National survey and risk assessment of haloacetic acids in drinking water in China for reevaluation of the drinking water standards

Nine haloacetic acids were determined in finished water samples from 117 drinking water supply plants,using a specific and sensitive UPLC-MS/MS method.Of nine haloacetic acids,dichloroacetic acid and trichloroacetic acid showed high detection frequencies with 78.6% and 81.2%,and concentrations with 3.47μg/L and 3.31μg/L,respectively.The expected lifetime cancer risk of dichloroacetic acid associated with uptake of drinking water in China was 5.72×10-6,showing a relatively low risk.The concentration of trichloroacetic acid in finished water which exceeded the health guideline value of 20μg/L was estimated to be 1.7%.Based on the results of risk assessment and the national survey of haloacetic acids,the criteria of dichloroacetic acid and trichloroacetic were suggested to be 16μg/L and 20μg/L,respectively.