Chlorpyrifos – Methyl Degradation in Soil and Human Exposure

Synthetic pesticides are one of the most widespread methods used for pest control in agriculture. Chlor- pyrifos-methyl is commonly used in Romania, and it is classified as an organophosphorus non-carcinogenic substance used to control insects, by inhibiting the activity of acetylcholinesterase. This study's aim was to monitor the degradation of chlorpyrifos-methyl pesticide after spraying directly on vegetation-free soil, under natural conditions, and to calculate the exposure dose through ingestion and dermal contact. The presence of pesticides in the vegetation-free soil was detectable even after 133 days following the time of use. After 49 days, significant chlorpyrifos-methyl concentration differences (p<0.05) had been recorded for the two soil depths (0-5 cm and 30 cm), suggesting a high degree of retention in the soil surface in question. After this period of time, the concentration's trend was to equalize. No significant differences between chlorpyrifos-methyl concentrations collected from 0-5 cm and 30 cm depths had been found after 133 days. The calculated oral and dermal exposure doses, as well as the cumulative dose, were significantly lower than ADI for adults and children.