Environmental Exposure Monitoring And Risk Assessment Of New Methylsiloxane Pollutants In The Nanjing Section Of Chuhe Rive

Cyclicvolatile methylsiloxane(cVMSs)has been widely used in industrial production and daily life because of its high thermal stability and low surface tension,and it is a kind of emerging organicpollutants.cVMSs can enter the environment through various channels,and its persistence,toxicity and bioaccumulation in the environment have attracted wide attention.At present,the report about the pollution status and risk assessment of cVMSs in our environment is less.Based on this,the concentration and distribution of three kinds of cVMSs in surface water,sediment,soil and air were analyzed by sampling in Nanjing section of Chuhe River.The ecological risk assessment of cVMSs in surface water,sediment and soil of Chuhe River was carried out by using quotient method.The main research results are as follows:(1)Based on gas chromatography-mass spectrometry(GC-MS)technology,pretreatment and instrumental analysis methods of three kinds of cVMSs in water,sediment,soil and air were established and optimized.These three cVMSs had good linear relationships between chromatographicarea and concentrations within the concentration range of 2～200μg/L,and the correlation coefficients(R~2)were all greater than 0.99.The detection limits of target substances in water,sediment,soil and air samples were 3.30～4.50 ng/L,0.33～0.45μg/kg,1.32～2.68 ng/m~3,respectively.The recoveries ranged from 65.4%to 121.0%.(2)The pollution levels of cVMSs compounds in different environmental media were analyzed.The results showed that:in the surface water samples,the detection rates of D4,D5and D6 were 38.1%,95.2%and 100%,respectively,and the concentration range of total cVMSs at each sampling point was 13.66～77.90 ng/L.In the sediment samples,the detection rates of D4,D5 and D6 were 66.7%,86.7%and 100%,respectively,and the concentration range of total cVMSs at each sampling point was 0.56～49.74μg/kg.In the soil samples,the detection rates of D4,D5 and D6 were 66.7%,20%and 100%,respectively,and the concentration range of total cVMSs at each sampling point was 1.90～7.05μg/kg.In the air samples,the detection rates of D4,D5 and D6 were 100%,100%and 80%,respectively,and the concentration range of total cVMSs at each sampling point was 29.35 ng/m~3～175.10ng/m~3.The mainly cVMSs in water and soil is D6,in sediment is D5,and in air is D4.Compared with the results of other regions at home and abroad,the cVMSs in Nanjing section of Chuhe River was at a medium and low level.Further analysis showed that the concentration of cVMSs in the samples near the Nanjing Jiangbei Chemical Industry Park was significantly higher,while the concentration of cVMSs in the samples far from the Nanjing Jiangbei Chemical Industry Park was significantly lower,indicating that the Nanjing Jiangbei Chemical Industry Park was an important source of cVMSs pollution.In addition,high concentration of cVMSs was found in the samples located near the intersection of the Nanjing section of Chuhe River and the Chuzhou section of Chuhe River.(3)The results of ecological risk assessment of three kinds of cVMSs in surface water,sediment and soil based of Chuhe River on quotient method showed that:in surface water environment,D4 was at a medium/low risk,D5 was at a low risk,D6 was at a medium/high risk;in sediment environment,D4 was at a medium/high risk,D5 and D6 was at a low risk;in soil environment,D4/D5/D6 was at a low risk.