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Bottled waters were analyzed for different chemical parameters and activity concentrations of radionuclides. The hydrocarbonate ion was dominant in all samples, while the major cation composition was a combination of Ca-Mg-Na ions. Physicochemical properties of bottled water samples are influenced by underlying geology. The sum of trace element concentrations varied from 79.7 to 9349.7 μg/l. The Dietary Reference Intake (DRI) system was applied and contributions of some essential elements were calculated according to age group and gender. Hierarchical Cluster Analysis (HCA) grouped bottled water samples into four clusters based on the similarities of the groundwater quality and essential elements concentrations. The origin of radioactivity is natural and could be traced to minerals in felsic igneous rocks. Two brands exhibited elevated beta activity (1.087±0.134 Bq/l; 1.242±0.146 Bq/l). Effective doses were found to be below the reference level of 0.1 mSv/yr. [Projekat Ministarstva nauke Republike Srbije, br. III 43004]

Multivariate statistical analyses are used for reducing large datasets to a smaller number of variables, which explain main hydrogeochemical processes that control water geochemistry. Factor analysis (FA) allows discovering intercorrelations inside the data matrix and grouping of similar variables, i.e. chemical parameters. In this way new variables are extracted, which are called factors, and each factor is explained by some hydrogeochemical process. Applying FA to a dataset that consists of 15 chemical parameters measured on 40 groundwater samples from Serbia, four factors were extracted, which explain 73.9% of total variance in the analyzed dataset. Interpretation of obtained factors indicated several hydrogeochemical processes: the impact of sea water intrusions and volatiles in previous geological periods, solutes diffusion from the marine clay, cation exchange and dissolution of carbonate and silicate minerals. [Projekat Ministarstva nauke Republike Srbije, br. 43004]

Activity concentrations of radionuclides 40K, 228Ra, 226Ra, 238U and Th232 and gross alpha and beta activities were analyzed in more than 100 samples of groundwater in Serbia. The highest gross alpha activity was recorded at 1.33 Bq/L (average 0.12 Bq/L), while the highest beta activity was 5.43 Bq/L (average 0.68 Bq/L). The potassium isotope 40K exhibited the highest active concentration (2.6 Bq/L) and was the largest contributor to the gross natural beta activity. Among the analyzed samples, 28 were found to have elevated beta activity concentrations, of which five samples also measured elevated alpha activity. All the groundwater samples that exhibited elevated radioactivity were of the HCO3-Na type and were genetically associated with granitic rocks. Their TDS levels and CO2 gas concentrations were also elevated. [Projekat Ministarstva nauke Republike Srbije, br. 43004]

Twenty-one bottled mineral and spring waters from Serbia were analyzed for 16 inorganic chemical parameters, including lanthanides and yttrium which belong to the group of so-called rare earth elements (REE). REE concentrations in the bottled water samples varied over a broad range, from 5.39 to 1585.82 ng/L. Total concentrations in the bottled water samples were calculated taking into account the classification of lanthanides into heavy (HREE) and light (LREE), with yttrium added to the HREE group. The LREE concentrations ranged from 3.62 to 1449.63 ng/L, while those of the HREE were from 0 to 136.19 ng/L. Distinct REE signatures were observed in waters that drained specific rocks. The REE patterns in groundwater from granitic and related rocks showed LREE and HREE enrichment, while groundwater with mafic rock influence exhibited slightly LREE enrichment. Several bottled water samples featured naturally-occurring carbon dioxide, whose solutional capacity contributed to the highest REE concentrations in the analyzed samples. High REE concentrations are also a result of sudden changes in oxidation-reduction conditions, which particularly affect La, Ce and Eu. Aquifers developed in granitic and related rocks (methamorphic and sedimentary rocks) constitute favorable environments for HREE in groundwater, corroborated by the occurrence of HREE in bottled water samples. The bottled water samples largely exhibited a negative cerium anomaly and nearly all the samples showed a positive europium anomaly.

An estimate of deep groundwater temperature is necessary for the research and utilization of this geothermal resource. Geothermometers are based on the temperature relation of some chemical reactions or the solubility of some minerals. Researchers mostly use silicon-based (quartz, chalcedony, amorphous silica) and cation-based (Na-K, Na-K-Ca, Na-K-Mg, and so forth) geothermometers. Temperatures of some prospectively abundant geothermal water resources in Serbia are estimated using the silicon-based geothermometers. In the absence of hot water resources, temperature of deep thermal groundwater has to be estimated and considered for power generation with the Kalina or the Rankine binary cycle. Best thermal waters (temperatures from 130 °C to 160 °C) for the purpose are located in the spa of Vranjska Banja, followed by Kuršumlijska, Sijarinska, and Jošanička spas and Bogatić of Mačva. Pumped at the present rate of 200 l/s, the mentioned sources may generate 70 MWt, of which some 30 MWt the Vranjska Banja alone. Total power (for the five tested resources) is estimated at about 2200 TJ per year. [ABSTRACT FROM AUTHOR]