Heavy metals in the unsaturated and saturated zone of the Upper Jurassic carbonate massif in the vicinity of Kraków

Abstract

Migration and concentration of heavy metals in infiltration waters within unsaturated and saturated zones of a carbonate massif result from their mobility as well as anthropopression. The purpose of this project, carried out in 1995-2005, was to observe changes in the chemical composition of infiltration waters, especially Sr, Ba, Fe, Mn, and Zn concentration in precipitations, in soils and in caves within an unsaturated zone and a saturated zone situated in a carbonate massif. Field research was conducted in the Prądnik River’s drainage basin and at the Zakrzówek horst in Kraków. The chemical and mineralogical composition of limestone samples from 11 different quarries and natural exposures in the Kraków Upland were studied. The mineralogical research was conducted using the Roentgen diffraction method. The concentration of Sr, Ba, Fe, Mn and Zn in 700 samples from precipitation, caves and saturated zone waters was analysed. The determinations were made using mainly the ICP-AES Plasma 40 and ICP-MS Elan method. To assess the quality aspects of the migration of heavy metals, the results of the geochemical modelling were accounted for using the PHREEQC software. The hydrochemical research has shown distinct variability of concentrations of the analysed minor elements in different forms of precipitation (the highest concentrations being observed in sleet and the lowest in pure snowfall). In rainwater as well as in waters of the unsaturated and saturated zones, quantities of the five chemical elements appeared in the following decreasing order: Fe>Zn>Mn>Sr>Ba and Sr>Ba>Fe>Zn>Mn. The chemical composition of infiltration waters in the carbonate massif changes vertically. The fundamental trends in the waters of this area include an increase of Sr and Ba concentrations, a decrease of the concentration of Zn, and static concentrations of Fe and Mn.