Mycoremediation of Dichlorvos Pesticide Contaminated Soil by Pleurotus pulmonarius (Fries) Quelet

The extensive use of pesticides leads to accumulation of a huge amount of residues in the environment. As such, the present study investigates the potentiality of Pleurotus pulmonarius to bioremediate dichlorvos pesticides (2,2-dichlorovinyldimethylphosphate) in contaminated soil. DDVP-polluted soils have been contaminated in five concentrations (5% v/w, 10% v/w, 15% v/w, 20% v/w, and 25% v/w), and the soil samples have been inoculated and incubated with pure culture of growing spawns of P. pulmonarius, obtained from commercial mushroom laboratory of Federal Institute of Industrial Research Oshodi, Lagos. The control, however, has not been inoculated. Each treatment has been in triplicates with the soils, analyzed for total amount of DDVP at day 0 and day 60, using gas chromatography and mass spectrometry. Also, pH, moisture content, and total organic matter of the soil have been determined. Results show that the rate of DDVP degradation in the soils with Pleurotus pulmonarius has been higher than the soil samples without mushroom after 60 days. However, for the control without mushroom (loss due to natural attenuation) and those inoculated with P. pulmonarius (bioremediation) the loss percentage of DDVP ascended with the percentage of pesticide from 5% to 25%. The DDVP loss across all different concentrations of mushroom inoculation have been significant (p<0.05); however, for natural attenuation, it has not been significant (p>0.05), except for the lowest pesticide level (5%). Activities of mycelia have decreased soil pH, moisture content, and total organic matter. There has been a very minimal pesticide bioaccumulation in mushroom tissue, which has not been significant (p>0.05), but considerable at p<0.001, indicating that P. pulmonarius has the potential to degrade DDVP pesticides in soil.