The lake Provala near Vajska (Serbia, Yugoslavia) was created by the embankment performation during high Danube river levels in 1924. It is a very important water ecosystem of natural origin, which is a fact of great importance for exact biological and ecological research. Miljanovic (1996) and Pujin (1997) present the first lake Provala water state data. They emphasise the reinforced eutrophication process in the shore region. This paper presents the review of the macrophytes vegetation of the lake Provala recent state for the first time, with special attention to dominant plant species. Based on the present taxons analysis, as well as water chemical parameters analysed (NH4(+), NO3(-), NO2(-), PO4(3-), HPK, BPK, pH), it can be concluded that the eutrophication process is present in this water micro-reservoir. It is especially true for the shore region and shallow waters, where the process is already well under way and very fast. These research results can be used to efficiently protect this natural water ecosystem.

Aim of this study was to assess quality of the Danube sediment from the water source "Ratno Ostrvo", which is in the vinicity of the Oil Refinery "Novi Sad" (Serbia, Yugoslavia), after bombardment of the refinery in 1999. In the period March-October 2000, sediment samples were analysed for their oil and oil-derivates contents, i.e. mineral oils contents, by quantitative IR-spectrophotometry, and by qualitative and quantitative GC/MS analyses for their polycyclic aromatic hydrocarbons (PAH) contents. Oil pollution was detected in sediment samples.

One of the very dangerous pollution of environment are heavy metals. They are "indestructible" at the condition which leads at the environment. Pollution of heavy metals is irreversible process, except if they are physical removed from the environment which they are polluting. We determinated heavy metals (Pb, Cd, Cu, Zn, Cr, Ni and Co) in the mud of three fish ponds by means of sequential extraction, because of possible mobility in the mud and its concentration increase in the water. This method was selected because we wanted to determine distribution of heavy metals by substrates, and analyse was worked by the method of AAS. The results are showing that the concentration of all metals is in the extent of "natural phone" of lakes sediment.

Microbiological examination have been carried within the comprehensive hydrobiological investigation of Grosnica reservoir (Serbia, Yugoslavia) during 1997 and 1998. The aim of investigation was to establish the dynamics and fluctuation of specific physiological group. Grosnica reservoir with its microbial features belongs to quality class 1st-2nd according to Kohl. The comparison of bacteria community varies during the year depending of physicochemical features of a environment and the state of other facts in biocenosis. Dominant bacteria are facultative oligotrophic. The larger number of heterotrophic bacteria is in spring time only. Phosphomineralizers and proteolytic bacteria are present in the large number at the beginning of year, amylolytic bacteria are numerable during the summer and autumn. Number of nitrogen fixing bacteria and aerobic cellulolytic bacteria are changed depending on a season, too.

This paper is an abstract of the operative program for water protection in the Republic of Serbia (Yugoslavia) for the next five-year period of time (2001-2005). There is a short review on the present water protection status, particularly status of wastewater treatment plants. It includes layouts of water protection solutions in different fields, by priorities, as well as assessment of necessary capital investments for their implementation.

Aerobic bioremediation of oil contaminated soil was investigated on laboratory-scale for purpose of pilot-plant installation. Mineral oil was analysed using IR spectroscopy. Sediment was qualitative analysed on GC/MS. Research also included microbiological analysis.

Spacial Plan of Serbia (Yugoslavia) predicts the concept of water supply, which is based on exploitation of water from surface storages, formed or under construction. Usage of surface storages is profitable if exploitation of water takes place by protected capacity, during predicted period. Useful spaces of storages are endangered by fulfillment with erosional material, especially in hilly-mountainous region. By the way, particles of sediment are the carriers of pollutants from agricultural surfaces and products of wet and dry deposition from the atmosphere. In order to protect storages by fulfillment, primary tasks are decreasing the erosion production and stopping the existing quantities of sediment in the hydrographic system. Data about investments in erosion control works (period 1994-2000) are presented in the paper. It is necessary to increase level of investments, because the territory of Serbia (Yugoslavia) is region of high risk, in the sense of erosional material production.

In order to carry out the program of protection and rational exploitation of Kovilj Marsh (Serbia, Yugoslavia), which is a part of special natural reserve called the Marsh of Kovilj and Petrovaradin, we have done an ecological analysis of the fish community. The research was conducted during the period of "low water", in the autumn 2000, on the following locations: Slajz, Tonja and Arkanj, and we have established the presence of 12 species from 6 different families. The saprobic index of the majority of bioindicative species shows that the water belongs to the beta-mesosaprobic type (the saprobic index according to Pantle-Buck is 2.1). The presence and abundance of certain ecological groups of fish is examined in relation to migration, type of food and type of substrate on which the fish lay their eggs. The results of this examination point to main features of certain localities in this floodplain, as well as to the necessity of taking appropriate measures of protection of this valuable water resource.