Health Risk Assessment on Pesticide Residues in Drinking Water in Shenzhen

Objectives: To conduct health risk assessment of drinking water pesticide residues and its annual trend analysis in Shenzhen City. Methods: The samples of product water, pipe water and secondary supply water from 2011 to 2013 were collected and analyzed. The evaluation models of 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) were recommended by the U.S. Environmental Protection Agency (US EPA). Results: The results showed that the maximums of the measured indicators in the above were controlled in accordance with the National Health Standards (GB5749-2006) published by Ministry of Health in China. The adults and children’s health indices (HIs) of the 12 non-carcinogenic materials were greater than 1 (2.323 - 6.312). Dimethoate residue in factory and peripheral water was the largest risks of harm among the non-carcinogenic pollutants measured. And its HIi (Its Hli) was 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 × 10-3 in 2011, 2340. 18 × 10-3 in 2012 and 2431. 97 × 10-3 in 2013, and HIT on children was 2965. 07 × 10-3 in 2011, 2986. 77 × 10-3 in 2012 and 3103. 93 × 10-3 in 2013, respectively. This study also suggested that the average risk of peripheral water samples (HIT was equal to 2619. 64 × 10-3) was greater than the factory samples’ (HIT was the same as 2366. 92 × 10-3), and the children’s health risk was greater than the adults’. Conclusions: Health risks of drinking water pesticide residues in Shenzhen have exceeded the threshold values. The dimethoate was the main hazard and had been rising annually, and the children’s health risk was greater than the adults’.