| Environmental pollution caused by organophosphorus pesticides and 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 pollutants in target environment.In the present study,fugacity based multimedia fate model combining species sensitivities model?SSD?were employed with dichlorvos and permethrin as model compounds to predict the concentration distribution,transfer fluxes and ecological risks under nonequilibrium steady-state condition.The effect of input parameters on the outputs were evaluated by sensitive and uncertainty analysis.Furthermore,SSD model of aquatic organisms was constructed for dichlorvos and permethrin to assess the potential ecological risk and to determine the maximum annual input amount of dichlorvos and permethrin for the purpose of protecting 95% of species.Results show the predicted concentration of dichlorvos in air,water and sediment were 5.39×10-13,1.56×10-8,9.76×10-11mol·m-3,and the predicted concentration of permethrin in air,water and sediment were 3.99×10-16,5.63×10-11,1.95×10-5 mol·m-3.Most dichlorvos and permethrin were mainly transported from water to air via volatilization,but the dichlorvos output through absorption and the permethrin elimination from air was mostly by particle dry deposition.Dichlorvos output by advection and diffusion,but permethrin was removed by deposition of suspended particulate matter and diffusion.Both of them in water were predominately from advection.Sediment associated dichlorvos input and output process mainly through diffusion.However,permethrin was generally derived from suspended particulate matter deposition,and was eliminated by resuspension and sediment burial.In addition,the results of SSD model suggest HC5 value of dichlorvos and permethrinwas at 3.46 and 2.20×10-2 ng·L-1,respectively.It was much higher than the predicted environmental concentration of dichlorvos and permethrin in water.In order to protect 95% of species in Chaohu Lake,the maximum annual input amount of dichlorvos and permethrin should be controlled less than 2.75 and 943 t·a-1. |
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