Assessment of organochlorine pesticides contamination in underground rivers in Chongqing, Southwest China

To explore the potential health hazards of organochlorine pesticides (OCPs) in karst areas, HCHs (including α-HCH, β-HCH, γ-HCH and δ-HCH) and DDTs (including p,p'-DDE, p,p'-DDD, o,p'-DDT and p,p'-DDT) in underground rivers of Chongqing were analyzed, and health risks from OCPs through drinking water were assessed for adults and children. The results showed that the concentrations of OCPs in surface water from underground rivers were in the range of 2.25–29.37 ng l− 1 for HCHs (sum of α-HCH, β-HCH, γ-HCH, δ-HCH), and 0.19–35.25 ng l− 1 for DDTs (sum of p,p'-DDE, p,p'-DDD, o,p'-DDT and p,p'-DDT). δ-HCH and p,p'-DDT were the dominant HCHs and DDTs, respectively. In comparison with similar results reported around the world, the level of OCPs in this research was in the mid-range. Ratios of certain metabolites to their parent compounds suggested that HCHs in water from underground rivers mainly came from recent input of lindane, while the residues of DDTs were from earlier application of technical DDT and new input of dicofol. The analysis of health risk assessment indicated that risks from OCPs in most rivers would not be risky to human health according to the acceptable risk level, while carcinogenic effects caused by α-HCH might occur if drinking water from Lao Longdong (LL). α-HCH and β-HCH were the dominating factors for carcinogenic and non-carcinogenic risks, respectively. Risks of OCPs for children were much higher than those caused by OCPs for adults.

► The first study to report organochlorine pesticides (OCPs) contamination in karst water from karst regions.
► The level of hexachlorocyclohexanes (HCHs) mainly contribute to current usage of lindan.
► Children was a population group sensitive to the health risks of pollutants.