Exposure condition and health risk assessment of three metals and metalloids in drinking water of a city in Northwest China in 2021
Objective To master the exposure of three metals and metalloids in drinking water in a city in Northwest China,assess the health risks to human body through drinking water,so as to provide scientific basis for health risk management of drinking water.Methods According to the water supply scope of a centralized water supply project in a city in Northwest China in 2021,114 monitoring points were set up and 114 water samples were collected in the dry season and the wet season respectively for water quality monitoring.The three metals and metalloids in drinking water were evaluated according to the GB 5749-2006 Sanitary Standards for Drinking Water.The health risk assessment method recommended by U.S.Environmental Protection Agency(US EPA)was used for the carcinogenic risk assessment.Results A total of 228 water samples were monitored,and the standard-reaching rate was 100.00％.The median concentrations of the three metals and metallids were As 0.50×10-5 mg/L,Cd 0.25×10-5 mg/L,Cr6+2.00×10-5 mg/L,and the carcinogenic health risk levels were Cr6+＞As＞Cd,Rc was 3.77×10-5.The concentration level and health risk level of As in the dry season were higher than those in the wet season.The concentration level and health risk level of Cr6+in the wet season were higher than those in the dry season.The concentration level and health risk level of As and Cr6+were secondary water supply tap water>factory water.The concentration level and health risk level of Cd in surface water were higher than those in groundwater.There were no statistically significant differences in the concentration level and health risk level of Cd among different water sample type and water period(all P＞0.05).There were no statistically significant differences in the concentration level and health risk level of As and Cr6+among different water sources(all P＞0.05).Conclusions The contents of three metals and metalloids in drinking water in a city in Northwest China is up to standard,and the total carcinogenic risk value is 10-5 orders of magnitude,which is in the acceptable range.The highest risk of carcinogenic health is Cr6+,followed by As,suggesting that the city should pay attention to the potential harm of Cr6+and As to human health in the future prevention and control of drinking water pollution,and strengthen the monitoring and evaluation of drinking water.
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