Perfluorooctane sulfonate in water and sediment from the Yangtze Estuary and coastal waters: Occurrence, partitioning and diffusion behavior and risk assessment

Abstract

As an emerging environmental contaminant, perfluorooctane sulfonate (PFOS) has attracted increasing attention. This study investigated the occurrence, partitioning and diffusion behavior, and risk assessment of PFOS in 19 water and sediment samples collected from the Yangtze Estuary and coastal waters in March 2022. The concentration of PFOS is 0.053–0.95 ng L−1 in water and 0.031–0.18 ng g−1 (dw) in sediments, demonstrating a transparent concentration gradient from inshore to offshore sites. The fugacity fraction model results showed that, except for a few sites, the diffusion trend of PFOS was from sediment into the water. Correlation and response coefficient (RC) analyses revealed a significant relationship between sediment organic carbon (TOC) and PFOS partitioning. According to the sediments-water partitioning coefficient Kd, in estuarine areas, seawater salinity tended to allocate PFOS to sediments. Ecological risk assessment findings revealed that PFOS posed a low to moderate risk in sediment rather than a problem in water.