title: Mobility of Po and U-isotopes under acid mine drainage conditions: an experimental approach with samples from Río Tinto area (SW Spain).
abstract: Under acid mine drainage (AMD) conditions, the solubilities and mobilities of many elements are vastly different from conditions prevailing in most natural waters. Studies are underway in the Río Tinto area (Iberian Pyrite Belt), in order to understand the behavior and mobility of long-lived U-series radionuclides under AMD conditions. A set of leaching experiments utilizing typical country rocks from the Tinto River basin, waste rock pile composite materials, iron-rich riverbed sediments and gossan (weathered naturally rock) were performed towards this purpose. Initial leaching experiments using distilled water kept in contact with solid material for 300, 100, 50 and 1 h resulted in very low concentrations of U with (234)U/(238)U activity ratios close to equilibrium and activity concentrations of (210)Po < 0.03 mBq/g. Leaching experiments performed with sulfuric acid media (0.1 and 0.01 M), and contact times between the solid and solution for 24 h were conducted to quantify the amount of U-isotopes and (210)Po leached, and the radioactive disequilibria generated between the radionuclides in the leachate. These experiments show that Po mobility in acidic conditions (pH around 1-2) is very low, with (210)Po activity in the leachate to be 6% in average for the solid sample. By contrast, mobility of U-isotopes is higher than that of Po, around 1.2%.
authors.affiliation: Universidad de Cádiz, Spain. Electronic address: luis.barbero@uca.es.
authors.forename: L
authors.initials: L
authors.lastname: Barbero
authors.affiliation: Universidad de Huelva, Spain. Electronic address: manuel.gazquez@dfa.uhu.es.
authors.forename: M J
authors.initials: MJ
authors.lastname: Gázquez
authors.affiliation: Universidad de Huelva, Spain. Electronic address: bolivar@uhu.es.
authors.forename: J P
authors.initials: JP
authors.lastname: Bolívar
authors.affiliation: Universidad de Cádiz, Spain. Electronic address: melquiades.casas@uca.es.
authors.forename: M
authors.initials: M
authors.lastname: Casas-Ruiz
authors.affiliation: Universidad de Huelva, Spain. Electronic address: almudena.hierro@dfa.uhu.es.
authors.forename: A
authors.initials: A
authors.lastname: Hierro
authors.affiliation: Wayne State University, Detroit, USA. Electronic address: ag4231@wayne.edu.
authors.forename: M
authors.initials: M
authors.lastname: Baskaran
authors.affiliation: Northern Arizona University, Flagstaff, USA. Electronic address: michael.ketterer@nau.edu.
authors.forename: M E
authors.initials: ME
authors.lastname: Ketterer
mesh_terms: D006863:Hydrogen-Ion Concentration; D008906:Mining; D011059:Polonium / Q000032:analysis*; D011834:Radiation Monitoring; D045483:Rivers / Q000737:chemistry*; D013030:Spain; D014501:Uranium / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis*
chemical_list: D014875:Water Pollutants, Radioactive; D014501:Uranium; D011059:Polonium
keywords: (210)Po; Acid mine drainage (AMD); Leaching experiments; U-series disequilibrium