Fate and transport of ethoprophos in the Jamaican environment

The hydrolytic half lives of ethoprophos in distilled, river, brackish and open sea water were 25, 133, 65 and 81 days, respectively. Under laboratory conditions, volatilisation of the residues after 12 h was 1.4]3.6, 2.3]4.5 and 6.5]20.2% from a sandy loam soil with 1, 10 and 20% moisture levels, respectively. Photolysis in soil was significantly faster P-0.05. in direct sunlight T1r2 of 4.7 days. than in the shade T1r2 of 12.3 days.. The microbial degradation of ethoprophos was more than two-fold faster in unsterile soil T1r2 of 10.9 days. than in sterile soil T1r2 of 28.8 days.. The runoff of ethoprophos from unweeded plantation soil at 238 slope was significantly Ps0.015. less than at 388 slope; the amounts lost after 9 weeks and 27.5 mm of rainfall were 89.4 and 91.2%, respectively, of the applied amount from the two respective slopes. In the weeded plots, 93.6 and 92.4% of the applied insecticide were lost from 238 and 388 slopes, respectively. Under laboratory conditions, between 67.0 and 85.1% of ethoprophos leached through the soil columns. Under field conditions, after 9 weeks and 25 mm of rainfall, only 2.8 and 2.0% residues were recovered at a depth of 10]15 cm from unweeded and weeded slopes, respectively at 238 slope, and 2.2 and 1.9% from the two respective plots at 388 slope.