ABSTRACT: There is arsenic contamination at Pezinok mining site in the Southwest of Slovak Republic. Investigation of this site based on sampling of pore water in mine tailings, ground water in surrounding aquifer and surface water, mineralogical analyses, and flow and geochemical modeling revealed the extent of contamination and identified natural attenuation processes. The evaluation of modeling study could help to propose the elimination of such contamination. On the basis of many field measurements of groudwater depth and discharge in Blatina river the conceptual and hydraulical model was established. With the help of model the placement of geochemical barrier and drain system was proposed, which could effectively grab contamination transported by ground water. On the data analyze basis the treatment of Buducnosť adit was recommended together with covering of tailing pond area by impermeable material such as clay sediments, which could eliminate discharge of water into it.