戊唑醇在环境中的降解迁移和生物富集性研究

戊唑醇属于内吸性三唑类杀菌农药,在国内广泛用于田间病虫防治,故其在环境中的归趋备受关注。采用室内模拟试验方法,研究了戊唑醇在水-沉积物中的降解特性、土壤中的吸附性和在斑马鱼中的生物富集性。结果表明:好氧条件下,戊唑醇在河流与湖泊水-沉积物系统中农药总量的降解半衰期分别为533.2、433.2 d;厌氧条件下,河流与湖泊水-沉积物系统中降解半衰期分别为364.8、1 732.9 d;沉积物系统降解半衰期较长,降解速率主要受水中戊唑醇的降解速率影响。戊唑醇在江西红壤、太湖水稻土、常熟乌杉土、东北黑土中的吸附性符合Freundlich方程,Kd值分别为7.4、11.8、11.2和15;吸附性大小次序为东北黑土太湖水稻土常熟乌杉土江西红壤;以有机碳含量表示的土壤吸附常数KOC在698.9~1 635.5之间;影响戊唑醇土壤吸附性的主要因素为土壤有机质含量和p H。戊唑醇在斑马鱼中的生物富集系数BCF8 d为21.52~25.30,具有中等富集性。戊唑醇在水体环境中具有较强稳定性,不易被土壤吸附,且具有一定的生物富集性,可能会对水体和水体生物造成一定的污染。

Degradation, Migration and Bioaccumulation of Tebuconazole in the Environment

Tebuconazole is a systemic triazole fungicide, which was applied to control pests in the fields frequently in China, so increased concern focused on the environmental behavior of this kind of pesticide. In this study, we in-vestigated the degradation of tebuconazole in water-sediments and its bioconcentration in zebrafish by simulation test in laboratory systematically. The result showed that the half-times of tebuconazole in water-sediment system were 533.2 d (river system) and 433.2 d (lake system) under aerobic conditions, while these were 364.8 d (river system) and 1732.9 d (lake system) under anaerobic conditions, indicating that the degradation rate was slow in both lake system and river system. In the water-sediment system, the effect of degradation rate is mainly dependent on the degradation in water. Adsorption results showed that the adsorption of tebuconazole on tested soils fits well with Freundlich model, and the adsorption coefficient (Kd ) was 7.4 in Jiangxi red soil, 11.8 in Taihu paddy soil, 11.2 in Changshu wushan soil, and 15 in Northeast black soil, respectively. The adsorption capacity ranked as Northeast black soil>Taihu paddy soil>Changshu wushan soil>Jiangxi red soil. The adsorption of tebuconazole on soil was primarily related to the organic carbon and pH of soils. The bioconcentration factors (BCF, 8 d) of tebu-conazole in Brachydanio rerio were between 21.5 and 25.3, showing that tebuconazole was classified as medium bioconcentration pesticide. Due to the fact that tebuconazole has long-term retention in sediment and showed medi-um bioconcentration, tebuconazole may cause pollution in water body and affect aquatic organism.