There are presented the results of investigations carried out in the Kotor Bay (Adriatic Sea), Montenegro (Serbia and Montenegro) during the winter months of 2004. The highest value of microphytoplankton as a greater size-fraction of phytoplankton is found in the surface layer during March (1.4 x 10**7 cells/cubic dm). The main edificator was diatomic species Skeletonema costatum with relative percentage about 100%. Obtained results point out that Kotor Bay belongs to the highest eutrophic or extreme eutrophic area. Similar result is found in the same period twenty years ago.

In this paper, we used similarity index, such as Sorensen similarity index (S), Jaccard similarity index (Cj) and Percentage Similarity Index (PSC), to show similarities and contrasts within the qualitative structure of zooplankton of various bays within Boka Kotorska. This kind of statistical overview was made for Boka Kotorska Bay for the first time, so we believe that it is a valuable contribution to recent studies on zooplankton. Tables show the results for each index individually, as well as the smallest and greatest similarity among the bays. We also presented the number of recorded species in the Boka Kotorska Bay arranged by months for three different years.

The 1st South-Eastern European Interlaboratory Study: WATER ANALYSIS - 2003 was organized by International Scientific Committee on the basis of international European and regional experiences. The total of 38 laboratories took part in WATER-ANALYSIS 2003. Three laboratories were from Greece, two from the Republic of Srpska (Bosnia and Herzegovina), eight from Romania and all others from Serbia and Montenegro. Two samples were prepared from water of the river Danube and the task for participants was to determine trace elements: Al, As, Cd, Cu, Mn, Fe, Pb, and Zn. Results of determination of arsenic (As) and aluminium (Al) are presented in this paper.

Organic matter of various composition is present in soils and sediments ranging from simple compounds to the very complex proteins, etc. Within the pollutant analysis in soils and sediments the total organic carbon (TOC) content is determined. In addition to this form carbon may be present as elemental or inorganic ones. TOS identification and quantitation methods may be qualitative or quantitative with prior sample preparation. It is recommended catalytic combustion of samples at high temperatures with Pt catalyst and IR detection of evolved CO2.

Problematics of humic substances removal from surface water with low mineralization and temperature near zero was presented. In this analysis very large spectar of solutions especially for this area was included. More detailed data obtained with this patent solution (7) in laboratory conditions on purificaton of raw water are presented in the analysis. Comparing the new technology with existing purification state and many unsuccessful attempts to obtain the standards gives the possibility of choosing the best drinking water treatment solution for plant on mountain Kopaonik. General estimation of different methods that can give necessary water purification level was done. Technoeconomic and ecological analysis of different water purification methods was realised and the a rational solution with high effects on protection of the environment was given.

The paper outlines the significance of studying and analysing sediment deposition issues in drainage canals in Vojvodina, Serbia (Serbia and Montenegro). This problem needs to be properly addressed considering the total length of the canal network, that is, the total volume of sediment to be removed by dredging if the functional performance of the canal network is to be restored and maintained. Much of the effort needs to be focused to the polluted sediments with a severe risk for the environment. Sediment pollution is caused by the point and non-point sources of pollution. Taking one drainage canal as the example, essential chemical properties of the sediment and hazardous and toxic substances contents (heavy metals, PAHSs and PCBs) are being analysed and presented in the paper.

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.

A new concept for the determination of reference low flows of natural watercourses - the guaranteed minimum - has recently been introduced into the water management practice. Appreciating the significance underlying the definition of low flows in all segments of water management (municipal and industrial water supply, wastewater discharge, irrigation, navigation, hydropower, water protection, etc.), the author believes that all aspects of the problem must duly be considered, examined and identified. The doubts and issues raised by the guaranteed minimum concept in the domain of random-probabilistic phenomena, such as river discharge, are discussed in the paper.

The paper contains description of potential approaches to better defining of distribution curves parameters for low water levels on water courses that sporadically dry up, also including additional information on the length of dry period. Computed results are given for the example of minimum annual discharge on several rivers in the Velika Morava basin, Serbia (Serbia and Montenegro).

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.