A study conducted in the Prado Wetlands in Southern California investigated the spatiotemporal distribution and removal efficiency of six neonicotinoid insecticides. The wetlands, which receive urban runoff and wastewater effluent, showed varying levels of neonicotinoid concentrations depending on the location and vegetation density. The highest concentrations were found in shallow, vegetation-free cells, while densely vegetated cells exhibited the highest removal efficiency. The study found that neonicotinoids, such as imidacloprid and dinotefuran, were frequently detected in surface water, with removal efficiencies ranging from 16.9% to 90.2% depending on the cell type. Principal component analysis indicated that pH and temperature were key factors influencing removal. The study also assessed the ecological risk of neonicotinoids using risk quotients (RQs), finding that most compounds posed low ecological risk. The results highlight the effectiveness of constructed wetlands in removing neonicotinoid insecticides through uptake by wetland plants, photolysis, and microbial degradation. The study underscores the importance of considering vegetation density and hydraulic retention time in optimizing wetland performance for neonicotinoid removal. The findings suggest that constructed wetlands can serve as an effective and cost-efficient method for mitigating neonicotinoid contamination in surface water.A study conducted in the Prado Wetlands in Southern California investigated the spatiotemporal distribution and removal efficiency of six neonicotinoid insecticides. The wetlands, which receive urban runoff and wastewater effluent, showed varying levels of neonicotinoid concentrations depending on the location and vegetation density. The highest concentrations were found in shallow, vegetation-free cells, while densely vegetated cells exhibited the highest removal efficiency. The study found that neonicotinoids, such as imidacloprid and dinotefuran, were frequently detected in surface water, with removal efficiencies ranging from 16.9% to 90.2% depending on the cell type. Principal component analysis indicated that pH and temperature were key factors influencing removal. The study also assessed the ecological risk of neonicotinoids using risk quotients (RQs), finding that most compounds posed low ecological risk. The results highlight the effectiveness of constructed wetlands in removing neonicotinoid insecticides through uptake by wetland plants, photolysis, and microbial degradation. The study underscores the importance of considering vegetation density and hydraulic retention time in optimizing wetland performance for neonicotinoid removal. The findings suggest that constructed wetlands can serve as an effective and cost-efficient method for mitigating neonicotinoid contamination in surface water.