Distribution and ecotoxicological state of phthalate esters in the sea-surface microlayer, seawater and sediment of the Bohai Sea and the Yellow Sea.

The spatial distribution, chemical composition and ecological risk of 16 phthalate esters (PAEs) were investigated in the sea-surface microlayer (SML), seawater and sediment samples of the Bohai Sea (BS) and the Yellow Sea (YS). The concentration levels of the ΣPAEs spanned a range of 449-13441 ng L-1 in the SML, 453-5108 ng L-1 in seawater, and 1.24-15.8 mg kg-1 in the sediment samples, respectively, with diisobutyl phthalate (DiBP), di-n-butyl phthalate (DBP) and di-ethylhexyl phthalate (DEHP) as the dominant PAEs in both the water and sediment samples. The concentrations of ΣPAEs in the BS were higher than those in the YS. The vertical distribution of ΣPAEs in the water column showed that the concentrations were higher in the surface waters, but decreased slightly with depth, and started to increase at the bottom. Additionally, PAEs were significantly enriched in the SML, with an average enrichment factor of 1.46. The ecological risk of the PAEs was evaluated by the risk quotient (RQ) method, which indicated that DEHP posed a high risk to aquatic organisms in the whole water-phase, while the RQ values of DBP and DiBP reached a high risk levels in sedimentary environment.