Objective To comprehensively investigate the levels of exposure and distribution characteristics of trihalomethanes (THMs) in drinking water in Guangzhou City, and evaluate the health risks of different groups of children, adolescents and adults, and to provide data and evidence for protecting human health and promoting risk control of drinking water. Methods According to the technical requirements of the ^"Standards for Drinking Water Quality Testing Methods^" (GB/T 5750-2023), the concentration of THMs, including trichloromethane (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and tribromomethane (TBM) in drinking water in Guangzhou City from 2023-2024 were detected. The health risk model recommended by USEPA was used for risk assessment．Results TCM, BDCM and DBCM were detected in the factory water and terminal water, with TCM contributing the most. There was a statistically significant difference (P<0.05) between the wet and dry seasons, and the concentration of TCM in the wet season was higher than that in the dry season. Among the multiple exposure factors, the amount of exposure through drinking water intake was much greater than that through skin absorption. The carcinogenic risk index of THMs for children, adolescents, and adults was 22.0×10^-6, 12.2×10^-6, and 11.4×10^-6, respectively, while the non-carcinogenic risk was less than 1. Conclusion The exposure risks of THMs in children, adolescents, and adults is within an acceptable range, but monitoring needs to be strengthened, with a particular focus on children.

100 ?g/L), 36(2.90%)male and twenty four (2.09%)female. BLLs(G) in Baiyuen (suburb) children(60.33 ?g/L) was the highest among three districts, Yuxiu (downtown) was 58.09 ?g/L and Zengcheng (countryside)was 56.72 ?g/L. Linear regressions (stepwise) were taken with geometric BLLs as dependent, 34 items as independents in SPSS 11.5. Fathers with lower diploma, narrower houses, better aired houses, fewer hand washings and sucking fingers were the risk factors for children high BLLs. Conclusion BLLs in suburb children become the highest after unleaded gasoline used in Guangzhou. The housing circumstance and hygienic behavior of children may effect the blood lead level.