Pollution characteristics, spatial variation, and ecological risks of phthalate esters in sediment from northern coastal regions of Vietnam

Abstract

Phthalate esters (PAEs) are synthetic plasticizers extensively used in industrial and domestic applications. As ubiquitous emerging contaminants, their presence in the marine environment has raised significant concerns due to their endocrine-disrupting properties and associated ecological and human health risks. Despite growing awareness, the distribution and potential impacts of PAEs in tropical estuarine and coastal ecosystems in Vietnam remain poorly documented. This study investigated the occurrence, spatial distribution, and ecological risks of 10 PAEs in sediment samples collected from 7 coastal regions in northern Vietnam. PAEs were detected in all sediments with the total concentrations of 10 PAEs (Σ₁₀PAEs) in the sediment samples were 120-6013 ng/g-dwt (mean 971 ng/g-dwt), indicating their ubiquitous contamination of the coastal environment. Dibutyl phthalate was the most abundant PAEs in the sediments, accounting for 44.7 % of the total Σ₁₀PAEs concentration, followed by bis(2-ethylhexyl) phthalate (DEHP, 15.2 %) and diisobutyl phthalate (DiBP, 11.2 %), indicating their significant environmental concern. Spatial and seasonal variations of PAEs are likely influenced by site-specific factors and differences in discharge sources at the studied locations. Significant positive correlations were observed among high molecular weight PAEs and among low molecular weight PAEs in the sediments. Tourism and maritime activities, along with urban and industrial discharges are likely the primary sources of PAEs. Notably, DiBP exhibited potential ecological risks to sensitive aquatic organisms in sedimentary environments across all study areas.