[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.