Monitoring of trichloromethane and carbon tetrachloride in drinking water and health risk assessment of Changsha City from 2020 to 2022
Objective To monitor and evaluate the concentration levels of trichloromethane and carbon tetrachloride in urban drinking water in Changsha City,and to evaluate the potential risks to human health.Methods From 2020 to 2022,according to the water supply range of urban water plant in Changsha,109 monitoring points were selected,and a total of 1 292 water samples were collected.We detected the concentration of trichloromethane and carbon tetrachloride in urban water samples according to the<Standard Inspection Method for Drinking Water>(GB/T 5750-2006),and the risk assessment was conducted by using The four-step environmental health risk assessment method.Results The detection rate of trichloromethane was 93.5％,and the concentration range was ND～0.059 4;The detection rate of carbon tetrachloride was 6.73％,and the concentration range was ND～0.0010.According to the<Drinking Water Sanitation Standard>(GB-5749-2006),the qualified rate of both pollutants was 100％.The health risk assessment showed that the non-carcinogenic risks of trichloromethane and carbon tetrachloride exposed via drinking water routes during 2020-2022 were 5.20×10-2 and 4.33 × 10-4,respectively,and the carcinogenic risks were 1.61×10-5 and 1.21 × 10-7,respectively.The concentration and health risk of trichomethane in out-factory water were lower than those in secondary and tip water.The concentrations and health risks of trichothane were higher in high flow period than those in low flow.Conclusions From 2020 to 2022,the median concentration of trichloromethane in urban drinking water in Changsha showed a downward trend year by year,and the risk of carcinogenic exposure through drinking water route was within the acceptable range,but it should be paid attention to.The detection rate and concentration of carbon tetrachloride were both low,and the health risk was less.
万方数据
