WANG Song, CHEN Jiachang, DAI Zhenyu, ZHANG Qiyi, LI Yunlong, ZHANG Baogang

( School of Water Resources and Environment, China University of Geosciences Beijing, Key Laboratory of Groundwater Circulation and Evolution, Ministry of Education, Beijing 100083, China)

Abstract: Thallium (Tl), a bio-accumulative toxic heavy metal, usually presents as Tl(I) in the natural environment. Once entered into water, soil and sediment, Tl may cause serious environment pollutions. The study investigated aerobically microbial treatments to remediate Tl-contaminated groundwater, the initial concentration of Tl(I) was set as 100 μg/L and sodium acetate was chosen as the carbon source, after 6 day remediation, the total Tl removal efficiency reached 63.5%. Total Tl removal efficiency correlated negatively with the initial Tl(I) concentration, and varied as pH was increased. According to the high-throughput 16S rRNA gene sequencing analyses, Tl(I) resistance and Tl(I) oxidation bacteria, such as Stenotrophomonas, Acidovorax, Rhodococcus, etc., were detected in the system, these bacteria oxidized Tl(I) and precipitated the oxides in-situ. This study provides theoretical foundation for microbial remediation of Tl-contaminated groundwater and the new perspective on applying microbial remediation to remove other heavy metals from contaminated groundwater.

Key words: microbial remediation; thallium; groundwater; high-throughput sequencing

EARTH AND ENVIRONMENT Vol.46, No.3, Tot No.323, 2018, Page 282-287