Hydrochemical changes and groundwater grouping data by multivariate statistical methods within one karst system: recharge–discharge zone (Eastern Serbia case study)

To define changes in hydrochemical composition from the recharge to the discharge zone of the complex Kučaj–Beljanica karst massif, located in eastern Serbia, on a quarterly basis within one hydrologic year, a physico-chemical analysis was performed, along with the determination of ions (cations and anions) and isotope 13C content in rainwater, surface and groundwater (cold, sub-thermal and thermal). The multiparameter analysis of parameters was also used to determine the best combination and grouping of similar hydrochemical characteristics, as well as to determine the dependence of chemical parameters of the water, which may indicate the predominant complex geochemical underground processes. The results showed that the Ca2+ and dissolved oxygen O2 content in water decreases with circulation depth; while, the content of all other observed elements increases as a result of complex geochemical processes that occur within the complex karst environment