title: Arsenic fractionation in mine spoils 10 years after aided phytostabilization.
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.
authors.affiliation: Division of Waste Science and Technology, Luleå University of Technology, Luleå SE-97187, Sweden. jurate.kumpiene@ltu.se
authors.forename: Jurate
authors.initials: J
authors.lastname: Kumpiene
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Fitts
authors.forename: Michel
authors.initials: M
authors.lastname: Mench
mesh_terms: D001151:Arsenic / Q000032:analysis / Q000737:chemistry*; D001673:Biodegradation, Environmental; D005591:Chemical Fractionation; D060729:Coal Ash / Q000737:chemistry; D004784:Environmental Monitoring; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007501:Iron / Q000737:chemistry; D008906:Mining; D063245:Plant Development; D010944:Plants / Q000378:metabolism; D011174:Portugal; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*
chemical_list: D060729:Coal Ash; D012989:Soil Pollutants; D007501:Iron; D001151:Arsenic