Ecological and health risk assessment of organochlorine pesticides in an urbanized river network of Shanghai, China

Background Organochlorine pesticides (OCPs) are currently still threatening the ecological environment and people's health. However, studies that investigate OCP pollution levels in an urbanized river network of an entire city with a high density of rivers, such as Shanghai, have rarely been reported. In addition, due to the pressure of high population densities, ecological risk and health hazard assessments of OCPs in river networks are a knowledge gap that needs to be urgently filled. Thus, in this study, the concentrations, distribution, and partitioning of OCPs are evaluated in an ecological and health risk assessment for the urbanized river network of Shanghai. The goal is to establish connections among OCP residues and establish their impacts on ecological and human health. Results The concentrations of 26 OCPs in the urbanized river network of Shanghai ranged from 43.90 to 342.74 ng/L, with a mean value of 181.34 ng/L. Some OCPs formed triangle-shaped areas with higher local ecological risks than other areas, and there were nine OCPs of high risk in some areas. The health risk assessment results showed that the ranking of the incremental lifetime cancer risk (ILCR) for dermal contact according to age and gender was adults > children > seniors > adolescents, and females > males, while the ranking of the ILCR caused by mistaken oral intake was adults > children > adolescents > seniors, and females > males. The non-carcinogenic risk hazard index (HI) values of both exposure routes were less than one. Conclusion OCP concentrations in the northern and southern regions of Shanghai were significantly higher than in other regions, and the partition coefficient (K-p) values of the n-ary sumation (26) OCPs were negatively correlated with the total suspended solids' (TSS) contents (p < 0.01). The ecological risks were relatively higher in agricultural areas. The ILCR for dermal contact and mistaken oral intake were generally low, except for adults, whose ILCR caused by dermal contact were at moderate risk. In addition, OCPs in river waters did not pose significant non-carcinogenic health hazards for a majority of the people.