Abstract: In order to evaluate the concentration of trace elements in drinking water and assess their potential hazards to human health, we collected a total of eighty terminal tap water samples from residents’ homes, along with three river water samples from water sources in the urban area of Chongqing. Subsequently we measured the concentrations of As, Ba, Cr, Cu, Mo, Ni, Sb, Se, and Zn in these water samples, and assessed the health risks of these elements in drinking water by using the health risk assessment model recommended by USEPA. Results revealed that 1) The average (arithmetic mean, the same hereinafter) concentrations of the nine trace elements in drinking water meet the national standards for drinking water quality. 2) The total health risks of trace elements to children and adults are 8.72×10^-5 a^-1 and 3.56×10^-5 a^-1, respectively, which falls within the maximum acceptable standard (10^-6-10^-4 a^-1) recommended by USEPA.However,the total health risks to children are higher than those for adults.3) The carcinogenic risks posed by Cr and As for children and adults are 8.54×10^-5 a^-1 and 1.62×10^-6 a^-1, 3.48×10^-5 a^-1 and 6.74×10^-7 a^-1, respectively, lower than the maximum acceptable levels (10^-4 a^-1) set by USEPA. In conclusion, Cr and As are primary sources of health risks in the drinking water of main urban area of Chongqing. Thus, monitoring and management of Cr and As shall be strengthened in future.

Key words: trace elements, health risks, terminal tap water of residents, Arsenic, Chromium, Chongqing city