In this paper, results of seasonal investigations throughout 2002, important for evaluation of the eutrophication and bacterial pollution of the Montenegrin coastal sea were presented. It was established that the difference between warmer and colder periods of the year was highest in the part of the Montenegrin coastal sea exposed to the strongest impact of the open waters of the Southern Adriatic.

There have been given research results of quantitative and qualitative indices of communal and industrial waste waters of Nis. The research was carried out by the Institute "Jaroslav Cerni" (group of authors) and JKP "Naissus" (4) with the goal of defining as reliable parameters as possible in order to draw up plans for a central wastewater cleansing plant in Nis, as well as several necessary treatments of the industrial waste waters. There have been presented quantities, load and expected load of the total waste water, basic characteristics of urban and natural recipient, waste water influence on the river Nisava and needed degree of cleansing.

The aim of this work is to confirm water quality of the littoral zone of Lake Ohrid at tourist locations during the tourist season 2002. Water quality is presented through following microbiological and chemical parameters: number of psychrophilic and mesophilic heterotrophic bacteria, urolitic bacteria, most probable number of total coliforms (MPN), indicators for fecal pollution (Escherichia coli, Clostridium perfringens), chlorophyll a, dissolved oxygen, biochemical oxygen demand for five days (BOD5), organic loading and total nitrogen.

In this paper investigations of biomass of red head grass Potamogeton perfolitus L. from Lake Ohrid were presented. The material was collected from 2 localities along the Ohrid Lake's coast (Grasnica and Kaneo), where anthropogenic influence is different expressed. The results from the investigations show that there are differences in biomass between investigated localities.

In the scope of complex physical-chemical and biological water examination of Bocac water reservoir, the river Vrbas and trbutaries Ugar and Crna Rijeka, examination of standard microbiological indexes of water quality (aerobic organotrophs at 22-26 deg C and 37 deg C, total colliforms and colliforms of fecal origin) was performed during 2002 (March-November). Number of examined microbiological parameters was mainly in the scope of the 2nd water category (beta-mesosaprobic water) with worse water quality in upstream part of the reservoir. Ugar tributary had the best water quality, while Crna Rijeka had the worst status with obvious anthropogenic influence.

The paper presents theoretical model of the pollutant density changes in water environment. Spreading of the pollutant is modeled by strong pointed force on the pollution system in the water. This force appears as a strong short term pressure in certain point of the system after which it starts to move in one direction. Results of applying of this model shows that density of the pollution depends on mass of the pollution and the speed of the spreading of the pollutant in the aquatic system. One dimensional result of the pollutant density that is received, i.e. pointed direction of the pollutant stands only in the cases of precisely fixed conditions defined by modeling. For any other values that exceed these values the pollutant density value is equivalent zero value.

Bacteriological examination have been carried out within the comprehensive hydrochemical and hydrobiological investigation of river Koselska during 2002. The aim of investigations is to confirm condition of bacteriological communities and water quality of river Koselska. The results of investigations shows pollution by organic matter. In order to prevent further eutrophication processes, certain measures of river water protection and conservation should be undertaken. Also, the regular monitoring of water quality should be established.

The paper gives the contribute to analyses of the problem of Crnojevica river (Montenegro, Serbia&Montenegro) water pollution. The analyze surround measurement the next parameters: pH, conductivity, oxygen balance, sanitary parameters, content of different form of phosphorus. These measurements are carried out over five sampling series, at the seven stations, including underground flow rate in the Obod cave. Our estimations are confirmed the continuity of the Crnojevica river pollution, by municipality and strain water from Cetinje urban area. Nutrients, especially phosphates, from the pollution emission, attend conditions (together with many natural factors) for production biomass quantity. The opposite processes, the inhibition processes, exist. Phosphorus in the water attends increase level of the water pollution (over increase eutrophication degree), so the water is out of the legal class, because its usage is limited.

This paper presents longtime (1986-2001) researches waste waters quality from "Djuka Dinic" tanery, Nis (Serbia, Serbia&Montenegro), as well as their influence to recipients (municipal sewers and the Nisava river).Needed grades of purification of relevant pollutants to recipient are defined as well as schematic possible solutions for waste water purification. The most optimal solution for purification of waste water from tanery from "Djuka Dinic", Nis, is common leading of waste waters to municipal sewers (waste waters from factory 2 for pig leather treatment enter now to the Nisava river without purification) with adequate pretreatment. Based to recently experiences as well as laboratory researches pretreatment consist of: rudely dispersed material removal (grates and sieves), equalization, primary sedimentation and coagulation with flocculation and sedimentation gives good results. Meanwhile, technological purification scheme that include separation flot from leaching and tannering from common flow of collective waste waters and their special treatment, respectively repeated use, has significantly adventages: pollution decreasing of collective waste water, saving of basic reagents that use as raw materials in treatment leather in recuperation or repeated use, eliminating waste sludge with chromium and economize of purification process.

As a consequence of bombing of Novi Sad Oil Refinery, Serbia (Serbia&Montenegro), the spillage of large amounts of oil and derivatives caused hydrocarbons pollution of the area surrounding the Refinery and the river Danube, thus directly endangering the entire water source "Ratno ostro". As a measure of protection in the division zone of the Refinery and the water source area, a hydraulic barrier was constructed. Within the process of monitoring piezometer water quality and the water supplied by protection system wells, microbiological analyses of water were carried out with the aim of supervising the barrier functioning. The results have shown that bacterial populations in polluted areas exhibit a duel role: they act as bioindicators of a certain pollution, but at the same time they take part in the process of selfpurification.