[Health risk assessment on pesticide residues in drinking water in Shenzhen]

To conduct a health risk assessment of pesticide residues and its annual trend analysis in drinking water in Shenzhen City.

The water quality monitoring data of product water, pipe water and secondary supply water during from 2011 to 2013 were collected and analyzed. The risk evaluation models recommended by the U. S. Environmental Protection Agency (USEPA) were employed to perform health risk assessments for children and adults on the 12 non-carcinogenic materials (namely, heptachlor, pentachlorophenol, hexachlorocyclohexane, hexachlorobenzene, DDT, malathion, glyphosate, dimethoate, bentazone, atrazine, chlorothalonil, furadan). Results The results of the analysis for water quality from 84 factory samples, 11 peripheral samples and one secondary supply water sample showed that all of the measured indicators in the above mentioned water samples met the National Health Standards (GB 5749-2006) published by Ministry of Health of the People's Republic of China. The adults and children' s health indices (HIs) of the 12 non-carcinogenic materials were greater than 1 (2. 323 - 6. 312). Dimethoate in factory and peripheral water samples posed the largest risks of harm among the non-carcinogenic pollutants measured. And its HIi were also greater than 1 (1. 995 - 5. 094) and followed by hexachlorobenzene and heptachlor. Annual rising trend on health risk of the 12 pesticide residues indicated that their HIT on adults was 2323. 18 x 10(-3) in 2011, 2340. 18 x 10(-3) in 2012 and 2431. 97 x 10(-3) in 2013, and on children 2965. 07 x 10 (-3) in 2011, 2986. 77 x 10(-3) in 2012 and 3103. 93 x 10(-3) in 2013, respectively. This study also suggested that the average risk of peripheral water samples (HIT was equal to 2619. 64 x 10(-3) was greater than that of factory samples (HIT was same as 2366. 92 x 10(-3), and more children' s health risk than adults' risk.

Health risks of pesticide residues in drinking water in Shenzhen have exceeded the threshold value and dimethoate was the main hazard and more children's health risk than adults' risk. Furthermore, there was an annual rising slowly trend on health risks of pesticide residues in drinking water.