Short- and long-chain perfluoroalkyl substances in the water, suspended particulate matter, and surface sediment of a turbid river

Abstract

Perfluoroalkyl substances (PFASs) have attracted attentions all around the world. However, little is known about their distribution among water, suspended particulate matter (SPM), and sediment phases in rivers, especially for the short-chain PFASs. In this work, the Yellow River, the largest turbid river in the world, was selected as a case to study eleven kinds of PFASs in the three phases of rivers. These PFASs included C4–C12 perfluorinated carboxylates (PFCAs), perfluorobutyl sulfonate (PFBS), and perfluorooctansulfonate (PFOS), among which C4–C7 PFCAs and PFBS belong to short-chain PFASs, while C8–C12 PFCAs and PFOS belong to long-chain PFASs. The results showed that the total PFAS concentration ranged from 44.7ngL−1 to 1.52μgL−1 in the water, from 8.19 to 17.4ngg−1 in the sediment, and from 3.44 to 14.7ngg−1 in the SPM. Short-chain PFASs predominated in the water and could reach up to 88.8% of the total PFAS concentration in water, while long-chain PFASs prevailed in the sediment and SPM. The PFAS concentration in SPM showed a significant negative correlation with SPM concentration in river water (p<0.01). The distribution coefficients (Kd) of PFASs between sediment/SPM and water increased with their chain length and there was a positive correlation between logKd and logKow (octanol-water partition coefficients). The total annual flux of all the eleven PFASs was estimated at 3.88tons for the Yellow River into the Bohai Sea, among which the PFOA flux was the highest (0.90tons). The widely occurrence and high concentrations of short-chain PFASs in the Yellow River indicates the shift of manufacturing focus of perfluoroalkyl chemicals from traditional long-chain ones to short-chain ones. Further studies should be conducted to evaluate the eco-environmental risks of these short-chain PFASs in water environments.