Study On Environmental Behavior And Health Risk Of Endosulfan In Topsoil Of Gansu And Its Surrounding Areas

Endosulfan is considered to be a persistent organic pollutants,which is characterized by persistent,bioaccumulative,semi-volatile and highly toxic,has the ability of long-range transport behaviors mainly through air and water.Endosulfan in soil may transfer to the air,water,sediment and plants by such as the processes of volatilization,diffusion and migration.As a result,they can easily accumulate in human beings by bioconcentration and biomagnification,and endanger the health of human beings.So it has the great theoretical significance and realistic value for pollution control to know soil pollution levels,understand the transfer and fate behavior and evaluate the health risk of endosulfan in study areas.In this study,32 topsoil samples including urban,rural and background sites were collected in Gansu and its surrounding areas of China.Every isomer residue of endosulfan including a-endosulfan and β-endosulfan of these samples was determinated using Agilent 7890-5975C GC-MSD in order to know the soil pollution levels of endosulfan.In addition,Combining the TaPL3 model and the fugacity model,the long-range transport potential trough air and water and the concentration distribution of endosulfan in every environmental phase were simulated in Lanzhou region.Furthermore,the environmental health risk was evaluated based on the above simulated concentrations in every environmental phase in semi-arid Lanzhou area.The specific study results are as follows:(1)The concentrations between a-endosulfan and β-endosulfan in the soil of urban sites of Gansu and its surrounding areas were obvious variable,the contents of a-endosulfan in the soil of Tianzhu and Baiyin was significantly higher than those of other cities.Meanwhile,the background sites of Hami,Zhangye,Lanzhou showed that there were some new sources of endosulfan were inputted.Furthermore,the Fa-endo values,namely,α-endosulfan/α-endosulfan+β-endosulfan ratios indicated that the degradation of α-endosulfan was stronger than that of P-endosulfan in Jiuquan,Zhangye,Jinchang,Dingxi,Tianshui and Chengxian areas.Comparing with the residues of α-endosulfan and β-endosulfan in other cities of China,the soil pollution levels of endosulfan were at a lower level in Northwest.(2)The long-range transport potential of endosulfan by air and water exhausted into the environment system in Lanzhou area showed that the α-endosulfan andβ-endosulfan had the abilities of long-range transport potential.The characteristic travel distance(CTD)values were 828 and 1317km in atmosphere,9906and 11964km in water,respectively.The soil phase was the main reservoir of endosulfan by the emission of atmosphere,and the water phase and sediment phase were the main reservoir by emission of water.(3)The study results of three multi-media fugacity model showed that sediment phase was the main reservoir of α-endosulfan and β-endosulfan in Lanzhou area,the mass fraction were 99.7%and 99.9%respectively,and in favor of the distribution of atmospheric aerosols and adsorption of sediments in water.The main input sources of endosulfan were air advection inputs and pesticide application,the degradation in sediment and air advection output were the major route to disappear from the study area.(4)For health risk assessment of endosulfan,the study results showed that the values of non-cancer risk for adults and children were less than 1 in Lanzhou region,and it would have no significant non-carcinogenic health effects to local residents.