The weekly measurement of physico-chemical and biological parameters was done during the spring of 2008 in order to assess the level of eutrophication in the Kotor Bay. Chlorophyll a was used as trophic level indicator and its values varied from minimal 1.00 mg/cubic meter in June on the depth of 10 m to maximal 3.71 mg/cubic meter on the sea surface in May. According to Nixon criteria during investigation period it can be concluded that the area in question is oligotrophic. On the other hand, according to UNEP criteria which are somewhat stricter when the concentration of chlorophyll a is in question, Kotor Bay was mesoeutrophic area.

Zooplankton community analysis was conducted for spring (April - 07) and summer (August - 07) in Boka Kotorska Bay. Analyses included determination of biomass and qualitative composition. Data are given on the number of specimens per cubic meter as well as on the volume organisms. Qualitative composition showed domination Copepoda of zooplanktons groups.

The paper shows available water resources potential of karsts spring waters of Carpatho-Balkan region of east Serbia. Basic elements of water balance are also given, as well as quantitative indicators of low flows. Karsts spring yield is compared to the domicile waters of Serbia. We can also read certain comments and see an estimation maximum usage of these karsts waters.

This work shows the effects of opening the Itebej sluice gate on the metals content of the water and sediment of the Begej canal. A deterioration in water quality resulted, in particular on the first day after opening of the sluice gate, when high concentrations of Zn, Cr, Cu and Pb were detected. The metals content of the surface sediments across the canal at Klek had significantly higher concentrations of Pb, Cr, Zn, Cu and Hg five days after the opening, whereas there were no obvious changes at Itebej. From the metals content of the suspended sediment it can be concluded that the increase in metals contents occurred one day after opening the sluice gate.

Relatively dense network of irrigation channels in Vojvodina is exposed to various point and non-point pollutants impacts. Therefore, deposited channel sediments-sludges can be contaminated with high concentration of dangerous and harmful substances such as polycyclic aromatic hydrocarbons (PAH). These sediments could have long lasting harmful effects on environmental status, quality and usability of channel water, and especially on surrounding agricultural soil, where dredged sediments are deposited or scattered. In this paper above mentioned conclusions are illustrated by quality analysis of specific irrigation channels sediments in terms of PAH contents in them.

Due to drainage as a significant measure of land reclamation, large part of Vojvodina Province (Serbia) affected by excessive water could become an agricultural land. The stability of ecosystems could be decreased by degrading the biodiversity. Additionally, Vojvodina has cca 6% of sylvan landscape but according to documents of spatial arrangement planning that area should be 14%. In order to solve this problem the implementation of biological measure could increase drainage efficiency by improving biodiversity and increasing the area covered by sylvan landscape, which is likely to do using biological measures of drainage on low productivity areas and buffer strips along canal network.

During field research of phytocenic characteristics of the river Moravica flow and the influence of anthropogenic pollution, the presence of the following hydro-phytic biocenoses has been established: Floating macrophytes ass. Lemnetum minoris Oberd. 1960 and submersed macrophytes Myriophyllo-Potametum Soo 1934. Based on physicochemical water analyses and ecological indexes, these biocenoses belong to transitional group of mesotrophic and eutrophic biocenoses which develop in water highly saturated with mineral substances (highly polluted waters). Biocenosis Lemnetum minoris with differentiating species Lemna minor matches - meso - saprogenic waters. These biocenoses grow in both mid and upper river flow.

The paper presents aquatic macroinvertebrate community composition at six investigated localities of the Veliki Rzav river (Serbia). Sampling were carried out during 2005. Characteristics of the macroinvertebrate community with field data were used to estimate the status of the river.

Water quality monitoring of surface waters encompasses the watercourses of the river basins of Una, Vrbas, Bosna, Drina, Ukrina and the direct Sava basin. Apart from comprehensive analyses which demand determinations of physical - chemical characteristics, as well as the ihtiofauna composition, special emphasis is given to the analysis of the macrozoobenthos. As a part of all water ecosystems, benthic invertebrate serve as a reliable indicator of the quality and changes of the environment, due to a series of advantages in relation to other communities. Most of the aquatic habitats, especially flowing waters of good quality of water and benthic state, enable various of benthic invertebrates communities with moderate formation of species within the overall number of the present individual species. This kind of communities react to possible changes in the community composition (abundance and macroinvertebrata composition).

In the scope of complex water quality analysis of the Bocac reservoir, as well as rivers which flow into and out of the Bocac reservoir (Vrbas, Crna Rijeka) during the period from May to September 2008, the contents and the dynamics of the phyto and zooplankton were analyzed as biological parameters. The qualitative contents of the phytoplankton includes 5 divisions of total 27 taxa from 16 species; the tributaries contain 30 taxa from 19 genuses. The zooplankton (Rotatoria, Cladocera and Copepoda) contain 22 taxa from 16 genuses; the tributaries contain 32 taxa from 19 genuses with huge dominance of the Rotatoria species. By saprobiological analysis, species of oligo and beta mezosaprobiological character previal.