The Release Factors and Bioremediation for Arsenic-contaminated Groundwater inBlackfoot Disease Endemic Region in Taiwan

• Main Authors: An-Chieh Kao, 高安潔
• Other Authors: 廖秀娟
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/72550427369174925204

碩士 === 國立臺灣大學 === 生物環境系統工程學研究所 === 100 === The contamination of groundwater with arsenic is a major concern to public health from local to international. Although arsenic groundwater problems in Taiwan had been noted for several years, the factors affecting arsenic release and technology to significantly reduce arsenic level still remain elucidated. In this study, we investigate the effect of agricultural behavior such as fertilizing (ammonium and phosphate) on arsenic mobilization, and isolate an arsenite-oxidizing bacterium As7325 to examine its potential for arsenic bioremediation. The results showed that under anaerobic condition, both phosphate and ammonium caused arsenic release from sediment to groundwater. In addition, the addition of phosphate and ammonium also enhanced the release of ferrous and changed the microbial communities. Bacterial strain As7325, which was isolated from the arsenic-contaminated site, belongs to the genus of Pseudomonas. Strain As7325 is a heterotroph. The optimal temperature for growth was 30oC and the pH was about 7. Strain As7325 could resist high concentration of arsenic with minimum inhibitory concentration at 1 mM for arsenite and over 100 mM for arsenate. Strain As7325 could completely oxidize 30 μM (~ 2250 μg/L) arsenite using in situ groundwater within 1 day under aerobic condition. In addition, lyophilized cell pellet of strain As7325 was used as a biosorbent and could adsorb 6.67 μM (~ 500 μg/L) and 13.33 μM (~ 1000 μg/L) arsenate near 100% at 6-day period. The results showed that strain As7325 has the potential for bioremediation of arsenic.