Effects of Perfluoroheptanoic Acid (PFHpA) on Bacterial Community, Elemental Cycling and ARGs Transmission in Sediment

As a substitute for perfluorooctanoic acid (PFOA), perfluoroheptanoic acid (PFHpA) has been detected in various environments, while its impact on sediment bacteria was unclear. PFHpA exposure altered the whole and the rare bacterial community structure in sediment. Concurrently, PFHpA selectively enriched bacteria involved in C/N/P/S cycling. PFHpA induced intracellular reactive oxygen species (ROS) overproduction, triggering both the antioxidant defense system and the SOS response. PFHpA upregulated functional gene and enzymatic activities involved in C/N/P cycling, while downregulated those involved in S cycling. Based on the co-occurrence patterns between ARGs and MGEs, it might be speculated that HGT potential was increased upon PFHpA exposure. PLS-PM analysis indicated that the rare bacteria had more significant and direct effects on C/N/P/S cycling and transmission of ARGs. These findings will prove useful for understanding the effects of PFHpA on bacterial community, C/N/P/S cycling and transmission of ARGs in sediment.