title: Microbial mineral weathering for nutrient acquisition releases arsenic.
abstract: Tens of millions of people in Southeast Asia drink groundwater contaminated with naturally occurring arsenic. How arsenic is released from the sediment into the water remains poorly understood. Here, we show in laboratory experiments that phosphate-limited cells of Burkholderia fungorum mobilize ancillary arsenic from apatite. We hypothesize that arsenic mobilization is a by-product of mineral weathering for nutrient acquisition. The released arsenic does not undergo a redox transformation but appears to be solubilized from the apatite mineral lattice during weathering. Analysis of apatite from the source area in the Himalayan basin indicates the presence of elevated levels of arsenic, with an average concentration of 210 mg/kg. The rate of arsenic release is independent of the initial dissolved arsenic concentration and occurs at phosphate levels observed in Bangladesh aquifers. We also demonstrate the presence of the microbial phenotype that releases arsenic from apatite in Bangladesh aquifer sediments and groundwater. These results suggest that microbial mineral weathering for nutrient acquisition could be an important mechanism for arsenic mobilization.
authors.affiliation: Environmental Science Department, Barnard College, New York, New York 10027, USA. bmaillou@barnard.edu
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Mailloux
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Alexandrova
authors.forename: Alison R
authors.initials: AR
authors.lastname: Keimowitz
authors.forename: Karen
authors.initials: K
authors.lastname: Wovkulich
authors.forename: Greg A
authors.initials: GA
authors.lastname: Freyer
authors.forename: Michael
authors.initials: M
authors.lastname: Herron
authors.forename: John F
authors.initials: JF
authors.lastname: Stolz
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Kenna
authors.forename: Thomas
authors.initials: T
authors.lastname: Pichler
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Polizzotto
authors.forename: Hailiang
authors.initials: H
authors.lastname: Dong
authors.forename: Michael
authors.initials: M
authors.lastname: Bishop
authors.forename: Peter S K
authors.initials: PS
authors.lastname: Knappett
mesh_terms: D001031:Apatites / Q000378:metabolism*; D001151:Arsenic / Q000032:analysis*; D001459:Bangladesh; D019117:Burkholderia / Q000378:metabolism*; D019015:Geologic Sediments / Q000382:microbiology*; D006801:Humans; D014867:Water / Q000032:analysis*
chemical_list: D001031:Apatites; D014867:Water; D001151:Arsenic