Arsenic Speciation: Involvement in Evaluation of Environmental Impact Caused by Mine Wastes

摘要: Since large areas have been contaminated by arsenic-rich industrial and mining by-products in several countries, knowledge of arsenic (As) behavior soils water is major concern for reclamation polluted sites evaluation environmental risk. Chemi's tailings (France) contains average concentrations up to 7,000 mg kg{sup {minus}1} As was listed the authority as an important potentially pollutant site. Because speciation determines its mobility, it investigated surface ground waters site a study solid As-bearing phase performed on suspended particulate material (SPM). Results sequential extraction, carried out SPM collected drainage waters, show that most total extracted (78%) Fe (77%) bound iron hydrous oxide phase, which determined be lepidocrocite ({gamma}-FeOOH) x-ray diffraction infrared spectrometry. Particulate >220 times more concentrated than dissolved As. Conditions stability (<0.45 {micro}m) arsenite [As(III)] arsenate [As(V)] are discussed basis thermodynamical data field measurements pH redox potentials. The theoretical As(V) corresponds association between material, amounts metalloidmore » released solution when As-rich particles come from oxidized moderately reduced conditions. These results evaluating, modeling, rehabilitating As-polluted sites.« less