Degradation of monocrotophos in soils.
The degradation of a widely used organophosphorus insecticide, monocrotophos (dimethyl (E)-1-methyl-2-methylcarbamoyl vinyl phosphate) in two Indian agricultural soils at two concentration levels, 10 and 100 microg g(-1) soil under aerobic conditions at 60% water-holding capacity at 28+/-4 degrees C was studied in a laboratory. The degradation of monocrotophos at both concentrations in black vertisol and red alfinsol soils was rapid accounting for 96-98% of the applied quantity and followed the first-order kinetics with rate constants (k) of 0.0753 and 0.0606 day(-1) and half-lives (t1/2) of 9.2 and 11.4 days, respectively. Degradation of monocrotophos in soils proceeded by hydrolysis with formation of N-methylacetoacetamide. Even three additions of monocrotophos at 10 microg g(-1) soil did not result in its enhanced degradation. However, there was cumulative accumulation of N-methylacetoacetamide in soils pretreated with monocrotophos to the tune of 7-15 microg g(-1) soil. Both biotic and abiotic factors were involved in degradation of monocrotophos in soils.
Department of Microbiology, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh, India. vijay_gundi@yahoo.com
Vijay A K B
VA
Gundi
B R
BR
Reddy
D000383:Agriculture; D001673:Biodegradation, Environmental; D004787:Environmental Pollution / Q000032:analysis*; D007194:India; D007700:Kinetics; D008999:Monocrotophos / Q000032:analysis*; D012987:Soil / Q000032:analysis* / Q000592:standards; D012989:Soil Pollutants / Q000032:analysis*
D012987:Soil; D012989:Soil Pollutants; D008999:Monocrotophos