Effects of arsenic on bioelectricity output and anode microbial community of soil microbial fuel cells in arsenic-petroleum hydrocarbon-contaminated soils

Background Hydrocarbon production is a potential emission source of arsenic. Sites contaminated by arsenic and hydrocarbons are common but have received little attention. This study selects soil polluted by petroleum hydrocarbons and arsenic as a matrix to construct soil microbial fuel cells (SMFCs), investigates the effect of arsenic on the performance of the SMFCs, so as to provide basic data for the remediation design of such sites, and thus provides a new technical option for the remediation of organic-inorganic-contaminated sites. Results Five groups of SMFCs were tested under different soil arsenic concentrations. When soil arsenic concentration increased from 4.72 to 842.12 mg kg(-1), the maximum power density of the SMFCs decreased from 11.3 to 1.8 mW m(-2), while the internal resistance increased from 871.4 to 1322.1 omega. The anode microbial community of the SMFCs aggregated arsenic-resistant and electric adaptive microbes due to increased arsenic stress, resulting in a decrease in community abundance but an increase in community evenness, which accordingly contributed to the observed change in bioelectricity output. SMFCs did drive the migration of arsenic in soil to the cathode, and this effect decreased with increasing soil arsenic concentration. Conclusions With an increase of arsenic, the bioelectricity output of SMFCs was significantly inhibited and the abundance of anode microbial communities decreased. SMFCs did have a cathodic driving effect on arsenic in the soil. This study has practical significance for improving SMFCs in metal/metalloid-polluted sites, which can provide an optional process for the remediation of organic-metal/metalloid-polluted sites. (c) 2022 Society of Chemical Industry (SCI).

Automated summary

This study investigates the effect of arsenic on the performance of soil microbial fuel cells (SMFCs) constructed using soil polluted by petroleum hydrocarbons and arsenic. The results show that increasing soil arsenic concentration leads to a decrease in maximum power density and an increase in internal resistance of the SMFCs. The microbial community on the anode adapts to increased arsenic stress, resulting in changes in community abundance and bioelectricity output. SMFCs also drive the migration of arsenic to the cathode, with this effect decreasing at higher soil arsenic concentrations.