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Abstract:

This article reports the results of a study concerning contamination of the dump-fields by potentially toxic elements at five abandoned copper mines: Ľubietová, Špania Dolina (Slovakia), Libiola, Caporciano (Italy) and São Domingos (Portugal). This paper offers an updated description of soil contamination at the individual deposits and indicates a possible solution of the derived environmental problems. Contamination of technosoils by PTEs at the dump-fields shows an irregular spatial distribution of Fe, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Sb and Pb. Contents of PTEs often exceed both national and EU law limits. Whereas at Ľubietová, Špania Dolina and Caporciano the environmental risk is limited, at Libiola and São Domingos it seems to be very heavy. The technosoil (slag) of the dump-fields is not well aerated and the soil colloids have (except for Špania Dolina) negative surface charge, so they are suitable for PTEs sorption. The main environmental risk in the mining area of Sao Domingos district is the long time formation of acid mine drainage water and the high Zn, As and Pb contents. The release of PTEs to the environmental components may be limited by phytostabilization and immobilization of metals, by suitable admixtures into the technosoil/slag. The environmental situation at Caporciano is not so compromised as at São Domingos mining area. Phytostabilization will be able to stop erosion, and installation of wetlands under the dump will stop the release of Cu to the environment.