Isotopes 3H, d2H and d18O in groundwaters from Vojvodina region

This paper presents the results of the survey of groundwater samples from Vojvodina region, Serbia. By measuring the activity concentration of radioactive isotope tritium (half-life 12.32 years) the groundwater’s age could be estimated. Tritium is directly incorporated into the water molecule (H3HO), so it participates in the hydrological cycle and can be detected in groundwater. The presence of tritium in groundwater indicates recharge of aquifer by modern precipitation (i.e., recharge after 1952). Modern groundwater is renewable, as opposed to the older and fossil water, and in this sense it can be better utilized. On the other hand, modern groundwater is more vulnerable to contamination from the surface. It is important to know the approximate age of groundwater for better water resources planning and management. This study included 35 groundwater samples from deep wells and natural sources and 1 surface water sample from the lake, all collected in Vojvodina region from four different hydrogeological systems. In all collected samples stable isotopes δ2H and δ18O were measured in order to determine the origin of groundwater. For understanding and interpretation of the obtained results, geology and hydrogeology of researched area was taken into consideration. The main conclusion is that the groundwaters in Vojvodina region are mostly young (not older than 10 years) and that they are mostly supplied by precipitations. There is no direct connection between groundwater age and the corresponding hydrogeological system