Study On The Fate Behavior Of Perfluoroalkyl Compounds In Dalian Based On Fugacity Model

At present,PFASs as emerging persistent organic pollutants,are ubiquitous in the environment,biota and humans.Therefore,mastering the transfer and fate of PFASs among environmental media plays an important role in carrying out its environmental risk assessment.The multimedia environmental fugacity model is widely used in the simulation and prediction of pollutant behavior because of its simple operation and great simulation result.In this paper,the fugacity fraction model was established.Based on concentrations of PFASs in seawater and sediment samples from the Dalian bay,the diffusion trend of PFASs at the sediment-water interface and the spatial variability of PFASs were investigated by using the fugacity fraction(ff)and the coefficient of variation(Cv),respectively.Furthermore,the effect of organic carbon content on the diffusion trend was analyzed with the response coefficient(RC);A level ? multimedia fugacity model was constructed to investigate the distribution and fate of PFOS in environmental multimedia of Dalian;A level IV multimedia fugacity model was constructed to simulate and predict the dynamic distribution and fate of PFOS in the environmental multimedia from 1980 to 2030 in Dalian.The specific conclusions are as follows:(1)The total concentration of 9 PFASs in seawater and sediments of Dalian Bay is moderately variable.The variation of concentration in the sediment was slightly larger.During the diffusion process at the sediment-water interface,the perfluoroalkyl sulfonic acids and perfluoroalkyl carboxylic acids exhibited the similar diffusion characteristics that was the ff value gradually decreased with increasing chain length of PFASs.Short-chain PFASs tended to exist in seawater,while the long-chain PFASs tended to diffuse into sediments.The organic carbon content is an important parameter affecting the diffusion trend of PFASs at the sediment-water interface,and the effect on long-chain PFASs was more obvious than that on short-chain PFASs.As a kind of persistent organic pollutant,PFOS is mainly in equilibrium at present in the Dalian bay.(2)The simulated concentrations of PFOS in atmosphere,water,soil and sediment were consistent with the measured values.The main transfer routes of PFOS between media were from atmosphere to soil and from soil to water.Meanwhile,water and soil were identified to be main sinks of PFOS in Dalian area.The primary sources of PFOS in the area were the advection inputs in atmosphere and water,and the advection output of PFOS in atmosphere was the primary outlet from Dalian.Sensitivity analysis showed that the main parameters affecting the model output were the organic carbon partition coefficient,solubility,advection inputs in atmosphere and water,and the runoff velocity of water in soil and temperature.The results of uncertain analysis indicated that the change of the overall parameters had greatest impact on the result in water and least impact on that in sediment.(3)The level ? multimedia fugacity model is more suitable for predicting the dynamic trend of PFOS in Dalian.With the change of time,the transfer of PFOS in the environmental media mainly changes from atmosphere to soil to soil to water.Sensitivity analysis results show that the input parameters of emission rate of atmosphere,water and soil,the precipitation rate,the runoff velocity of water in soil,vapor pressure and solubility greatly affect the output of the model,of which the runoff velocity of water in soil changes significantly with time.