Sorption, and Degradation of Prothioconazole and its Metabolites in Soils and Water Sediments and Combinative Toxicity to Gobiocypris Rarus

In order to reduce the burden to the environment, the application of prothioconazole and its metabolites need comprehensive evaluation. Therefore, the environmental behaviors tests of prothioconazole were conducted in different conditions, three typical soils and two types of water-sediment systems under aerobic and anaerobic conditions for degradation, sorption in three types of soil, and individual toxicity of aquatic organism and joint acute toxicity of rare minnow (Gobiocypris rarus) were investigated in present study for first time. Within aerobic and anaerobic situations, half-lives of prothioconazole in soils were in range of 0.0565 to 2.27 days and 0.138 to 1.73 days, respectively. Significant differences (p<0.001) in prothioconazole degradation among three soil types and under different environmental condition were observed. For aerobic situations, half-lives of prothioconazole in the Hunan paddy area and Beijing Qidu reservoir samples were 2.18 and 1.58 days, respectively. In soil and water-sediment, prothioconazole degraded to M01 and M04, and the formation rate of M04 was higher than M01 under aerobic condition. M04 and M01 gradually increased peak in soil and water-sediment system then decreased with time, while prothioconazole decreased gradually. The half-lives of metabolites in soils were higher than parent compound, which was in range of 16.6 and 99.6 days for M01, 15.8 and 50.7 days for M04 under aerobic condition. While, the adsorption capacity (Kf values) of M04 and M01 ranges from 2.09 to 88.92 and 8.98 to 243.30 (μg/g)/(mg/L) in the three soils, respectively. Regarding aquatic toxicity, metabolites did not show higher toxicity than parent, except M01 to Gobiocypris rarus. Acute toxicity assays showed that mixtures of prothioconazole with metabolites exhibited higher toxicity than any compound individually, and indicated interact synergistically at equitoxic ratios and equivalent concentrations. This study provides a comprehensive investigation on the fate and risk posed by prothioconazole in environmental for better human health