In our previous papers, it is concluded that wood sawdust can be applied as adsorbent for heavy metals removing from water. All earlier investigations are done in batches, while it is confirmed that different heavy metals are adsorbing with various efficacy on sawdust of different kind of wood. Adsorption of copper ions from model water is investigated in this paper, by its passing throw column filled with poplar and fir sawdust, granulation in the range 0.5-1 mm. Starting concentration of copper ions was the same in all experiments, and flowrates of model water and column geometry are varied. Certain volumes of water are taken on the column outlet, and copper ions concentration are determinated in this samples. On the basis of these results breakthrough curves are obtained, and adsorption parameters in dynamic conditions are determinated.

Removal of natural organic matter from water was investigated using granulated activated carbon. Groundwater from northern Banat region (Serbia, Yugoslavia) was used. Samples of raw water and water after coagulation were ozonated and than GAC adsorption was performed. The investigation was carried out under the static conditions to determine the GAC adsorption capacity and kinetic coefficients.

In this investigation the applied method for lead determination in traces, from 10E-6 - 10E-10 mol/cubic dm, was Potentiometric Stripping Analysis (PSA). The main attribute of this method is possibility to detect very low metal concentrations. The investigation results of level concentration of lead into the top, natural and atmospheric water from some towns of Serbia (Yugoslavia), including city of Belgrade, are given. The investigation was carried out in some towns of Serbia (Yugoslavia), including city of Belgrade, during the 1994-1995.

Activities of rat brain synaptic plasma membrane (SPM)Na(+)/K(+)-ATPase and Mg(2+)-ATPase were investigated by in vitro individual and simultaneous exposure to ions of the first transition series metals (Cu(2+), Zn(2+), Fe(2+)). All investigated metals produced a larger maximum inhibition of Na(+)/K(+)-ATPase than Mg(2+)-ATPase activity. Metal concentrations causing 50% inhibition of Na(+)/K(+)-ATPase activities were: Cu(2+) 7.1 microM Zn(2+) 19 microM Fe(2+) 25 microM. Simulataneous exposure to metal combinations: Cu(2+)/Zn(2+), Cu(2+)/Fe(2+) and Zn(2+)/Fe(2+) inhibited both the Na(+)/K(+)-ATPase and Mg(2+)-ATPase activity synergistically, i.e., more than the sum of the metal induced inhibitions assayed separately. It is also established that the plot of logarithm IC50 values of Na(+)/K(+)-ATPase activity vs. the ionic radius of (Cu(2+), Zn(2+), Fe(2+)) is a straight line that enables to predict the value IC50 for other metals of the first transition series. The results obtained show that Na(+)/K(+)-ATPase is promising as a biological component of biosensor.

During three years period from 1991 to 1994, investigation of the river Kolubara (Serbia, Yugoslavia) was carried out along 35 km of water course from Valjevo to Lajkovac. The macrozoobenthos community was composed of 117 determined taxa. Of the found taxa Oligochaeta were the most diverse with 40 taxa determined. The greatest diversity of macrozoobenthos community was foound at the river section in Valjevo, upstream the mouth of Gradac (69), while the community was most uniform downstream Valjevo at Bela Stena (24 taxa). A decrease as well as an increase in the macrozoobenthos diversity was not in accordance with similar decrease or increase in saprobic index values since they were in narrow range from 2.37 to 2.59.

According to microbiological parameters, waters of both small rivers of eastern Backa, Serbia (Yugoslavia), are slightly and moderately polluted by organic matter at the most of the investigated localities in summer season. The satisfactory power of water selfpurification has been preserved in these aquatic ecosystems. In order to prevent further eutrophication processes, certain measures of river water protection and conservation should be undertaken, especially in stagnant parts of investigated waters. Also, the regular monitoring of water quality should be established.

In this paper, some data on long term seasonal investigation of hydrography and plankton are presented. The most important fact is that the whole area is exposed to the impact of the freshwater from numerous sources from the coast and submarine springs in Boka Kotorska Bay, as the impact of rivers Bojana and Drim. Exchange of the intermediate water-masses between Adriatic and Jonian basins is of great importance, too. So, basic ecological data, as well as characteristic phytoplankton and zooplankton groups and species are described.

Some new results of the monitoring and control of the sea-water quality along the Montenegrin coast of the Adriatic sea, Montenegro (Yugoslavia) are presented. The recent data from summer 1998 are compared with some previous results. So, increasing of temperature mean values and decreasing of salinity and sea-water density were found in comparison with the previous years in the whole investigated area. At the same time, the quality of the sea is growing worse, step by step. Faster changes were found in Boka Kotorska Bay, Montenegro (Yugoslavia) than outside of the bay, in the zone which is exposed to the stronger influence of the open sea. Finally, the most essential conclusion is that the solution of wastewater discharges becomes more and more important, especially in semienclosed Boka Kotorska Bay (Adriatic Sea, Montenegro, Yugoslavia).

Expert system (ES) is a software which unites mathematical models, empirical knowledge, expert evaluation, engineering intuition, heuristic rules and necessary informations which through the inference engine gives useful advise to the decision maker, to reach a correct and timely decision. The objectives of ES cover a wide range of tasks of protection of waters, out of which the following seem to be the most important: diagnostics, monitoring, estimation, interpretation, planning and design of systems, maintenance, trouble shooting, education, management.

The results of long standing and systematic monitoring of quality of river Danube's water, done by the net of stations for controllingquality of water of the Republic Hydrometeorological Service of Serbia (Yugoslavia) are given in this paper. The amount of organic matter (HPK, BPK5), concentration of dissolved oxygen, nutritive matters (NH4(+), NO2(-), NO3(-) and total PO4(3-) and conductivity are specially examined. The results are shown depending on seasonal measuring (average values for spring, summer, autumn and winter) during the period 1995-1998, and the changes are analyzed.