Persistence of chlorpyrifos and endosulfan in soil

The effect of different factors, such as temperature and soil moisture content, in the degradation of chlorpyrifos and endosulfan in soil was studied under laboratory conditions. In addition, field experiments were conducted in the Spanish region of Badajoz to determine the levels of chlorpyrifos and endosuffan throughout the growing season and the residual levels of these chemicals after harvest of tomato. In general, an increase of the pesticide degradation rate with temperature was observed while correlation of the degradation rate with the soil moisture content was only observed for chlorpyrifos and alpha-endosulfan. The presence of rhizosphere soils did not change the pesticide degradation rate under the conditions assayed.