Co-occurrence of PFASs, heavy metals and PAHs and their composite impacts on microbial consortium in soil: A field study

Abstract

This is the first study to report the co-occurrence of per- and polyfluoroalkyl substances (PFASs), heavy metals and polycyclic aromatic hydrocarbons (PAHs) and their impacts on the native microbial consortium in soil due to the long-term exposure. PFASs, heavy metals and PAHs were detected in soil samples collected at 2–6 m below the ground surface at different sampling locations in a steel-making factory. The total concentrations of PFASs varied from 6.55 to 19.79 ng/g, and perfluorooctane sulfonate (PFOS), perfluorobutane sulfonate and 6:2 chlorinated polyfluorinated ether sulfonic acid (alternative of PFOS) were the predominant PFASs. The concentrations of arsenic, cadmium and lead were detected in the ranges of 4.40–1270.00, 0.01–8.67 and 18.00–647.00 mg/kg, respectively, and the total PAHs was detected in the range of 1.02–131.60 mg/kg. The long-term exposure to PFASs, heavy metals and PAHs mixed contaminants led to lower richness and diversity of microbial communities in soil. The soil bacterial communities were mainly composed of Pseudomonas, norank_p_GAL15, Leptothrix, norank_o_Rokubacteriales and Acinetobacter. Correlations between environmental factors and the microbial community indicated that cation exchange capacity and total phosphorus were two key factors in shaping up the compositions of native microbial community. Furthermore, Arthrobacter, Leptothrix and Sphingobium were found significantly positively correlated with PFASs concentrations, indicating that these genera could tolerate the stress exerted by PFASs, along with the stress imposed due to the presence of heavy metals or/and PAHs.