistically different (p>0.05) and there was no significant difference in the moisture content of the control against the treatments (p>0.05) but significant at the 20 and 30% DDVP contaminated soil treated with E. euginae only. There was significant difference between the initial and the organic matter contents (p<0.05) for the all concentrations treated with E. euginae and in the combination of both L. terrestris and E. euginae. The results suggest that E. euginae has greater ability to remediate DDVP than L. terrestris while combining L. terrestris with E. euginae can help to improve their ability to remediate soils contaminated with DDVP.

Keywords

Vermiremediation; Pesticide; Earthworm; E. euginae; L. terrestris; Dichlorvos; DDVP

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