Occurrence, Distribution, and Ecological Risks Assessment of Phthalate Esters (PAEs) in Multiple Environmental Media of Plateau Lake in Southwestern China:A Case Study of Caohai Lake

Phthalate esters (PAEs), widely used plasticizers, have attracted increasing attention due to their persistence and congener‐dependent ecological risks in aquatic systems. This study examined Caohai Lake, a representative plateau lake in Guizhou, China, where water, sediment, aquatic plants, and fish were sampled from 20 sites during dry and wet seasons. Six common PAEs (DMP, DEP, DBP, BBP, DEHP, and DNOP) were analyzed for spatial distribution, seasonal variation, and migration characteristics. The mean ∑ 6 PAE concentrations in water, sediment, with supplementary data from surrounding soils, were 27.17 ng/L, 48.27 μg/kg dw (water and sediment, respectively) during the dry season, increasing to 158.56 ng/L, and 248 μg/kg dw in the wet season; PAE concentrations in surrounding soils were 105.3 μg/kg dw and 248 μg/kg dw in the dry and wet seasons, respectively. DBP and DEHP were the dominant monomers in all media. Aquatic plants showed notable bioaccumulation, while fish exhibited limited accumulation. Ecological risk assessment using risk quotient analysis identified DEHP as the primary concern in both seasons, with DBP posing higher risk in the wet season, whereas DMP and DEP showed negligible risks. Migration analysis suggested that DMP, DEP, and DBP tended to desorb from sediments into overlying water, while DEHP was mainly adsorbed from water to sediments. These findings clarify the multimedia distribution and interfacial migration behaviors of PAEs in a plateau lake, offering scientific support for understanding their ecological risks and environmental fate in enclosed lake systems.