基于旱地土壤环境风险的农药毒死蜱的施用限值研究

Research on the application limit of chlorpyrifos based on soil environmental risks in drylands

通过开展田间试验,研究毒死蜱在玉米、小麦和大豆3种作物田土壤中的降解及环境风险,基于毒死蜱及其降解产物TCP的残留特征和环境风险,计算毒死蜱施用限值.研究表明玉米田土壤中的毒死蜱残留量大于大豆田和小麦田;毒死蜱在农田土壤中的降解速率随着施用浓度的增加而提高.小麦、大豆、玉米3种作物种植土壤中毒死蜱及TCP的短期和长期生态风险均有差异.玉米、大豆和小麦3种作物农田中,当超过推荐剂量施用毒死蜱,毒死蜱及TCP均具有较高短期风险和长期生态风险,相对于毒死蜱,TCP对土壤的生态风险更高.基于旱地土壤的毒死蜱及TCP的环境风险,通过模型计算农药毒死蜱在大豆田中的施用限值为0.4412 kg·hm^(-2),在小麦田中的施用限值为0.5034 kg·hm^(-2),在玉米田中的施用限值为0.5487 kg·hm^(-2).

Field trials were carried out to study the degradation and environmental risks of chlorpyrifos in corn, wheat and soybean soils. Based on the residual characteristic and environmental risk of chlorpyrifos and its degradation product TCP(3,5,6-trichloro-2-pyridylphenol), the application limit of chlorpyrifos was calculated. The results showed that residual concentration of chlorpyrifos in corn soils were higher than those in soybean and wheat soils, and the degradation rate of chlorpyrifos in soils increased with the increasing application concentration. The short-term and long-term ecological risks of chlorpyrifos and TCP in wheat, soybean and maize were different. In corn, soybean and wheat fields, the excessive applications of chlorpyrifos caused higher short-term and long-term ecological risk. Compared with chlorpyrifos, TCP has higher ecological risk to soil. Based on the environmental risk of chlorpyrifos and TCP in dry land soil, the application limit amount of Chlorpyrifos in soybean, wheat, and corn field were 0.4412, 0.5034, 0.5487 kg·hm^(-2), respectively.