Occurrence of Volatile Organic Compounds and Associated Risk Assessments in Dongting Lake, China

Large amounts of volatile organic compounds are released into the environment, and most have been shown to be harmful to humans. Dongting Lake is one of the important freshwater lakes in China, but there are few studies on the existence, distribution and risk assessment of volatile organic compounds in its water. This study investigated the emergence of volatile organic compounds (VOCs) within the surface water of Dongting Lake. A total of 15 different VOCs concentrations were measured in water samples from 21 sampling points. Fifteen kinds of VOCs have been detected; the one with the highest mean concentration is 1, 2-dichlorobenzene (1.039 mu g/L), and the lowest is 1, 3, 5-trimethylbenzene (0.0034 mu g/L). Of these, seven VOCs had a detection frequency of 100%. The total concentration of volatile organic compounds in the Nanzui waters was the highest among all the test sites. The Risk quotients (RQ) model has been adopted for evaluating the VOCs ecological risk, the RQtotal values of five sampling sites were higher than 1.0, indicating that the target compounds were at high risk or medium risk for related sensitive aquatic organisms. In addition, the carcinogenic risk of benzene is 2.45 x 10-6, and the environmental exposure of benzene has a certain risk to human body but is within an acceptable range.The non-carcinogenic risks of toluene, benzene, ethylbenzene as well as xylene (BTEX) have been all less than 1.0, so it can be considered that there is no non-carcinogenic risk of BTEX to human body. Therefore, VOCs in Dongting Lake will not cause serious impact on human body, but it will pose a threat to aquatic organisms in some water areas.