Groundwater geochemical evolution under the influence of polymetallic deposit in Czarnów (Western Sudetes, SW Poland)

Abstract

Water environment in the vicinity of Czarnów (Rudawy Janowickie Mts., Western Sudetes) is characterized by an occurrence of rich variety of trace elements affecting its quality directly. Based on the analyses of chemical composition of waters supported by geochemical modeling using PHREEQC code the significant influence of either natural geological conditions or former and contemporary mining activity has been confirmed. The results of inverse modeling suggest the contribution of carbon dioxide dissolution, pyrite oxidation, carbonates and plagioclases dissolution and ionic exchange between Ca2+ and Na+ as major chemical processes influencing water chemistry evolution. The anomalous concentration of arsenic in several locations as a result of probable desorption from iron oxide–hydroxides under the elevated pH conditions can be observed. The evaluation of changes in waters chemical composition during the past three decades indicates the tendency of their self-purification.