Factors affecting arsenic mobilization for arsenic-contaminated groundwater in Blackfoot disease endemic region in Taiwan
Date Issued
2014
Date
2014
Author(s)
Lin, Tzu-Yu
Abstract
Arsenic (As) contamination of groundwater is a worldwide public health concern. Arsenic affected areas in Taiwan were reported mostly in farmland, yet the factors of arsenic mobilization in aquifer remain uncharacterized. This study investigated microbial communities between sediments from the blackfoot disease (BFD) and non-BFD endemic area. The results showed that after 2 months incubation, the microbial community showed significantly different in the BFD and non-BFD endemic area. In addition, the effects of fertilizers and microorganisms on arsenic mobilization in the sediments of the BFD endemic area were examined. Microcosm experiments were performed amending with inorganic nitrogenous or phosphorus fertilizers for 2 and 4 months under aerobic and anaerobic conditions. The results showed that microcosms amended with 25 and 100 mg/L phosphorus fertilizers (dipotassium phosphate) showed significant increases in arsenic concentrations in aqueous phases, with an arsenite (As(III)) concentration increase from 66.4 ± 4.6 μg/L (original non-sterilized sediments) to 81.6 ± 8.6 (25 mg/L dipotassium phosphate, non-sterilized sediments) and 110.5 ± 6.0 μg/L (100 mg/L dipotassium phosphate, non-sterilized sediments) under anaerobic condition. However, the addition of nitrogenous fertilizers (ammonium sulfate) showed little effect on the arsenic mobility. Moreover, concentrations of iron, manganese, potassium, sodium, calcium, and magnesium were increased in the aqueous amended with dipotassium phosphate, suggesting that multiple metal elements may take part in the arsenic release process. Furthermore, microbial analysis indicated that the dominant microbial phylum was shifted from α-Proteobacteria to β- and γ-Proteobacteria when the As(III) was increased and phosphate was added in the aquifer. Our results provide evidence that both phosphorus fertilizers and microorganisms can mediate the release of sedimentary arsenic to groundwater in the BFD region, suggesting that agricultural activity such as usage of fertilizers should be taken into consideration.
Subjects
arsenic
mobilization
blackfoot disease
fertilizers
groundwater
microbial community
SDGs
Type
thesis
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