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.

The river Gvozdac (Serbia, Yugoslavia) is a small hill water current. It is situated on the mountain Goc and it belongs to the river basin of the river Ibar. During 1965, water micro-reservoir "Gvozdac" on the river Gvozdac was built for the hydroenergetic purposes, with the capacity of about 30,000 cubic meter and the maximum depth, in the present situation of about 2.5 m. Algological and saprobiological enquires have been performed on the water micro-reservoir, on the very river Gvozdac, on the river Ribnica and on some smaller stagnant waters on the given area, in the period between 1988-1994. The analysis have been shown that under the influence of antropogenic factors changes became apparent in the confluence and structure of algae flora as well as a degradation of water quality. The example of water micro-reservoir on the river Gvozdac indicates the destructive processes which are being developed in water micro-reservoirs and which should be stopped, as the significance of the small stagnant waters are not only in keeping and improvement of qualities of greater aquatorials and water tributaries of the river basins but also in the storing of biodiversity of aquatic assotiations in river basins (as well as in algae flora as one of the components).

The investigations of dynamics and composition of plankton, bottom fauna and fish community have been done at three localities (1-inflow, 2-the middle, 3-dam) at the Barje water reservoir (Serbia, Yugoslavia) during 1997. During winter period diatomea Asterionella formosa was dominant at all the localities. At the same time among zooplankton species Rotatoria group was dominant, with the emphasis of Polyalthra dolicoptera at the locality 2, while Keratella cochlearis was dominant at the localities 1 and 3. The present species are oligo- and betamezosaprobionts. Among the investigated bottom fauna species Oligochaeta and Chironomidae were present. The number of oligochaeta was between 1665-7878 ind./square m. By qualitative analyses the domination of Tubificidae family was present. It is known that the presence of this group of organisms and it's high number indicate the organic pollution of ecosystem. 30 individuals of the bighead, (Hypophthalmichthys nobilis) with the average weight of 5.6 kg was captured by net.

Competing ions strongly affect heavy metal sorption onto the solid surfaces of soil. This study evaluated competitive sorption of Cd, Cu, Ni, Pb and Zn on three soils: Calcixerollic Xerochrept, Paralithic Xerorthent and Lithic Haplumbrept. Monometal and competitive sorption isotherms were obtained at 25°C. The individual effect of ions on retention of the others was ascertained by a fractional factorial analysis design. Most of the sorption isotherms belonged to type L subtype 2 in the classification of Giles. In competitive sorption the initial linear part was shorter and the knee sharper when compared with monometal sorption isotherms. Parameters related to sorptive capacity, such as Point B, Langmuir monolayer and Freundlich distribution coefficient, were higher in monometal than in competitive sorption, and in basic soils than in acidic soil. Calcium desorbed at different points of the sorption isotherms indicated that cationic exchange with Ca was the main retention mechanism in calcareous soils. For Pb, the ratio Ca desorbed/Pb sorbed was close to one; for Cu, Ni and Zn the ratio ranged from 1.20 to 1.37, probably due to partial dissolution of calcium carbonates by hydrolytic processes during retention. On the other hand, Cd had a ratio around 0.6 reflecting another additional retention mechanism, probably surface complexation. Fractional factorial design confirmed that the presence of the cations investigated reduced the amount of the five metals retained, but the presence of Cu and Pb in the system depressed Ni, Cd and Zn sorption more than the inverse. Cation mobility was enhanced when equilibrium concentration increased and the effect was higher in Ca-saturated soils.

Amplified and accelerated eutrophication process is a characteritic of a whole variety of small and medium-sized water-bodies, such as channel systems, microreservoirs, ponds, lakes and bank regions of many even bigger ecosystems. During the process, in relatively short period of time, the upper capacity limit of a certain biotop is far too exceeded, which leads to reduced ability of ecosystem's autopurification. As a consequence of such degradation, ecosystem faces a serious discrepancy between members of a biocenosis e.g. in ration producers/consumers/decomposers, which, in the end, causes destruction, e.g. dystrophy of the hydroecosystem. The introduction of diverse fish communities, can, therefore, be one of the basic measures for enabling a sustainable trophic stability, in a sense of keeping a dynamic balance. This measure includes carefully planed fish community - it should consist of three basic components of a trophic food web (planktivore and macrophytovore, bentivore and carnivore). Apart from enabling certain biodiversity considering particular fish species (both quantitative and qualitative), care must be inevitably taken of age structure, as well as fish stock and fishing dynamic, concerning the number, quantity and age.