Multimedia Environment Modeling Of Polycyclic Aromatic Hydrocarbons In Wetland And Ecological Risk Analysis

A dynamic multimedia environmental mass balance fugacity model was developed and applied to assess the fate and transport of several Polycyclic Aromatic Hydrocarbons(PAHs) in Zhalong Wetland.The current dynamic fugacity model has been applied to assess the fate and transport of the five PAHs in Zhalong Wetland during ten years.The results show that the fugacity and concentrations curves of PAHs are raising periodically per year when dynamic parameters are introduced.The concentrations of PAHs in water,vegetation,fish and Grus japonensis eggs are in turn increasing 87.3%, 89.2%,50.0%and 59.0%.The backgound concentration or initial values of PAHs in soil and air compartments are unknown.These values are roughly estimated by Levelâ…¢model at the condition of the fictitious pollution source.The model validation showed that the differences between predicted and measured concentration of most PAHs are less than 1 log-unit which is in accordance with the model precision.The accumulation and transfer fluxes of envioronmental cells showed that The proportion of PAHs in air,water,soil,sediment,vegetation,Grus japonensis eggs and fish are in turns 0.003%,0.214%,87.55%,12.11%,0.103%,0.009%and 0.004%.It is obvious that soil and sediment are the most important sinks,which accumulated 99.7%of the total PAHs;The accumulation and transfer fluxes are also increasing per year;The exterior import and main export of environmental system are advective input and output of air and water.The model validation shows that the differences between predicted and measured concentration of most PAHs in air are 0.1 log-unit and that of which in soil are 0.5 log-unit.The ecological risk assessment on current situation of Zhalong wetland showed that,although there not exsit seriously PAHs ecological risk in Zhalong wetland at present,but the concentrations of PAHs now still have great potential hazard to living organisms.The calculation result by this model showed that the content of PAHs in each phase will increase year by year.At the end of simulation, for enrichment of food-chain,though the amount of PAHs did not exceed all the ecological risk evalution standards,it could also make seriously toxicity to the whole food-chain.The environmental biology in Zhalong wetland will in high risk influence by PAHs.