Occurrence characteristics and ecological risks of fluorescent whitening agents in water bodies around a landfill

The occurrence and ecological risks of fluorescent whitening agents (FWAs) in landfill leachate and surrounding water bodies were reported in this study. Both traditional and emerging FWAs were prevalent in the target samples, but at the ng L^-1 levels. The total FWA concentrations exhibited a gradual decreasing trend along the groundwater flow direction. Although the landfill is a potential source of ionic FWAs, it has effectively restricted the diffusion of these contaminants into surrounding aquatic environment. Our analysis revealed that the relative proportions of dissolved organic matter (DOM) components (C1, C2, C3) could serve as reliable indicators of the extent to which water bodies are impacted by the adjacent landfill. In other words, the greater the landfill's influence on the water body, the lower the percentage of C1 and the higher the percentages of C2 and C3 in the water's DOM, and vice versa. The ecological risk assessment revealed that all of the groundwater and surface water samples reached high-risk levels, with six ionic FWAs contributing more than 85 % of the total RQsum values at most of the monitoring sites, and five of these ionic FWAs were identified as high toxicity priority contaminants. These findings underscore the need for greater attention to the environmental impacts of ionic FWAs, especially their significant effects on surface water, while also suggesting that agricultural plastic waste and residential laundry wastewater discharges may have a greater influence on surrounding water bodies than landfill leachate, warranting prioritized investigation.