Occurrence, distribution, and ecological risks of phthalate esters in the seawater and sediment of Changjiang River Estuary and its adjacent area.

A total of 133 seawater samples and 17 sediment samples were collected from 81 sampling sites in the Changjiang River Estuary and its adjacent area and were analyzed for 16 phthalate esters (PAEs). The Σ16 PAE concentrations in the seawater and sediment samples ranged from 180.3ng·L-1 to 3421ng·L-1 and from 0.48μg·g-1 to 29.94μg·g-1dry weight (dw), respectively, with mean values of 943.6ng·L-1 and 12.88μg·g-1. The distribution of ∑16PAE concentrations in the water column showed that PAE concentrations in the bottom samples were higher than those in the surface samples (except the transect C located inside the Changjiang River Estuary), with the maxima appearing in the bottom layer at the offshore stations. Among the 16 PAEs, di (2-ethylhexyl) phthalate (DEHP), diisobutyl phthalate (DiBP), and dibutyl phthalate (DnBP) dominated the PAEs, with 25.1%, 21.1%, and 18.9% of the Σ16PAEs in seawater, respectively. The comparison of ∑16PAEs and salinities in transects C and A6 suggested that the Changjiang River runoff was an important driving factor influencing the distribution of PAEs. DEHP concentrations in water samples and DEHP and DnBP concentrations in sediment samples exceeded the environmental risk levels (ERL), indicating their potential hazard to the ocean environment.