The work considers the effect of the ozonization process on the change of contents of natural organic matter (NOM) and formation of byproducts in the groundwater pretreated by preozonation (2.0 g O3/cubic m) and coagulation with polyaluminium-chlorosulfate (5 and 10 g Al/cubuc m). Experiments were carried out on a semi-industrial plant of capacity of 2 cubic m/h, using groundwater with a high content of NOM (5.1 mg/l TOC). It was found that in the course of ozonization NOM content shows a decrease (18-64%), as well as the potential of formation of trihalomethanes, PFTHM (12-59%), whereas content of aldehydes increases by 3.0-7.7 microgram/l, depending on the water pretreatment and applied ozone dose. It was found correlation between specific aldehyde content and decrease of the specific PFTHM (r=0.815-0.998).

The results of the evaluation of the radiological safety of the drinking waters originating from the territory of Serbia were studied during 2004. The total of 121 samples were examined for the total alpha and beta specific activity. Radiologically correct were 92% of drinking water samples.

The paper presents main recommendations for monitoring groundwater from the aspect of the EU Water Framework Directive. It is concerned with some basic notions of monitoring of quantitative and chemical state of groundwater. It is pointed out that the network of gauging stations must be planned for every catchment area, to ensure a holistic and all-encompassing survey of the chemical state of groundwater, and allow detection of long-term anthropogenic effects of pollution. In addition to usual numerical and graphical presentation, the state of groundwater quality should be also presented by colours: good state - green, bad state - red.

Man-made lakes cause direct and indirect changes in environmental conditions downstream of the water reservoir. Management must consider these water quality and environmental effects as well as uses of the river below the water reservoir.

The results of the examination point out on heterogenity of the phytoplankton community. The presence of 212 taxa has been noted. In the way of quality the green algae are dominant. In all the aspects of the quantitative analysis the domination of Bacillariophyta has been noted, first of all the centric forms. The amount of nutrients on the locality of border with Hungary is considerable, thus during low water and high temperature, the intensive algae development is usual.

Wastewater from the Novi Sad Oil Refinery, Serbia (Serbia and Montenegro) had been previously discharged to the Danube river between the raw water wells. In order to protect water supply source, the collector discharge was displaced downstream, outside the raw water wells area. In 2004, the quality of Danube river water and sediment was monitored at the sites of the old and new collector discharge of the Oil Refinery wastewaters, as well as at two control (reference) sites. The paper presents chemical quality parameters of water and sediment, characterizing oil contamination. Significantly increased contents of oil contaminant were measured in the Danube river sediment at the old discharge site compared to other sampling points, which is a consequence of many-year accumulation, as well as in the Danube river water at the new discharge site, as a consequence of the present wastewater discharge.

During 2004 the referent monitoring of chemical quality of surface water and sediments in some protected areas in Vojvodina was conducted as a supplement to the regular monitoring program in Vojvodina. The aim of the study was to establish the chemical quality of surface water and sediments. It is concluded that the water quality satisfies the criteria of class 1/2 according to national legislation. With regard to contamination of sediments with organic micropollutants the sediment of Lake Ludos may be considered as potentially problematic because the Canadian empiric effect guideline value as well as sediment quality reference values according to Dutch legislation were exceeded for DDT and its derivatives.

Eutrophication is one of the main problems of water deterioration in accumulation lakes. Phosphorus is considered as the key factor for eutrophication of lacustrine water. Its concentration in lakes originates from external input and the emission from the sediment. It was necessary to determine the substrates of phosphorus by sequential extraction in order to determine the dynamics and bioavailability of phosphorus. On the basis of results obtained the proposals for the preparation of land were made in order to minimise the input of phosphorus.

Some physiological groups of bacteria can be good indicators of the oil pollution of the environment. Oil contamination represents a special problem because of their persistence and possibility of reaching drinking water supply sources. The destruction of the Novi Sad Oil Refinery in the hinterland of water supply source Ratno Ostrvo has endangered drinking water supply of the city of Novi Sad. As an acceptable protection measure appeared the solution with the hydraulic barrier located along the east side of the Refinery, bordering with the water supply source. Physiological groups of bacteria relevant to oil contamination (hydrocarbon-oxidizing and lipolytic bacteria) were detected in the waters of the barrier wells. The appearance and population of this microflora in the water of these wells were more pronounced compared with the waters of a control piezometer in the hinterland of the water supply source.

In the last few years, in Montenegro there were positive movements into fulfilling the principles of sustainable marine fishery, primarily throught introducing the Law on Marine Fishing and its rules. Institure of Marine Biology in Kotor, Montenegro, in cooperations with the Ministry for Agriculture, Forestry and Water Management of the Republic of Montenegro, works on undertaking of the measures that may ensure optimal regulation of fishing. These measures were based on scientific research, particularly on the estimates of parameters of population dynamics, biomass and maximum biologically sustainable utilization of economically important species on Montenegrin coast.