Photodegradation of endosulfan and pendimethalin in sunlight

The potential of sunlight photolysis in remediation of pesticide-polluted soils in Sudan is reported. The common pollutants endosulfan (alpha-and beta-isomers) and pendimethalin were exposed to sunlight over glass and soil surfaces and the periodically drawn samples were analyzed by GC-ECD and GC-MS. Photo-degradation followed biphasic model. The half-lives of direct photolysis of the two pesticides over glass and soil surfaces ranged between 1.840-6.720 d and 2.711 to 9.760 d respectively. The respective values for indirect photolysis of the two pesticides with β-carotene over glass surface were 0.846-1.605 d and for benzophenone 1.050-1.626 d. Values for soil β-carotene sensitized photolysis of the two pesticides were 2.260-3.158 d while the corresponding values for benzophenone sensitized photolysis on soil were 1.193-2.880 d. Meteorological factors did not show significant impact on photolysis rates. Despite the significant decrease in starting material in direct photolysis, no photoproducts were detected. However, many photoproducts were detected on the indirect sets. Photo-degradation efficiency can be arranged in the order benzophenone > β-carotene > direct exposure.