Assessing neonicotinoid accumulation and ecological risks in the aquatic environment of Yangtze River Basin, China

Neonicotinoids (NNIs) constitute commonly used pesticides across various regions, however, the lack of research and data on its long-term effects and threshold levels within specific ecosystems have left an important knowledge gap. This study aimed to comprehensively examine NNI concentrations and their potential impacts on human health and aquatic organisms in the region of the Yangtze River Basin (YRB). The study employed datasets on seven commonly applied NNIs across 244 surface water samples collected from 12 distinct geographic sites within the YRB. The relative potency factor was used to evaluate human exposure risks, while the species sensitivity distribution could estimate acute and chronic hazardous concentrations for 5% of species (HC5) for NNIs impacting aquatic organisms. Analysis revealed varying NNI concentrations across the sampled sites, with thiacloprid recording the lowest concentration at 0.1 ng L^-1, and dinotefuran recording a high concentration of 408 ng L^-1. The observation indicated NNI concentration declined at sampling sites downstream of the YRB. Infants were identified as the most vulnerable to NNI exposure, with an estimated daily intake of 40.8 ng kg^-1 bw d^-1. The acute HC5 was determined at 946 ng L^-1 and a chronic HC5 at 338 ng L^-1, to NNI hazards. These findings highlight the urgent need for a more comprehensive understanding of the ecological implications and hazards posed by NNIs within the YRB. Variations in NNI concentrations across sites, potential risks to human health, and increased vulnerability of aquatic organisms from this study underscore the necessity for further research and concerted efforts to mitigate these ecological threats in the region.