Pollution Level and Ecological Risk Assessment of Cyclic Volatile Methylsiloxanes in the Environmental Media in Nanjing Section of Chuhe River

Cyclic volatile methylsiloxane (cVMSs) has attracted extensive attention due to its potential ecological risks after entering the environment. In this study, the samples were collected to analyze concentrations of octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) in the surface water, sediment and surrounding soil of Nanjing section of Chuhe River, and their ecological risks were evaluated. The results show that the detection rates of D4, D5 and D6 in surface water were 38.1%, 95.2% and 100%, respectively, and the range of total concentration of cVMSs was 13.66-77.90 ng·L^-1, with an average of 47.82 ng·L^-1. The detection rates of D4, D5 and D6 in the sediments were 66.7%, 86.7% and 100%, respectively, and the range of total concentration of cVMSs was 0.56-49.74 μg·kg^-1, with an average of 13.95 μg·kg^-1. The detection rates of D4, D5 and D6 in the soils were 66.7%, 20% and 100%, respectively, and the range of total concentration of cVMSs was 1.90-7.05 μg·kg^-1, with an average of 3.57 μg·kg^-1. The highest detected concentration of D6 was in surface water and soil, while in sediment it was D5. Compared with the results from other regions at home and abroad, concentrations of cVMSs in Nanjing Section of Chuhe River were in the middle-low level. The ecological risk assessment results show a medium/high risk of cVMSs in Nanjing section of Chuhe River.