Geochemical and mineralogical characteristics of the soil in the area of Velika Gorica watter wells : master’s thesis

Predmet istraživanja ovog rada su uzorci tla s područja vodocrpilišta Velika Gorica. Cilj rada je određivanje geokemijskih i mineraloških značajki tla na području vodocrpilišta Velika Gorica. Laboratorijska analiza uzoraka tla je obavljena na Zavodu za mineralogiju, petrologiju i mineralne sirovine Rudarsko-geološko-naftnog fakulteta Sveučilišta u Zagrebu u proljeće i ljeto 2016. godine. Utvrđeno je kako su koncentracije potencijalno toksičnih elemenata (Cu, Cd, Zn i Pb) te kationa i aniona (Na+, K+, NH4+, Mg2+, Ca2+, Cl-, NO3-, NO2- i SO42-) značajnije u sloju dubine do približno 80 cm. Ispod navedene dubine dolazi do pada njihove koncentracije kao posljedica granulometrijskog sastava u kojem dominiraju prah i glina koji uvjetuju slabiju propusnost tla. Koncentracije navedenih kemijskih tvari u podzemnoj vodi posljedica su utjecaja različitih izvora onečišćenja s velikog priljevnog područja zagrebačkog vodonosnika. S obzirom na smanjenje njihove koncentracije s dubinom i na dubinu do podzemne vode (više od 750 cm) u blizini lokacije uzorkovanja, utjecaj koncentracije analiziranih kemijskih tvari iona u površinskom sloju tla na podzemnu vodu je zanemariv te kvaliteta podzemne vode nije ugrožena.Abstract: The subject of this study were soil samples of the area of Velika Gorica water wells. The aim of this study was to determine the geochemical and mineralogical characteristics of the soil in the area of Velika Gorica water wells. The laboratory analysis of soil samples was conducted at the Department of Mineralogy, Petrology and Mineral Resources at the Faculty of Mining, Geology and Petroleum Engineering of the University of Zagreb in the spring and summer of 2016. The analysis showed that the concentrations of potentially toxic elements (Cu, Cd, Zn and Pb) as well as cations and anions (Na+, K+, NH4+, Mg2+, Ca2+, Cl-, NO3-, NO2- and SO42-) are significant in a layer of up to about 80 cm. Their concentration decreases beneath the specified depth as a result of particle size distribution, dominated by silt and clay that determine a lower permeability of the soil. Concentrations of these chemicals in groundwater are the result of the influence of different sources of pollution from the large inflow area of the Zagreb aquifer. Due to a decrease in their concentration with depth and distance to the groundwater (more than 750 cm) near the sampling location, the impact of the concentration of the analyzed chemicals in the surface layer of soil to the ground water is negligible and groundwater quality is not compromised