Effects of multiple environmental factors on the elimination of methomyl in aquaculture water

Abstract

Methomyl is a highly effective broad-spectrum carbamate pesticide that is widely used in the control of pests and diseases in crops. However, few studies have assessed the degradation of methomyl residues in aquaculture environments. In this study, the effects of pH, temperature, illumination, and aerobic/anaerobic conditions in pond water were analyzed to study the degradation pattern of methomyl. The pesticide residues in all treatments were extracted per solid-phase extraction technique and analyzed using liquid chromatography-mass spectrometry. The results showed that the degradation process of methomyl satisfied the first-order kinetics reaction, and the half-life and percent degradation of methomyl ranged from 6.19−49.33 d and 21−97%, respectively. Simultaneous variance analysis indicated that all the tested experimental factors had a significant effect on the results, with pH being the most significant. We conclude that methomyl was used frequently in summer, and that high water temperature and long illumination contribute to the degradation of methomyl. We provide theoretical guidance for the safer use of methomyl in production by further reducing the risk from methomyl residues and further ensuring the safety of products from aquaculture.