ABSTRACT
Microorganisms isolated from pesticide-contaminated soils using pour-plate method were investigated for their ability to degrade dichlorvos and glyphosate pesticides. The initial concentrations of the insecticides in the parent stock were determined by spectrophotometry. The organisms isolated from the contaminated soils included Bacillus sp, Arthrobacter sp, Klebsiella sp, Chromobacterium sp.; Micrococcus sp. And Staphylococcus sp. The fungi were isolated as Aspergillus niger, Trichoderma sp, Penicillium sp. and Rhizopus sp. Of all the isolates, only Bacillus sp, Proteus sp and Aspergillus sp were able to grow on the media incorporated with the pesticide. The pattern of degradation on the dichlorvos was similar for all the microbial treatments with the percentage degradation ranging from 98.87% to and 99.25%. The effects of the different treatments were significantly different. However, the treatments on glyphosate showed varying degrees of degradation ranging from 21% degradation to 81.92%. There was no significant difference in the degradation after 8 weeks and after 12 weeks for the dichlorvos treatment. The treatments on the glyphosate showed a more efficient degradation after the 12th week than after the 8th week hence prolonged time enhanced the degradability. The tested microbial treatments with the isolates except Proteus sp. showed excellent potential for biodegradation of dichlorvos and glyphosate pesticides hence they may be candidates for biodegradation or removal of these pesticides from the soil |
KEYWORDS: |
Pesticides, dichlorvos, glyphosate, degradation, microorganisms, cassava, soil |
