title: Both Phosphorus Fertilizers and Indigenous Bacteria Enhance Arsenic Release into Groundwater in Arsenic-Contaminated Aquifers.
abstract: Arsenic (As) is a human carcinogen, and arsenic contamination in groundwater is a worldwide public health concern. Arsenic-affected areas are found in many places but are reported mostly in agricultural farmlands, yet the interaction of fertilizers, microorganisms, and arsenic mobilization in arsenic-contaminated aquifers remains uncharacterized. This study investigates the effects of fertilizers and bacteria on the mobilization of arsenic in two arsenic-contaminated aquifers. We performed microcosm experiments using arsenic-contaminated sediments and amended with inorganic nitrogenous or phosphorus fertilizers for 1 and 4 months under aerobic and anaerobic conditions. The results show that microcosms amended with 100 mg/L phosphorus fertilizers (dipotassium phosphate), but not nitrogenous fertilizers (ammonium sulfate), significantly increase aqueous As(III) release in arsenic-contaminated sediments under anaerobic condition. We also show that concentrations of iron, manganese, potassium, sodium, calcium, and magnesium are increased in the aqueous phase and that the addition of dipotassium phosphate causes a further increase in aqueous iron, potassium, and sodium, suggesting that multiple metal elements may take part in the arsenic release process. Furthermore, microbial analysis indicates that the dominant microbial phylum is shifted from α-proteobacteria to β- and γ-proteobacteria when the As(III) is increased and phosphate is added in the aquifer. Our results provide evidence that both phosphorus fertilizers and microorganisms can mediate the release of arsenic to groundwater in arsenic-contaminated sediments under anaerobic condition. Our study suggests that agricultural activity such as the use of fertilizers and monitoring phosphate concentration in groundwater should be taken into consideration for the management of arsenic in groundwater.
authors.affiliation: Department of Bioenvironmental Systems Engineering, National Taiwan University , No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan.
authors.forename: Tzu-Yu
authors.initials: TY
authors.lastname: Lin
authors.affiliation: Department of Bioenvironmental Systems Engineering, National Taiwan University , No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan.
authors.forename: Chia-Cheng
authors.initials: CC
authors.lastname: Wei
authors.affiliation: Department of Bioenvironmental Systems Engineering, National Taiwan University , No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan.
authors.forename: Chi-Wei
authors.initials: CW
authors.lastname: Huang
authors.affiliation: Department of Bioenvironmental Systems Engineering, National Taiwan University , No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan.
authors.forename: Chun-Han
authors.initials: CH
authors.lastname: Chang
authors.affiliation: Forest Chemistry Division, Taiwan Forestry Research Institute , 53 Nanhai Road, Taipei 100, Taiwan.
authors.forename: Fu-Lan
authors.initials: FL
authors.lastname: Hsu
authors.affiliation: Department of Bioenvironmental Systems Engineering, National Taiwan University , No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan.
authors.forename: Vivian Hsiu-Chuan
authors.initials: VH
authors.lastname: Liao
mesh_terms: D000383:Agriculture; D001151:Arsenic / Q000032:analysis*; D001419:Bacteria / Q000378:metabolism*; D005308:Fertilizers / Q000032:analysis*; D019015:Geologic Sediments / Q000032:analysis; D060587:Groundwater / Q000737:chemistry*; D008670:Metals / Q000032:analysis; D010758:Phosphorus / Q000032:analysis*; D012987:Soil / Q000737:chemistry; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D005308:Fertilizers; D008670:Metals; D012987:Soil; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D001151:Arsenic
keywords: agricultural activity; arsenic; groundwater; microorganisms; phosphate fertilizers; sediment