F. Hong et S. Pehkonen, HYDROLYSIS OF PHORATE USING SIMULATED ENVIRONMENTAL-CONDITIONS - RATES, MECHANISMS, AND PRODUCT ANALYSIS, Journal of agricultural and food chemistry, 46(3), 1998, pp. 1192-1199
The hydrolysis of phorate, an organophosphorus pesticide, was studied
under simulated environmental conditions. Several metal oxides (alumin
um hydroxide, hematite, goethite, and ferrihydrite) were chosen to rep
resent; the solid phase in natural aquatic systems. Several degradatio
n products were identified using GC-MS in combination with wet chemist
ry methods. Microtox was used to measure the toxicity of phorate and o
ne of the degradation products, diethyl disulfide. Two potential react
ion pathways were proposed for the alkaline hydrolysis of phorate that
results in unusual products, such as formaldehyde and diethyl disulfi
de. No statistically significant catalytic effect was observed for the
four metal (hydr)oxides used in the study. However, diethyl disulfide
was found to be highly toxic (EC50 is 2.0 ppm) This study again confi
rmed the need for the study of the environmental impact of the degrada
tion products of pesticides.