Hydrogeochemical investigation and environmental status of ground water and water accumulations in the neogene-quaternary sediments of Bela Crkva

Abstract

Regional hydrogeochemical prospecting included the Bela Crkva area, between the Nera and the Karaš rivers, draining the Neogene and Quaternary sediments. In this region and beyond, in line with the results of regional research, semi-detailed geochemical investigations were performed for identification of mineral deposits, as well as sources of water supply in rural settlements. During the prospecting, samples were collected from surface water streams, springs, wells, drills, water reservoirs, as well as the samples of stream sediments and rocks. For water supply of smaller settlements, hydrogeochemical tests are especially important. In the waters of Vrsac hills, elevated levels of radionuclides U, Ra and Rn, and other toxic elements were detected, that were above the maximum permited levels for drinking water. The wells of rural households had increased levels of Fe and Mn, as well as increased mineralization, conductivity, and nitrogen cycle. The concentration of heavy metals in water wells was increased in the most communities around the Bela Crkva, as well as in Češko Selo, Banatska Subotica, Kuštilj, Jablanka and Karaš river. From the water accumulations formed in the Quaternary sediments southwest from the Bela Crkva, samples of water, mud, overbank sediments, and A-horizon were collected. In the water samples the following was determined: Na, K, Ca, Mg, Fe, Mn, Al, NH4, NO3, SO4, HCO3, Cl, F, Ep, Eh, pH value, mineralization, Pb, Cd, Co, Ni, Cr, Cu, Zn, H2S, O2, CO2, U, Ra, Rn, As, Hg, Br. In the solid samples, Au, Ag, Pb, Zn, and other elements, as well as content of 238U, 232Th and 40K were determined. Test results are presented in the tables and diagrams, and on hydrogeochemical maps.