Pollution of diamide insecticides in Chinese basins: Nationally spatial heterogeneity and unexpected exposure risks

As green alternatives of developed pesticides, diamide insecticides (DAIs) now are new choice to protect crops in China. Extensive applications inevitably lead to their considerable releasing into the environment, especially aquatic system through agricultural runoff. However, large-scale investigation of their pollution characteristics in surface water is still rare. In this work, a nationwide survey elucidated the widespread occurrence of DAIs in rivers across 9 major Chinese basins, with their median concentrations from 0.96 ng/L (Chlorantraniliprole, CTP) to 17 ng/L (Cyantraniliprole, CYTP). While CYTP is the predominant contaminant in riverine water, While CYTP is the predominant contaminant in riverine water, its regional pollution features were different, which was associated with local applied crop-specific insecticides. Noteworthily, broflanilide (BFA) was the DAI with the highest screening-level ecological concern especially for dwelling midges (Chironomus dilutus), even though its pollution level is not the most serious. This pattern indicates that ecological risk is not determined by environmental concentration alone, but is strongly influenced by compound-specific toxicity. Furthermore, in comparison to adults, children showed modeled cumulative waterborne exposure about 2.4 times that of adults cumulative waterborne exposure of DAIs under the modeled raw source-water ingestion scenario, although all calculated Hazard Quotients (HQ) remained below 1. This work provides a preliminary nationwide snapshot of DAIs pollution in Chinese surface water. The spatial heterogeneities of contamination patterns and potential exposure risks both highlights the urgent need to study the in vivo and in vitro biological impacts of DAIs in the future.