Occurrence, distribution, and risk assessment of pesticides in surface water and sediment in Jiangsu Province, China

The occurrence and distribution of 157 pesticides were investigated in surface water and sediment in Jiangsu Province, China. Gas chromatography–mass spectrometry was used to analyze and quantify these pesticides, and the risk quotient method was used to evaluate their respective environmental risk. The results showed that 91 pesticides were detected in surface water. The organophosphates (OPPs), fungicides, and amide herbicides were predominant. The total concentration in surface water ranged from 63.7 to 22,463 ng/L, 3.90 to 7262 ng/L, and ND to 34,120 ng/L, respectively. The mean concentration was 3479 ng/L, 1644 ng/L, and 1878 ng/L, respectively. The concentration range of detected pesticides in the Yangtze River Basin was generally lower than that in the Huai River Basin. In sediment samples, a total of 63 pesticides were detected. OPPs and amide herbicides were also ranked highest; the total concentration in sediment samples ranged from 2951 to 47,739 ng/g and 106 to 12,996 ng/g, respectively. And the mean concentrations was 6971 ng/g and 5130 ng/g, respectively. Suqian City had the highest concentration for OPPs and amide herbicides in the Huai River Basin, followed by Huai’an City, while Nanjing City and Yangzhou City ranked highest in the Yangtze River Basin. The spatial distribution of pesticides in Jiangsu Province indicated a concentration significantly higher in the western and northern regions than in the eastern and southern regions, and a concentration generally higher in lakes than in rivers. The risk assessment results showed that OPPs, fungicides, amide herbicides, organochlorines, and triazine herbicides in most surface water samples posed a high risk and had regional pollution characteristics. In sediment samples, organochlorines, carbamates, other herbicides, and other insecticides posed a high risk in northern Jiangsu Province, whereas OPPs, amide herbicides, and triazine herbicides posed high risks everywhere in Jiangsu Province.