Arsenic fractionation in mine spoils 10 years after aided phytostabilization

Environ Pollut. 2012 Jul:166:82-8. doi: 10.1016/j.envpol.2012.02.016. Epub 2012 Apr 4.

Abstract

Aided phytostabilization using a combination of compost, zerovalent iron grit and coal fly ash (CZA) amendments and revegetation effectively promoted the biological recovery of mining spoils generated at a gold mine in Portugal. Selective dissolution of spoil samples in combination with solid phase characterization using microbeam X-ray absorption near edge structure (μXANES) spectroscopy and microbeam X-ray fluorescence (μXRF) mapping were used to assess As associations in spoils ten years after CZA treatment. The results show that As preferentially associates with poorly crystalline Fe-oxyhydroxides as opposed to crystalline Fe-(oxyhydr)oxide phases. The crystalline Fe(III)-phases dominated in the treated spoil and exceeded those of the untreated spoil three-fold, but only 2.6-6.8% of total As was associated with this fraction. Correlation maps of As:Fe reveal that As in the CZA-treated spoils is primarily contained in surface coatings as precipitates and sorbates. Arsenic binding with poorly crystalline Fe-oxyhydroxides did not inhibit As uptake by plants.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Arsenic / analysis
  • Arsenic / chemistry*
  • Biodegradation, Environmental
  • Chemical Fractionation
  • Coal Ash / chemistry
  • Environmental Monitoring
  • Environmental Restoration and Remediation / methods*
  • Iron / chemistry
  • Mining*
  • Plant Development*
  • Plants / metabolism
  • Portugal
  • Soil Pollutants / analysis
  • Soil Pollutants / chemistry*

Substances

  • Coal Ash
  • Soil Pollutants
  • Iron
  • Arsenic