During the analyses of zooplankton and hydrography samples from continuous field research in monthly series during 2002 on three shallow stations (Orahovac, Morinj and near the Institute) and 4 central stations in Boka Kotorska Bay (Adriatic sea, Montenegro (Serbia&Montenegro)), exceptionally dense populations of Penilia avirostris were observed. Presence of this species in refreshed waters during the summer in other parts of Adriatic and Mediterranean, and its designation as an indicator, are reasons for presentation of these gathered results from yearly cycle in Boka Kotorska Bay.

Having known the fact that on the territory of West-Backa region the only water used for water supply system is subterranean water, from different water layers, an assumption can be made that the waters also differ in their physical and chemical content. It is also assumed that these waters differ in their total iron content. The aim of this work is to test the significance of the difference between central water supply systems of West-Backa region (Sombor, Apatin, Kula and Odzaci) for the value of iron in drinking water, using the adequate statistics methods. The central water supply systems in Sombor, Apatin, and Kula are using water from the second water layer (60-75 m), while the water supply system in Odzaci is using deep artesian and subartesian waters (146-220 m). Sombor and Apatin have the raw water purification system and one of the goals is to decrease the concentration of total amount of iron in drinking water.

The results of a study on the water of the Sumanka river during several years point out the decrease in its quality. The results of the present study show that the technological actions, as well as the some technical changes, carried out in the Lebane's plant in Grgurovci gave the satisfactory effects. Turbidity, colour, KMnO4 demand and ammonia are efficiently reduced, along with low concentrations of Fe, Mn, and residual Al, ensure completely the water standard quality in accordance with the Protocol.

Water reservoir "Gruza" is used forthe water supply of the town of Kragujevac and it's surroundings. The paper shows a comparative overview of physical, chemical and microbiological parameters during the period of 1987-1989, and 1997-1998. Variations of physical, chemical and microbiological parameters are given in the paper.

Author described the beginnning of organized supply Zajecar, Serbia (Serbia&Montenegro) with drinking water and the establishment of Public Firm for Water Supply. In this paper author shows the results of five-years analysis of drinking water and the influence of water quality on human health during this period of organized supply with water.

Available data on zooplakton research in Adriatic sea show that coastal and open waters of south Adriatic are the zone of most available and richest area in Adriatic sea. Shallow waters along the shore and the Boka Kotorska Bay are characterized by a monotony of faunistic content, while, by contrast, high values of biomass are caused by abundance of a small number of estuary-neritic species. Open waters of South Adriatic are characterized by holoplankton, while waters of Boka Kotorska Bay are characterized by meroplankton. Zooplankton of open sea shows a high diversity of fauna but a small biomass in part of open water above the geatest depths, and significantly high values of biomass in epipelagic waters above the continental shelf.

Comparative analysis of results obtained in hydrobiological research conducted to date indicates that relatively few water reservoirs in Serbia have been subjected to complex hydrobiological investigations. Apart from the fact that hydrobiological investigations are now performed on only a small number of water reservoirs in Serbia, they are moreover inadequately coordinated, which is especially evident in differences of procedural approaches employed. With adoption of the principles of modern limnology and wider use of new criteria for water classification (m WQI for instance), the current state of hydrobiological research constitutes a basic for the development of comprehensive program of planned continuous studies of water reservoirs in Serbia resulting in their rational and successful management.

This work show and compare results of chlorophyll 'a' and phaeophytin 'a' concentrations during three years systematic examination. The samples were collected from the fourth sector of Palic lake, ones a month, during 2000, 2001, and 2002 using method by Szilagyi. Comparing values, a great seasonic changes of chlorophyll 'a' and phaeophytin 'a' concentrations is noticed.

The lack of drinking water in Zajecar was the main reason for building of water barrier on the Grliste river and making the water reservoir. A factory for water processing was also built, but the problems were not disappeared. The conclusion is that the main solution for this ecosystem was in establishing of an monitoring system. That is the reason why we talk out the results of the monitoring and the troubles in this water source as well as in the phases of water processing.

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.