TY - JOUR
T1 - Mechanisms of Arsenic Sequestration by Prosopis juliflora during the Phytostabilization of Metalliferous Mine Tailings
AU - Hammond, Corin M.
AU - Root, Robert A.
AU - Maier, Raina M.
AU - Chorover, Jon
N1 - Funding Information:
This research was supported by NIEHS Superfund Research Program grant no. 2 P42 ES04940. We thank Steven Schuchardt, president of North American Industries for providing access to the IKMHSS site and for help with irrigation and the weather station. Portions of this research were carried out at Stanford Synchrotron Radiation Laboratory, a National User Facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences. This research performed on NSLS-II proposal no. 300145 used the SRX beamline of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DESC0012704. Special thanks go to Scott White for extensive work in establishing and maintaining the field site and greenhouse study and for supervising all field-sampling efforts. We recognize Juliana Gil-Loaiza, who contributed invaluable assistance in organizing annual field sampling, and Mon Bejar and Deseree Carrillo for mesquite sample processing. We thank Guilherme Dinali for helping to set up the greenhouse experiment and all of the volunteer students from Environmental Microbiology, Environmental Biochemistry, and Contaminant Transport Laboratories at the University of Arizona for their help during field-sampling trips from 2010 to 2015. Gratitude is expressed to Sam Webb for his expert advice on μXRF and arsenic storage in plants and to Mary Kay Amistadi, Kelsie Lasharr, and Shawn Pedron for ICP-MS analyses of Fe, As, and S content of samples performed at the Arizona Laboratory for Emerging Contaminants (ALEC) at the University of Arizona. The views of authors do not necessarily represent those of the NIEHS or the NIH.
Funding Information:
This research was supported by NIEHS Superfund Research Program grant no. 2 P42 ES04940. We thank Steven Schuchardt, president of North American Industries for providing access to the IKMHSS site and for help with irrigation and the weather station. Portions of this research were carried out at Stanford Synchrotron Radiation Laboratory a National User Facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences. This research performed on NSLS-II proposal no. 300145 used the SRX beamline of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. Special thanks go to Scott White for extensive work in establishing and maintaining the field site and greenhouse study and for supervising all field-sampling efforts. We recognize Juliana Gil-Loaiza, who contributed invaluable assistance in organizing annual field sampling, and Mon Bejar and Deseree Carrillo for mesquite sample processing. We thank Guilherme Dinali for helping to set up the greenhouse experiment and all of the volunteer students from Environmental Microbiology Environmental Biochemistry, and Contaminant Transport Laboratories at the University of Arizona for their help during field-sampling trips from 2010 to 2015. Gratitude is expressed to Sam Webb for his expert advice on μXRF and arsenic storage in plants and to Mary Kay Amistadi, Kelsie Lasharr, and Shawn Pedron for ICP-MS analyses of Fe, As, and S content of samples performed at the Arizona Laboratory for Emerging Contaminants (ALEC) at the University of Arizona. The views of authors do not necessarily represent those of the NIEHS or the NIH.
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2018/2/6
Y1 - 2018/2/6
N2 - Phytostabilization is a cost-effective long-term bioremediation technique for the immobilization of metalliferous mine tailings. However, the biogeochemical processes affecting metal(loid) molecular stabilization and mobility in the root zone remain poorly resolved. The roots of Prosopis juliflora grown for up to 36 months in compost-amended pyritic mine tailings from a federal Superfund site were investigated by microscale and bulk synchrotron X-ray absorption spectroscopy (XAS) and multiple energy micro-X-ray fluorescence imaging to determine iron, arsenic, and sulfur speciation, abundance, and spatial distribution. Whereas ferrihydrite-bound As(V) species predominated in the initial bulk mine tailings, the rhizosphere speciation of arsenic was distinctly different. Root-associated As(V) was immobilized on the root epidermis bound to ferric sulfate precipitates and within root vacuoles as trivalent As(III)-(SR)3 tris-thiolate complexes. Molar Fe-to-As ratios of root epidermis tissue were two times higher than the 15% compost-amended bulk tailings growth medium. Rhizoplane-associated ferric sulfate phases that showed a high capacity to scavenge As(V) were dissimilar from the bulk-tailings mineralogy as shown by XAS and X-ray diffraction, indicating a root-surface mechanism for their formation or accumulation.
AB - Phytostabilization is a cost-effective long-term bioremediation technique for the immobilization of metalliferous mine tailings. However, the biogeochemical processes affecting metal(loid) molecular stabilization and mobility in the root zone remain poorly resolved. The roots of Prosopis juliflora grown for up to 36 months in compost-amended pyritic mine tailings from a federal Superfund site were investigated by microscale and bulk synchrotron X-ray absorption spectroscopy (XAS) and multiple energy micro-X-ray fluorescence imaging to determine iron, arsenic, and sulfur speciation, abundance, and spatial distribution. Whereas ferrihydrite-bound As(V) species predominated in the initial bulk mine tailings, the rhizosphere speciation of arsenic was distinctly different. Root-associated As(V) was immobilized on the root epidermis bound to ferric sulfate precipitates and within root vacuoles as trivalent As(III)-(SR)3 tris-thiolate complexes. Molar Fe-to-As ratios of root epidermis tissue were two times higher than the 15% compost-amended bulk tailings growth medium. Rhizoplane-associated ferric sulfate phases that showed a high capacity to scavenge As(V) were dissimilar from the bulk-tailings mineralogy as shown by XAS and X-ray diffraction, indicating a root-surface mechanism for their formation or accumulation.
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U2 - 10.1021/acs.est.7b04363
DO - 10.1021/acs.est.7b04363
M3 - Article
C2 - 29241010
AN - SCOPUS:85041454593
VL - 52
SP - 1156
EP - 1164
JO - Environmental Science & Technology
JF - Environmental Science & Technology
SN - 0013-936X
IS - 3
ER -