Using Plants to Immobilize and Stabilize Arsenic in the Soil

12/14/2017

Microscale X-ray fluorescence imaging of a 30 μm thick P. juliflora root thin section from a plant grown at the IKMHSS tailings amended with 15% compost and lime for one year

Microscale X-ray fluorescence imaging of a 30 μm thick Prosopis juliflora root thin section from a plant grown in tailings from the Iron King Mine and Humboldt Smelter Superfund site amended with 15% compost and lime for one year. The tricolor plot represents an overlay of Fe, As(V), and As(III)−S in a 10:1:1 ratio of intensity scales. [Reprinted with permission from Hammond et al. 2018. DOI:10.1021/acs.est.7b04363. Copyright 2018 American Chemical Society.]

Scientific Achievement

Prosopis juliflora plant roots were shown to use a combination of two mechanisms to scavenge and immobilize arsenic from mine tailings.

Significance and Impact

Phytostabilization can be a cost-effective and long-term bioremediation technique for the detoxification of arsenic-rich mine tailings.

Research Details

  • Micro-XANES imaging at SSRL and NSLS-II was used to resolve arsenic, iron, and sulfur spatial distribution and speciation in plant tissues.
  • Results revealed two distinct mechanisms of arsenic detoxification via (1) As(V) bound to ferric sulfate plaques on root surfaces and (2) As(III) complexes in root vacuoles.

References

Hammond, C. M., et al. 2018. “Mechanisms of Arsenic Sequestration by Prosopis juliflora During the Phytostabilization of Metalliferous Mine Tailing,” Environmental Science & Technology 52, 1156−64. [DOI:10.1021/acs.est.7b04363]