Ľubietová and Špania Dolina mining areas belong to the most important Central European historic Cu-deposits. The ore mineralization contain not only Cu but also toxic As and Sb which contaminate the country components. The Eh/pH diagrams enable informative indication of As speciation in sediments and soils in the surrounding of the abandoned deposits. The most important As form in technogenous sediments of both studied ore fields Ľubietová and Špania Dolina is the less toxic As⁵⁺ speciation. The Eh/pH stability diagrams indicates predominantly occurrence of Fe(OH)₄As, H₂AsO^4-, HAsO₄^2- forms. Only in several few samples of technogenous sediments and soils As falls to the As³⁺ stability fields, e.g. to the Fe²⁺ + As³⁺(aq) field. Arsenic content in water depend on arsenopyrite FeAsS and tetrahedrite (Cu,Fe,Ag,Zn)₁₂(AsSb)₄S₁₃ decomposition. Its redeposition is realized by adsorption on Fe-oxyhydroxides surface. Arsenic content is controlled also by next degradation of secondary As phases under changed thermodynamical conditions. Both main As speciations (As³⁺ and As⁵⁺) occurs in groundwater approximately in a balanced portions. Arsenic in samples falls mainly to the H₂As⁵⁺O^3-, HAs⁵⁺O₄^2- and H₃As³⁺O₃⁰ stability fields. Arsenic speciation in surface water from both localities is in comparison with those of groundwater more close to the less toxic form As⁵⁺ (H₂AsO^3-, HAsO₄^2-, H₃AsO₃⁰). Technogenous sediments and waters at Ľubietová and Špania Dolina are also contaminated by Sb. In sediments and soil from Ľubietová Sb prevail in less toxic degree Sb⁵⁺ and is present in SbO^3- form, while in dump-field and in tailings at Špania Dolina one part of samples characterized by Eh<0,1 values is concentrated in Sb³⁺ stability fields of valentinite Sb₂O₃ and stibnite Sb₂S₃. Arsenic and antimony in surface waters and groundwater at both localities indicate application of Eh/pH stability diagrams presence of Sb predominantly in Sb₄O₆ and Sb₂O₃ forms, it means in form of more toxic Sb³⁺. The samples from Špania Dolina are in comparison with those from Ľubietová mowed down to more negative Eh values.