Mobility and attenuation of arsenic in sulfide-rich mining wastes from the Czech Republic

0460472 - GLÚ 2017 RIV NL eng J - Článek v odborném periodiku
Drahota, P. - Knappová, M. - Kindlová, H. - Culka, A. - Majzlan, J. - Mihaljevič, M. - Rohovec, Jan - Veselovský, F. - Fridrichová, Michaela - Jehlička, J.
Mobility and attenuation of arsenic in sulfide-rich mining wastes from the Czech Republic.
Science of the Total Environment. 557/558, July 01 (2016), s. 192-203. ISSN 0048-9697. E-ISSN 1879-1026
Institucionální podpora: RVO:67985831
Klíčová slova: arsenic * mining waste * mobility * pore water * secondary arsenic minerals
Kód oboru RIV: DD - Geochemie
Impakt faktor: 4.900, rok: 2016

The mineralogical composition of mining wastes deposited in countless dumps around the world is the key factor that controls retention and release of pollutants. Here we report a multi-method data set combining mineralogical (X-ray diffraction, electron microprobe and Raman microspectrometry) and geochemical (sequential extraction and pore water analysis) methods to resolve As mobility in two 50-years-old mining waste dumps. Originally, all of the As in the mining wastes selected for the study was present as arsenopyrite and with time it has been replaced by secondary As phases. At Jedová jáma mining area, the most of As precipitated as X-ray amorphous ferric arsenate (HFA). Arsenic is also accumulated in the scorodite and Fe (hydr)oxide (with up to 3.2 wt.% As₂O₅) that is particularly represented by hematite. Mining wastes at Dlouhá Ves contain only trace amount of scorodite. Arsenic is primarily bound to Pb-jarosite and Fe (hydr)oxides (especially goethite) with up to 1.6 and 1.8 wt.% As₂O₅, respectively. The pore water collected after rainfall events indicated high concentrations of As (~4600 μg•L^-1) at Jedová jáma, whereas aqueous As at Dlouhá Ves was negligible (up to 1.5 μg•L^-1). Highly mobile As at Jedová jáma is attributed to the dissolution of HFA and simultaneous precipitation of Fe (hydr)oxides under mildly acidic conditions (pH ~ 4.4); immobile As at Dlouhá Ves is due to the efficient adsorption on the Fe (hydr)oxides and hydroxosulfates under acidic pH of ~2.8. Taken together, As mobility in the ferric arsenates-containing mining wastes may significantly vary. These wastes must be kept under acidic conditions or with high aqueous Fe(III) concentrations to prevent the release of As from incongruent dissolution of ferric arsenates.
Trvalý link: http://hdl.handle.net/11104/0260542