An elevated concentration of uranium in the water of some springs in the Permo-Triassic sedimentary rocks of the Visok region, south-eastern slopes of the Stara Planina, eastern Serbia, is interpreted based on geological, hydrogeological and hydrochemical data. Uranium concentration in groundwater was first examined whilst exploring for uranium minerals as an energy resource. The purpose of a later hydrogeological investigation was assessment of a safe drinking water supply to a planned ski-centre hotel. The maximum contaminant level for uranium, recommended by the World Health Organization (WHO), is 15 μg/L. This work reviews and interprets the naturally elevated uranium in springs from the Permo-Triassic sediments of Visok, focusing on geological, hydrogeological, hydrogeochemical and other factors of uranium contamination. Uranium distribution in groundwater from Permo-Triassic aquifers was studied by taking groundwater, spring sediment and rock samples. The varied mobility of uranium depends largely on lithology, which also controls the chemistry of groundwater. The investigation results have shown that sulfate-calcium groundwater is a suitable facilitator of uranium mobility with a high migration coefficient of 0.77. Uranium concentrations in this water were up to 41 μg/L, with a Sa/Sr mass ratio of around 20, and a mineral content of about 0.5 g/L. The hydrochemistry was characteristically transitional Eh and pH neutral. Elevated uranium in groundwater has been reported globally and may be compared.

This paper presents transformations of saturated hydrocarbons of petroleum type pollutants during ex situ bioremediation of soil on the pilot heap (halde), during a period of 6 months, within the grounds of Petroleum Refinery Pančevo (Serbia). Samples for analysis were taken in time intervals of 2 weeks (P₁-P₁₂ samples). Organic substance was extracted by Soxhlet's method and quantified. Isoprenoid aliphatics, in particular pristane and phytane, and polycyclic aliphatics of sterane and triterpane types in saturated hydrocarbon fractions were analysed by GC-MS (SIM method). Significant amounts of n-alkanes have not been detected. The MS-chromatogram revealed only marginal amounts of pristane and phytane in sample P₁. Pristane and phytane occurred in sample P₈, and in even higher quantities in the final sample P₁₂. The proceeding bioremediation process was accompanied by the decrease of the relative amounts of pentacyclic terpanes of hopane type, compared to tri- and tetracyclic terpanes. In the initial sample P₁ the distribution of steranes and hopanes follows a pattern, which is characteristic for crude oils. However, their identification by SIM method was not possible in samples P₈ and P₁₂ because of the reduced concentration. The observed changes in the alkane fractions' compositions may be considered as atypical, referring to the fact that during oil biodegradation under natural conditions, decomposition of isoprenoids occurs much easier and faster than decomposition of polycyclic alkanes of tri-, tetra- and pentacyclic terpane, sterane and diasterane types, after the decomposition of n-alkanes has been almost completed.

Due to very high concentration of organic matter there is a great need for alternative solutions for drinking water disinfection in the world. Chlorine dioxide has been successfully used for almost 50 years for disinfection and later for taste removal, odor control, color reduction and oxidation of inorganic compounds such as iron and manganese. An advantage of using chlorine dioxide instead of chlorine is that it does not directly react with organic matter and form halogenated byproducts when it is used for disinfection. THMs, such as CHBr3, ChCl3 etc, are considered as most dangerous for people health. In this article we are to represent the results got from raw water disinfection treatment with chlorine dioxide.

The paper deals with the essential of economic insurance within the whole economy procedure in the water management companies. As it is well known, the fundament of insurance is risk itself. The risk, by its appearance, power and intensity, has its impacts on processes, objects and activities in the water management. That is why is very important to know and apply knowledge, awareness and comprehension about risk management in the field of water management. Any sort of risks must be analyzed, planned, controlled, organized, prevented, repressed, averted and fixed in order to decrease detriments and disadvantages. The best way to preclude all predicted and unpredicted tribulations and costs is to go all-out for the rules of covenanted and unsolicited types of insurance. The paper also gives a brand - new approach to bypassing risks within management by the system of covenanted and unsolicited insurances.

In this study possibilities for application of natural aluminosilicates, zeolites in the wastewater treatement has been investigated. Under the laboratory conditions the pilot experimental a column filled with aluminosilicates was established. Technological characteristics of the system were estimated by wastewater flow monitoring and calculation of Darcy filtration coefficient.

This study investigates the possibilities of using Lagenaria vulgaris biomass as a biosorbent for removal of heavy metals from wastewater and natural water. The experiments were carried out with model solutions of Pb2+, Cd2+, and Zn2+, in batch system. The effects of contact time, temperature, initial metal concentration and adsorbent doses, on the adsorption of heavy metals have been studied. Results show that biosorbent based on Lagenaria vulgaris represent efficient and low-cost means for pretreatment of heavy metals contaminated waters.

Explorations were done at the location Ilje, near Melenci. Novo Ilje 1 is a canal used for regulation of irrigation at the local fields. Novo Ilje 2 is a bog that dries out during the periods of low precipitation. Quantitative phytoplankton analysis of Novo Ilje 1 sample from 2003 determined that total amount of cells was 1.5 x 10**5 cell per liter. Total amount of cells in 2004 sample was 1.8 x 10**5 cell per liter. Quantitative phytoplankton analysis of Novo Ilje 2 sample from 2003 determined that total amount of cells was 1.7 x 10**5 cell per liter. Total amount of cells in 2004 sample was 3.1 x 10**5 cell per liter. Phytoplankton biomass in Novo Ilje 1 sample from 2003 was 2.6 x 10**8 cubic micrometer/l, and in 2004 sample was 1.09 x 10**8 cubic micrometer/l. Phytoplankton biomass in Novo Ilje 2 sample in 2003 was 3.06 x 10**8 cubic micrometer/l, and in 2004 sample was 1.62 x 10**8 cubic micrometer/l.

This paper shows the results of research of some phytoplankton and saprobiological characteristics of water in reservoir Grliste and the flowing rivers during the period of January 2001 to December 2007. During this period of researching, phytoplankton community was characterized by forms of Bacillariophyta, Chlorophyta, Cyanophyta, Chrysophyta, Pyrrophyta and Euglenophyta. Saprobiological analyses using bioindicatory species of algae showed oligosaprobic and beta-mezosaprobic characteristics of water in the reservoir. The analyses showed the poor water quality of Lesovacka and Lenovacka rivers which flow in reservoir. This water was determined as beta-mezosaprobic and alfa-mezosaprobic type. The phytoplankton was characterized by forms of Bacillariophyta, Chlorophyta, Pyrrophyta and Euglenophyta.