Metal immobilization in hazardous contaminated minesoils after marble slurry waste application. A field assessment at the Tharsis mining district (Spain).
A one-year field trial was conducted at the abandoned mine site of Tharsis (Spain) in order to assess the potential value of waste sludge generated during the processing of marble stone, as an additive for assisting natural remediation of heavily contaminated acid mine soils. An amendment of 22 cmol(c) of lime per kilogram of soil was applied to raise the pH level from 3.2 to above 6. The amendment application was effective in reducing concentrations of Al, Fe, Mn, sulfate and potentially hazardous trace elements (mainly Cu, Pb, Zn and Cd) in the most labile metal pools (water-soluble and EDTA-extractable fractions). Geochemical equilibrium calculations indicate that sulfate complexes and free metal ions were the dominant aqueous species in the soil solution. Metal coprecipitation with nanocrystalline ferric oxyhydroxides may be the major chemical mechanism of amendment-induced immobilization. The alleviating effect of the soil amendment on the metal bioavailability and phytotoxicity showed promise for assisting natural revegetation of the mine land.
Fernández-Caliani
J C
JC
Departamento de Geología, Facultad de Ciencias Experimentales, Universidad de Huelva, Huelva, Spain. caliani@uhu.es
Barba-Brioso
C
C
D001673:Biodegradation, Environmental; D015386:Hazardous Substances; D008670:Metals / Q000302:isolation & purification*; D008906:Mining; D012722:Sewage / Q000382:microbiology; D012989:Soil Pollutants / Q000302:isolation & purification*; D013030:Spain
D015386:Hazardous Substances; D008670:Metals; D012722:Sewage; D012989:Soil Pollutants