Health risk of 10 chemicals in drinking water in Hefei from 2020 to 2022
Objective To understand the health risks of 10 chemicals in drinking water in Hefei and provide a basis for risk management of drinking water.Methods From 2020 to 2022,the samples of drinking water in Hefei was collected for water quality monitoring.The concentration levels of 10 chemical substances,including arsenic,cadmium,hexavalent chromium,aluminum,manganese,zinc,fluoride,nitrate,trichloromethane and carbon tetrachloride,were determined.The health risk assessment model recommended by the US EPA was used for health risk assessment.Results A total of 2 282 water samples were collected,and 5 chemicals including trichloromethane,aluminum,manganese,fluoride and zinc exceeded the standard to varying degrees,with a rate of exceeding the standard(1.8%to 0.04%).The total risk of cancer caused by oral intake of tap water was 7.71 ×10-6,with arsenic and trichloromethane having carcinogenic risks of 5.98×10-6 and 1.59× 10-6,respectively,with arsenic having the highest contribution rate.The non carcinogenic risk was 0.20,with fluoride contributing the most(0.09).Trichloromethane and nitrate were showing an increasing trend year by year.The total risk during the wet season was higher than that during the dry season,with arsenic,chromium,fluoride and trichloromethane having higher risks during the wet season than during the dry season.The total risk and trichloromethane risk increased in the order of finished water,terminal water and secondary water supply.The risk for men was higher than that for women,and the total cancer risk in Hefei was higher than that in counties(cities).The cancer risk ranged from 6.41×10-6 to 8.58×10-6,and the overall risk in each region was mainly affected by trichloromethane.Conclusion In this survey,the investigated chemicals in drinking water in the Hefei area present a certain risk of cancer,however,is at an acceptable level.The non carcinogenic risk is relatively low,and more attention should be paid to the treatment of arsenic,trichloromethane and fluoride.