Occurrence and distribution of poly-and perfluoroalkyl substances (PFASs) in a surface flow constructed wetland

The occurrence and distribution of poly- and perfluoroalkyl substances (PFASs) in water and sediment cores from a surface flow wetland ecosystem (New York State, USA), as well as their relationships with microbial communities were investigated. The total concentrations of PFASs (& sum;PFASs) in aqueous phase were in the range of 27.6-94.2 ng L-1, while the values in the sediment varied from 2.1 ng g-1 to 6.6 ng g-1. In the aqueous phase, perfluorooctanoic acid (PFOA) (9.4-28.8 ng L-1) was the most predominant compound, followed by perfluorooctane sulfonic acid (PFOS) (5.8-15.4 ng L-1). PFOS was dominant in sediment, with an average concentration of 2.6 ng g-1, followed by PFOA (0.5 ng g-1) and perfluorohexanesulfonate (PFHxS) (0.1 ng g-1). Sediment-water distribution coefficients (log Kd) were in the range 0.7-2.5, and increased with the increase in perfluoroalkyl chain length. Carbon-chain length was a primary factor governing the distribution and behavior of PFASs in the aquatic environment. A positive correlation between the average log KOC and the chain length of perfluoroalkyl (p < 0.01) was observed. Illumina high-throughput sequencing technology was applied to profile the composition of bacterial community in the sediments. At the phylum level, the predominant (> 1.0%) bacteria included Proteobacteria (63.67%), Armatimonadetes (12.98%), Actinobacteria (9.57%), Bacteroidetes (5.08%), and Verrucomicrobia (1.1%). Variations in microbial communities among sampling stations associated with PFAS concentrations were mainly due to the differences in abundances of Candidatus pl & Oslash;tophila, Fluviicola, Methylobacillus, Limnohabitans and Flavobacterium. Results of this study would be beneficial to understanding the distribution and bioaccumulation of PFASs in environmental matrix and provide some useful information for controlling PFASs contaminations in wetland ecosystems.

Automated summary

The study investigated the occurrence and distribution of PFASs in a surface flow wetland ecosystem in New York State, USA, and their relationships with microbial communities. The main PFASs detected were PFOS and PFOA, with carbon-chain length being a primary factor influencing their behavior in the aquatic environment. Microbial community variations were associated with PFAS concentrations, with certain bacteria species being more abundant in areas with higher PFAS levels.