In this paper the short review of the results of calculation of the coincidence between the water level and quality parameters at the gauging station Cuprija-rail bridge (Serbia, Yugoslavia) is presented. The basic principles of the applied method and criteria for the estimation of the statistic significance of coincidence indicators are given. At the end of the analyses and comments of the obtained results, as well as the possibility for application of this methodology are given. The paper gives numerical quantities of the estimated indicators of statistical significance of the coincidence of water level and quality parameters of groundwater. Also, the graphical illustration, which shows the common exceeding probabilities of the water level and quality parameters, is presented.

Using the then years data series of organic load (COD, BOD), ammonia and organic nitrogen, total phosphorus, detergents and oxygen dissolved, a heavy pollution of Bega Canal at the Romanian - Yugoslav Border ("Srpski Itebej" Control Station) is illustrated. High load of organic matters and nutrients as well as extremely low oxygen dissolved content created anaerobic conditions in aquatic environment, are the main characteristics of Bega Canal state at the analyzed location. As the Bega Canal (left tributary of Tisza river) is an international river, a transboundary issue of pollution is considered in this paper.

In this paper the results of determination of natural waters from the territory of the township Smederevska Palanka and Rekovac (Serbia, Yugoslavia) are presented. The content of metals in waters was determined by the AAS method and other parameters were determined by spectrophotometric and potentiometric method.

In previous works numerous specific changes of water composition in the Danube backwater effects Iron Gate 1 reservoir (Yugoslavia), have been initiated. By studies of conditions of generation and composition of sediments, the models denying importance of assumption on sedimentological features of deposited materials foreseen by the project, have been established, as it was confirmed with more details by newer investigations. The new data on the character of sediments coincide in all elements with changes of water composition, which was formerly presented, thus the knowledges of these phenomena being in that way more important. The data on composition of the deposited material, the macro and micro-composition are of great importance to perceive the influence of new sediments to the quality of surface and groundwater, especially of the sources for water supply, then in a long term for the sudden high risk processes corresponding to a chemical time bomb. Data have confirmed validity of the model of intensified deposition of allochthonous material with plankton and influence of this phenomenon to the processes trough the downstream section.

In this paper, we are consider processing of soils erosion and his way on protection expoitation of water for population water supply, melioration's systems for irrigation and for strew of manger of the Lim river with the tug and suspend bank (Montenegro, Yugoslavia). We are given suggestions for protective utilization of agricultural and forest lands and the possibilities of water exploitation from Bistrica river (Montenegro, Yugoslavia). That is useful for fishing, irrigation, energetic, tourism and water supply. In this paper, you can meet some suggestions about exploitations of minerals and organic fertilizars that are not toxics and they not any influence on pollution of land and water.

During the 1994-1995, seasonal investigations of the fountainhead and spring region of the river Susica, near Uzice in West Serbia (Yugoslavia) were carried out. The bottom fauna composition, termic properties of air and water as well as chemical parameters were also determined. By the study of bottom composition 26 taxa were determined. The most uniform fauna was found in the Susica fountainhead while its diversity was increasing farther downstream the spring region.

The protected natural goods of the swamp Zasavica is situated in the north part of Macva (Serbia, Yugoslavia). It is parallel to the flow of the Sava river, which leads to the fact that it used to be the riverbed of the Sava and also of the Drina river. It is interesting for its variety of the plant and animal species. The investigations have been done during autumn period 1997, when the investigated groups were the most heterogeneous. It included algae, Rotatoria,Cladocera, Copepoda and Hydracarina. Among algae, Bacillariophyta were dominant. Among all the investigated groups Rotatoria were the most heterogenous, with great number of the species that are rarely present. Also, some Cladocera species were rare. The estimation of the water quality is given according to the bioindicator species.

In Yugoslavia, application of macrozoobenthos for the purpose of bioindication has been relatively limited. This communities has been used in conjugation with saprobiological methods, while biotic indexes have been unjustifiable used to a small extent. This paper shows the most significant biotic indexes used in the World and possibility of their application in Yugoslavia, as well as the necessity for their modification and elaboration of new ones specific to Yugoslav conditions.

The Mostonga, once the tributary of the Danube river, now a water-stream with a conducted regime it represents an important water-streams in West Backa (Serbia, Yugoslavia). The most wide-spread hydrophytes (i.e. plant species with the biggest abundance, covering values and occurrence degree) are: Wolffia arrhiza, Lemna gibba, Lemna minor, Lemna trisulca, Spirodela polyrrhiza, Ceratophyllum demersum, Elodea canadensis, Vallisneria spiralis, Stratiotes aloides, Nuphar lutea, Bolboschoenus maritimus, Typha angustifolia, Typha latifolia and Phragmites communis. Based on the analysis of bioindicating values of mentioned hydrophytes of the Mostonga it can be concluded that the present plant species are significant indicators of eutrophication (considerable organic pollution) as well as the increased contents of nitrogen and nitrogen compounds (nutrients), presence of salt in the soil and weakly aerated and mud base.

On the basis of the enzymatic (phosphatase) activity and microbiological analysis as well, the influence of the oil refinery "Vital" - Vrbas (Serbia, Yugoslavia) wastewater to the recipient DTD (Danube-Tisza-Danube) canal water from the microbiological point of view was determined. In addition the efficiency of the factory's waste water purification plant was estimated. The obtained results of the complex microbiological-enzymological analyses indicated a good water quality at the point where the refinery's water supplies plant is situated (site 1). Very low water quality was determined downstream (site 4) and upstream (site 2) from the inflow of the refinery's wastewater's inflow. The later results might indicated the influence of an unknown pollutant in the region. However, the obtained O/H index value suggests that the self-purification ability of the canal waters is still preserved.