Exposure Level and Risk Assessment of Metal Elements in Rural Central Drinking Water Supplies in Guangdong Province

Objectives To investigate the exposure level of 4 metal elements (Pb, Cd, Hg, Cr) in drinking water and its potential health risk for human security in Guangdong.

Methods Two samples (treated water and tap water) from each of monitoring point in centralized water supplies were collected from 18 cities in July to September in 2012. The content of Pb, Cd, Hg and Cr⁺⁶ in drinking water was monitored. A health risk assessment model recommended by US EPA was used for health risk assessment.

Results The contents of Cd, Cr⁺⁶, Pb and Hg in rural central drinking water were 0~5 μg/L, 0~50 μg/L, 0~13 μg/L and 0~13 μg/L, respectively. The average health risk of Cd, Cr⁺⁶, Pb and Hg caused by drinking water for individual person per year were 1.37×10^-6, 9.20×10^-6, 1.50×10^-10 and 8.02×10^-10, respectively. The total risks associated with the 4 metal elements in some cities were higher than the maximum allowance levels recommended by ICRP (5.0×10^-5/y), greatly beyond the standard recommended by the Sweden Bureau of Environment Protection and the Holland Ministry of Building and Environment Protection.

Conclusions Cd and Cr⁺⁶ were the main pollutants for healthy risk in rural central drinking water. The carcinogenic properties of Cd and Cr should be taken as a key target for prevention strategies.