Objective To assess the health risks of heavy metal elements and disinfection by-products in tap water and water produced from two types of water purifiers, and understand the potential effects of the two kinds of substances on human health and the effects of selected water purifiers on drinking water health risk improvement.
Methods A total of 25 samples of tap water and the tap water treated with two types of water purifiers were collected from April to June in 2017. The concentrations of six heavy metal elements, Al and five disinfection by-products in the water samples were detected and analyzed. Furthermore, the health risks of heavy metal elements and disinfection by-products via drinking water were assessed based on the "four-step" health risk assessment model recommended.
Results For heavy metal elements:the carcinogenic risks in all three kinds of drinking water were dominated by Cr, and the order of the risks from high to low were ultrafiltration water > tap water > kinetic degradation fluxion (KDF) water; the noncarcinogenic risks were dominated by Pb and Cd, and the order of the risks were tap water > ultrafiltration water > KDF water. For disinfection by-products:the carcinogenic risks in tap water and ultrafiltration water were dominated by bromodichloromethane; the non-carcinogenic risk in tap water was dominated by bromodichloromethane, that in ultrafiltration water was dominated by trichloromethane, and KDF water had no non-carcinogenic risk of disinfection by-products. The total carcinogenic risk of tap water was dominated by disinfection by-products, and the total non-carcinogenic risk was dominated by heavy metal elements. Both carcinogenic risk and non-carcinogenic risk in the drinking water treated with the two types of water purifiers were dominated by heavy metals.
Conclusion The health risks of heavy metal elements and disinfection by-products via the three kinds of drinking water are within acceptable limits. Both types of water purifiers can reduce total carcinogenic risk and total non-carcinogenic risk. The effect of KDF water purifier is better than that of ultrafiltration water purifier in terms of the health risk assessment.
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