Objective To analyze the type distribution and pollution concentration levels of insecticides and fungicides in source water and finished water in the Yangtze River and Yellow River basins in China, and to provide important references for the monitoring and research of pesticide pollutants in larger regions in China.
Methods From December 2022 to February 2023, a total of 132 source water and finished water samples were collected from 66 typical municipal waterworks in the Yangtze River and Yellow River basins. The online solid-phase extraction high-performance liquid chromatography-tandem mass spectrometry was used to determine 48 insecticides and 13 fungicides in the samples, and the pollution characteristics of insecticides and fungicides in drinking water in the Yellow River and Yangtze River basins were analyzed.
Results A total of 42 out of 61 insecticides and fungicides were detected, with the concentrations ranging from 0.1 ng/L to 606.5 ng/L and the median of 0.1 ng/L to 10.4 ng/L. There were 10 insecticides and fungicides with a detection rate higher than 50%, including metalaxyl, triazolone, tebuconazole, isoprothiolane, acetamiprid, tricyclazole, thiamethoxam oxazine, imidacloprid, fenobucarb, and carbendazim. The total concentration of insecticides and fungicides measured in the source water and finished water ranged from 0.1 ng/L to 875.3 ng/L and from 0.2 ng/L to 491.4 ng/L, with the medians of 33.3 ng/L and 16.4 ng/L, respectively. The total concentration measured in the source water samples was significantly higher than that in the finished water samples (z=-5.29, P < 0.001). The total concentration of insecticides and fungicides in samples from the Yellow River basin (n=70) and the Yangtze River basin (n=62) ranged from 0.1 ng/L to 875.3 ng/L and from 0.5 ng/L to 313.6 ng/L, with the medians of 10.8 ng/L and 39.9 ng/L, respectively. The total concentration of insecticides and fungicides in the Yangtze River basin was significantly higher than that in the Yellow River basin (z=-4.20, P < 0.001), but there was no significant difference in the total concentration of insecticides between the two basins (z=-1.06, P=0.289).
Conclusion The pollution of insecticides and fungicides is widespread in the source water and drinking water in the Yellow River and Yangtze River basins, with the concentration level at ng/L, characterized by a large variety of pollutant types and low concentrations. In some monitoring sites, the total amount of insecticides and fungicides is close to or exceeds the requirement of the European Union Drinking Water Directive that the total amount of pesticides should be less than 0.5 μg/L. Therefore, attention should be paid to the total amount of pesticide pollutants in drinking water in China, and further attention should be given to the insecticides and fungicides with high detection rates outside the standards for drinking water quality.
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