Pollution characteristics, spatial variation, and ecological risks of phthalate esters in seawater and sediment from nine estuaries and their adjacent areas of Hainan Island, China

Phthalate esters (PAEs) are omnipresent emerging contaminants, garnering increasing public attention. Nevertheless, the occurrence and potential risks of PAEs in tropical estuarine and coastal regions remain largely unexplored. This study investigated the occurrence, spatial distribution, and ecological risks of 12 PAEs in seawater and sediment samples collected from 9 estuaries and their adjacent areas around Hainan Island. All the 12 PAEs were examined through solid-phase extraction followed by Gas Chromatography-Mass Spectrometry (GC-MS) analyses. The total concentrations of 12 PAEs (& sum;12PAEs) in the seawater and sediment samples were 25.6-3280.6 ng/L (mean: 721.0 +/- 216.2 ng/L) and 27.0-1503.8 mu g/kg dry weight (dw) (mean: 242.6 +/- 272.6 mu g/kg dw), respectively. Dimethyl phthalate (DMP), Dibutyl phthalate (DBP), Di(2-ethylhexyl) phthalate (DEHP), and Dimethoxyethyl phthalate (DMEP) were identified as primary homologs in both the seawater and the sediments. Additionally, the concentrations of & sum;12PAEs showed a decreasing trend from estuarine sites to offshore sites, indicating that riverine input may be a primary pathway for PAEs pollution in the coastal areas around Hainan Island. Preliminary risk assessment implied that DBP, DEHP, DMEP, and Bis(2-ethoxyethyl) phthalate (DEEP), pose potential threats to sensitive aquatic organisms in this region. Collectively, our findings provide valuable insights for source control and serve as a critical reference for establishing water quality criteria to mitigate PAEs pollution in tropical marine.