The effects of fenitrothion emulsion (organic phosphorous pesticide) and its degraded solution on mice

Experiments were carried out to examine the effects of degradation products on mice. Fenitrothion (MEP) emulsion, a kind of an organic phosphorous insecticide, adjusted to pH 8, pH 10, and pH 14 were degraded by exposure to natural sunlight. Physiological saline, an untreated MEP emulsion, and the three degraded solutions were prepared as experimental chemicals and were administered subcutaneously at a dosage of 0.1 ml/10 g body weight (BW) into the backs of pregnant mice once a day, from the 3rd to the 15th fetal day. Each dose included 20, 40, or 90 mg/kgBW of MEP and several degradation products of MEP. LD50 was determined according to Behrens' method. The mean fetal body weights of 18th day of pregnancy in 40 and 90 mg/kgBW of MEP of the pH 8 degraded solution were 1.09 and 1.16 g, respectively, significantly lower than that of untreated MEP emulsion (1.27 g). Further, LD50 values of the three kinds of degraded solutions were 60-120 mg/kgBW, much lower than that of the untreated MEP emulsion (410 mg/kgBW). These results indicate that the degradation products of MEP emulsion degraded by the exposure of sunlight have an influence on both adult and fetal mice.