In Laboratory for examination of waste waters in Belgrade sewerage system many analysis are being done to indicate the physical, chemical and biological characteristics of waste waters. Biochemical analyses which are being done include two parameters: biochemical oxygen demand (BOD) and newly introduced parameter index of phosphate activity (IFA). Determination of IFA is relatively fast biochemical method which can, within few hours, give information of present organic pollution and its results could be applied for categorization of waters. Analyses were conducted during 2008 and according to the results waste waters mainly belong to the 5th category of water, more, the examined waste waters were out of all water describing categories.

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.

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.

Environment is subject of changes in the presence of aquatic pollutants which increase synthesis of biotransformation enzymes and elicitate oxidative stress in aquatic organisms. Monitoring changes of quality of aquatic ecosystems could be based on watching certain biomarkers, like biochemical, molecular and physiological responses of aquatic organisms after exposure to organic toxicants.

Lake ecosystems determined by trophic conditions, accurately defined Ecological status of protected area. Trophic condition of water of Lake Skadar and two rivers, the inflow Moraca and the outflow Bojana was described via plankton data considering abundance of phytoplankton, seasonal dynamics of organotrophs, cyanobacteria, total coliforms, plankton biodegrading potential and nitrogen fixing bacterioplankton. The trophic potential for phytoplankton growth has been detected in late autumn throughout September-November 2004, contrary to early summer June-July 2005, and adverse growth of bacterioplankton in May, June and September 2005, respectively. The results of quantitative analysis of coliforms showed good relation of Lake Skadar and Ada Bojana, contrary to similarities between Moraca River and Ada Bojana estimates in accordance with the Pantle-Buck index. Nevertheless, investigation pointed out Lake Skadar beta-mesosaprobic level and moderate self-purification rate. In evaluating trophic conditions the good ecological potential of protected area has been proposed.

This paper presents results of measuring the contents of certain bioindicators in samples of digestive gland and lung of mussels (Mytilus galloprovincialis). The results were obtained in the framework of the Program for monitoring ecological status in Montenegro from 2009 to 2011 year. Samples were collected from two locations: Kotor-Dobrota (wild mussels) and the site of Bijela (caged mussels). Dynamic of sampling was twice a year, in April and September. In order to estimate the spatial distribution and temporal trends of pollution the results were compared with analysis of biomarkers in the three localities in the Slovenian coastal waters (bays Piran, Koper and Strujan). Biomarker responses showed no differences between these positions in the southern and northern Adriatic.

The aim of this work is to present the water quality of littoral zone of lake Prespa, based on defined physico-chemical parameters (NO3, NO2, NH3, total nitrogen). Samples for analysis were collected with a monthly dynamics during 2007 year (April-December). This period is not chosen by chance, in regard to that the lake basin is constantly under the anthropogenic influence and climate changes that have been registered by this time. According to the obtained results of the performed analyses, basis of the water act of RM and OECD regulation, a categorization of the after was made in the respective measuring points.