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.

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.

Eutrophicationn problems in the Kotor bay were studied monthly from September 2003 to August 2004. As a result of nutrient enrichment (directly dependent on human activities), phytoplankton growth was very intensive, reflected by high concentration of chlorophyll a (7.46 mg/cubic m).

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 paper presents the seasonal overview of horizontal distribution and abundance for the species of genus Oithona in Bokokotorski Bay. Three species have been recorded. Oithona helgolandica and Oithona plumifera have a wide horizontal distribution within the Adriatic Sea, while Oithona nana is a typical euritherm and eurihaline form that occupies shallow and closed coastal areas along the eastern coast of Adriatic. Also presented are seasonal oscillations and quantitative presence of these species in the Copepoda population during 2002.

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.

Potentiometric stripping analysis (PSA) is highly sensitive electroanalytical method for determination of traces of heavy metals. In this paper detection limit and linearity of potentiometric stripping analysis for lead was investigated. Method was successfully used for determination of traces of lead ion (detection limit 5 microgram/cubic dm) in stream water of river Ibar, before and after joint of potential pollutant.

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 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.