Phthalate esters and microplastics in sediments of Haomeiliao Wetland, Southwestern Taiwan: Occurrence, spatial...

Phthalate esters (PAEs) and microplastics (MPs) are emerging contaminants in aquatic environments. However, their co-occurrence in wetland sediments remains poorly understood. This study aimed to quantify PAE concentrations and MP abundance in Haomeiliao Wetland and comprehensively assess their spatial distribution and potential correlations. A total of 14 sediment samples were collected across the study area. MPs were characterized and analyzed using a stereomicroscope and micro-Fourier transform infrared spectrometer (μFTIR), respectively. While PAEs were quantified using gas chromatography-mass spectrometry (GC-MS). The total PAE concentrations varied from 287.9 ± 161.2 ng/g to 1688.8 ± 610.9 ng/g, with DiNP and DiDP being the primary contributors to the total PAE load. The abundance of MP ranged from 30 to 390 MPs/kg, predominantly composed of polypropylene (PP; 51%) and polyester (PES; 22%) polymers. Despite MPs being known carriers of hydrophobic contaminants, no significant correlation was observed between MP abundance and the total PAE concentration. This suggests that MP-associated PAE transport is not a major contributor to sediment PAE levels, and may have originated from other predominant sources. These findings provide crucial baseline data for pollution mitigation in wetland ecosystems.