Ecotoxicity and Risk to Zooplankton of a Novel Insecticide Used in Rice Paddies in a Simulated Ecosystem.

This article focuses on assessing the ecological risks of tetrachlorantraniliprole, a novel diamide insecticide, to aquatic nontarget organisms in rice paddy ecosystems. Using an outdoor mesocosm experiment and the multimedia paddy-pond model TOPRICE, the study found that tetrachlorantraniliprole primarily remains in the water phase, dissipates rapidly (half-life 0.79–1.5 days), but exerts toxic effects on zooplankton communities, especially cladocerans like Simocephalus vetulus. A no-observed-ecological-adverse-effect concentration (NOEAEC) of 7.74 µg/L was established for zooplankton, and model simulations indicated a relatively high risk when the insecticide is applied during the rice tillering stage in major Chinese rice-producing regions. The findings support that current Tier 1 risk assessment approaches provide adequate protection but recommend risk mitigation measures, such as timing restrictions, to minimize impacts on aquatic ecosystems.