Soil environmental quality and risk assessment under combined organic pollution in a typical sewage irrigated area

Due to the shortage of freshwater and the depletion of groundwater, reuse of wastewater for crop irrigation has become essential, although many pollutants, such as antibiotics, are also introduced into the soil-groundwater system. In order to identify the distribution and transport mechanisms of organic pollutants in the "irrigation wastewater-soil-crop" system under long-term soil irrigation conditions and their potential ecological and health risks, soil samples were collected from five sampling sites in Wangyang River basin, a typical sewage irrigation area in North China. The results of the risk assessment showed that the risk quotients (RQ) of sulfamethoxazole (SMZ), naphthalene (Nap), hexachlorocyclohexane (HCH), and dichlorodiphenyltrichloroethane (DDTs) was greater than 1, indicating that their accumulation in root zone soil was at high risk. The non-carcinogenic risk (HQ) of bis (2-ethylhexyl) phthalate (DEHP) was the largest, reaching 0.41 and 0.16 for adults and children, respectively, and the carcinogenic risk (CR) value was 0.00061, which exceeded the limit of 1 × 10 −6 , indicating that DEHP poses a potential carcinogenic risk to human health.