A nationwide survey of four diamide insecticides (DAIs) in rivers across 47 Chinese cities and nine major river basins has found widespread contamination, with cyantraniliprole (CYTP) the most abundant compound and broflanilide (BFA) posing the greatest screening-level ecological concern for benthic midges. The study, published in Environmental Chemistry and Ecotoxicology, provides the first nationwide pollution snapshot of DAIs in Chinese rivers, revealing concentrations from below detection limit to 119 ng/L and a national median total concentration of 40 ng/L.
Cyantraniliprole was detected at every sampling site, with a median concentration of 17 ng/L, and contributed most in southern basins. Broflanilide made a larger contribution in northern basins, a pattern researchers linked to local crop-planting and crop-specific pesticide-use patterns rather than land-use or meteorological variables. Corresponding author Yanhao Zhang noted that the chemical composition patterns varied by region, reflecting agricultural practices.
Despite not being the most abundant pollutant, broflanilide emerged as the main screening-level driver of risk for the benthic midge Chironomus dilutus because its species-specific chronic effect threshold was much lower. Screening risk quotients for BFA exceeded 1 at 22% of sampling sites. For Daphnia magna, the combined risk of the four DAIs exceeded the medium-risk threshold at 22% of sites, while cumulative risks for fish and aquatic plants remained negligible in the screening framework.
The study also modeled a conservative scenario of direct ingestion of untreated surface water. The 95th-percentile cumulative daily intake for children aged 0–6 years was 9.1 ng/kg body weight/day, about 2.4 times the adult value of 3.7 ng/kg body weight/day. All hazard quotients remained below 1, indicating no immediate health concern, but the higher exposure for children underscores the need for additional attention to sensitive groups.
These findings matter because they show that environmental concentration alone does not tell the whole risk story. "Monitoring should combine nationwide occurrence data with compound- and species-specific toxicity, while giving additional attention to sensitive groups such as children," Zhang said. The research was funded by the National Natural Science Foundation of China (22376190 and 22576191) and the Natural Science Foundation of Henan Province (242300421128). For more information on related innovations, visit http://chuanlink-innovations.com.
