Co-occurrence of per- and polyfluoroalkyl substances, heavy metals and polycyclic aromatic hydrocarbons 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. The 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-1, with perfluorooctane sulfonate (PFOS), perfluorobutane sulfonate, and 6:2 chlorinated polyfluorinated ether sulfonate (alternative of PFOS) being the predominant PFASs. The concentrations of arsenic, cadmium, and lead were detected in the ranges of 4.40–1 270.00, 0.01–8.67, and 18.00–647.00 mg kg-1, respectively, and the concentration of total PAHs was detected in the range of 1.02–131.60 mg kg-1. The long-term exposure to mixed contaminants of PFASs, heavy metals, and PAHs 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 soil environmental factors and microbial communities indicated that cation exchange capacity and total phosphorus were two key factors in shaping the composition of native microbial communities. Furthermore, Arthrobacter, Leptothrix, and Sphingobium were found to be significantly positively correlated with PFAS 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.