Risk Assessment of Lead and Cadmium in Drinking Water for School use in Nakhon Si Thammarat Province, Thailand.

This research aimed to evaluate children's health risk based on the concentration of lead (Pb) and cadmium (Cd) in the drinking water used by 44 primary schools. Samples were collected from bottled water, tap water, filtered tap water and raw water, for a total of 146 samples, between 1 September 2018 and 31 January 2019. The concentrations of Pb and Cd in drinking water samples were determined by graphite furnace atomic absorption spectrometry. The results showed that the concentration of Pb and Cd in bottled water samples were in the range of non-detected (ND)-0.0180 mg/L and ND-0.0013 mg/L, respectively. The concentration of Pb and Cd in tap water samples ranged from ND-0.0250 mg/L and ND-0.0042 mg/L, respectively, from ND-0.005 mg/L and ND- 0.0021 mg/L, respectively, in filtered tap water samples and from ND-0.0400 mg/L and ND-0.0049 mg/L, respectively, in raw water samples. The summation of the total hazardous index (HI)-values of bottled water samples, tap water samples, filtered tap water, and raw water samples were less than 1, was considered health-protective. The results will provide the direct evidence needed by school managers to warn learners about the health risk of ingestion exposure among children.