模拟巢湖流域氯菊酯的迁移转化和生态风险

近年来,随着大量使用拟除虫菊酯类杀虫剂,导致的环境问题已得到广泛关注.为认识巢湖流域氯菊酯在环境中的赋存状态、迁移转化、环境归趋和生态风险,本研究结合多介质归趋模型和物种敏感性分布模型(SSD),模拟了稳态假设下氯菊酯在巢湖生态系统各环境介质中的浓度分布、迁移通量和去除途径,并通过灵敏性分析和不确定性分析对各输入参数进行了评价.进一步构建污染物的SSD模型,评价了氯菊酯在稳态条件下的潜在生态风险,预测了保护系统中95%的物种时允许最大年输入量.结果表明,氯菊酯在大气相、水体相、沉积物相中的浓度分别为3.99×10~(-16)、5.63×10~(-11)和1.95×10~(-5)mol·m~(-3),沉积物是氯菊酯的最大储库;大气中的氯菊酯主要以挥发形式进入,通过空气颗粒物干沉降消减;水体中的氯菊酯主要以平流输入为主进入,通过底泥沉降消减;沉积物中的氯菊酯主要以底泥沉降形式进入,通过底泥再悬浮和掩埋消减.此外,SSD模型预测的HC5浓度为0.97 ng·L~(-1),假设稳态下预测的水体浓度远低于该值,仅对巢湖流域0.77%的物种产生影响,当年输入量低于78.2 t的情况下,巢湖水体中95%的物种不会受到氯菊酯的威胁.

Modeling the Environmental Behaviors and Ecological Risks of Permethrin in Chaohu Lake

Environmental pollution caused by synthetic pyrethroid insecticides has received a great deal of attention with the increase in usage recently.To understand the occurrence, environmental processes, fate and ecological impact of permethrin in Chaohu Lake, fugacity based multimedia fate model combining species sensitivities model (SSD) were employed.The concentration distribution, and transfer fluxes were predicted under nonequilibrium steady-state condition, and the effect of input parameter on the outputs was evaluated by sensitive and uncertainty analysis.Furthermore, SSD model of aquatic organisms was constructed for permethrin to assess the potential ecological risk and to determine the maximum annual input amount of permethrin for the purpose of protecting 95% of species.The results showed that the predicted concentrations of permethrin in air, water and sediment were 3.99×10^-16, 5.63×10^-11, 1.95×10^-5mol·m^-3, and sediment was the largest sink.Most permethrin was transported from water to air via volatilization, but elimination from air was mostly by particle dry deposition.Permethrin in water was predominately from advection, and was removed by deposition of suspended particulate matter.Sediment associated permethrin was generally derived from suspended particulate matter deposition, and was eliminated by resuspension and sediment burial.The results of SSD model suggested HC₅ value was at 0.97 ng·L^-1, which was much higher than the predicted environmental concentration of permethrin in water.Only 0.77% of species was possibly impacted by exposure to permethrin.In order to protect 95% of species in Chaohu Lake, the maximum annual input amount of permethrin should be controlled below 78.2 t·a^-1.