Effects of perfluoroalkyl acids on environmental microbial community

Environmental pollutants are found to potently disturb the dynamics of environmental microbiota. However, whether and how perfluoroalkyl acids (PFAAs) will affect microbial community remain largely unknown. In this study, effects of PFAAs on environmental microbiota of various habitats (i.e., sediment, surface seawater and teleost intestines) were investigated. A shelf cruise was launched in 2017 to sample surface seawater and sediment around PRD region. Concentrations of total PFAAs in seawater were measured between 131–1563 pg L⁻¹ , among which PFOS, PFOA, PFHpA, PFBA, PFBS, PFHxS, PFPeA and PFHxA homologues were ubiquitous. In sediment, total PFAA concentrations were 24.2–181.4 pg/g dry weight and PFOS was the dominant homologue. Compared to previous monitoring data, PRD PFAA pollution in current cruise showed a remarkable decrease, indicating an effective management of PFAA manufacture and uses. Microbial community in seawater and sediment was also profiled using 16S amplicon sequencing. Correlation analysis between environmental factors and microbiota found that PFAA pollutants were positively and significantly associated with Fluviicola, Nitrosopumilus, Limnohabitans, Sediminibacterium, C39 and Polynucleobacter genera in seawater, while dissolved oxygen was the major shaper of sedimentary microbiota. However, whether PFAAs pose a direct effect on microbial community needs a large-scale long-term monitoring.
Following the phase-out of PFOS, PFBS is an emerging PFAA pollutant of concern. In this study, marine medaka were exposed to environmentally realistic concentrations of PFBS (0, 1, 3 and 10 µg/L) for an entire life-cycle. Then, F0 adult medaka were depurated in clean water for two months. F1 offspring were cultured in clean seawater until sexual maturity. Effects of PFBS on gut health from F0-exposed, F0-depurated and F1 medaka were examined. Although PFBS accumulation was only detected in F0 intestines, results showed that PFBS exposure significantly impaired a series of physiological activities in both F0 and F1 generations, including gut-brain neurotransmission, gut epithelial barrier integrity, inflammatory induction, endotoxin secretion, oxidative stress and hepatic lipid metabolism. Clustering analysis and PCA based on bacterial community composition and abundances found that PFBS had a dramatic and long-lasting disruption on intestinal microbiota, which could not be restored after depuration. Furthermore, gut microbiota of F1 medaka from exposure groups showed a high similarity to that of F0 parents, highlighting a transgenerational dysbiosis despite that F1 offspring was cultured in clean seawater.
Overall, results of current study underlie the disruptive effects of PFAA pollutants on environmental microbial community structure, especially in intestinal environments. Future research is warranted to elucidate the interactive modes between pollutants and microbiota as well as the biological meaning to host health. Copyright © 2019 ICMPE-9.