The Role of Low-Molecular-Weight Organic Carbons in Facilitating the Mobilization and Biotransformation of As(V)/Fe(III) from a Realgar Tailing Mine Soil

ABSTRACT

Several low-molecular-weight organic carbon (LMWOC) compounds (acetate, propionate, butyrate, lactate, and glucose) were added to flooded arsenic-rich tailing mine soil to investigate their effect to the mobilization of As/Fe and potential shift of microbial community. A promoting effect to the mobilization and biotransformation of As(V)/Fe(III) in the soils resulting from the supplementation with LMWOCs substrate was indicated compared to the biotic microcosm amended with deionized water alone. During 38-day biotic incubation, more than 2100 μg/L of As(III) and 4.2 mg/L of Fe(II) levels were released from the soils amended with LMWOCs substrates, compared to the levels of As(III) and Fe(II) (less 35 μg/L and 1.82 mg/L) derived from the biotic supplementation with deionized water alone. PCR-DGGE indicated that several LMWOCs-responded bacteria were mostly related to Firmicutes and Proteobacteria. Moreover, a negligible impact on the abundance of Fe(III)-reducing family Geobacteraceae was indicated in the LMWOCs-amended soils. However, an increased abundance of sulfate-reducing bacteria but a decreased abundance of arsenate-respiring bacteria were indicated upon the soils supplemented with acetate alone, compared with other LMWOC amendments. DNA-stable isotope probing analysis demonstrated that the dual roles of acetate was not only served as an electron donor for biotransformation of As(V)/Fe(III) in soil, but also assimilated as a powerful energy source to promote the growth of sulfate-reducing bacteria. The findings suggest that there are specific bacteria that preferentially respond to the additions of LMWOC for controlling the biochemical cycle process of As/Fe in soils.

KEYWORDS:

• Arsenic
• iron
• low-molecular-weight organic carbons
• microbial community
• soil

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (41571449, 41271260 and 41301346), the National Basic Research Program of China (2013CB733505), the Fundamental Research Funds for the Central Universities of China (20720160083) and the Project of Educational Scientific Research of Junior Teacher of Fujian Province of China (JAT170831), and the Open Fund of the Fujian Provincial Key Laboratory of Resource and Environmental Minitoring & Sustainable Management and Utilization of China (ZD1702).