Microbiological monitoring of river water quality is obligatory for use-related aspects such as drinking water production, irrigation and recreation. Assessment of the microbiological quality of water and sediment at the Velika Morava River was performed at five sites, during 2010 and 2011. By applying standard procedures for sanitary correctness and organic load assessment, total of 16 parameters were analyzed. Results of analysis indicated that microbiological water quality of the Velika Morava River is unsatisfactory.

In the spring/summer and autumn season of 2010 dynamics of macrozoobenthos structure of Moravica River was investigated after the changes in habitat caused by floods. It was found that macroinvertebrates are represented with 13 groups and 64 taxa from 54 genera. Trichoptera fauna was represented by 11 species, Diptera 10, 8 Ephemeroptera, Odonata 5, 6 Oligocheata, Gastropoda 5, Crustacea 3, 2 Hirudinea, Bivalvia 2 and Turbellaria 1. In average 11 taxa was identified in samples. Most abundant were Gammarus pulex fossarum, Grammarus balcanicus, Asellus aquaticus and Chironomus thumma. Abundance of macroinvertebrates at the downstream direction was increasing and was correlated with decreasing number of taxa especially in the spring season. Species are equal in number to the initial sites, and downstream a smaller number of species dominated. Average value of N-index was 2.1 which points to relatively favorable structure of macroinvertebrates. Average value of C of 0.32 indicates increased dominance of individual species. Saprobity index ranged from 1.6 to 3.5 at average of 2.3.

Physico-chemical and microbiological analysis of Brvenica River water was conducted in period 2006-2010 and showed seasonal variations of water quality. The results of correspondence analysis indicated that the year 2006 regarding the physical and chemical characteristics of water, was different from the rest of the examined period. This year was characterized by the absence of ammonia, low contents of nitrite, iron and chlorine, and increased concentrations of KMnO4 consumption. In 2007 and 2008 presence of manganese in water, low concentration of KMnO4 consumption was detected as well increased turbidity and electrical conductivity. And the third distinguish period are years 2009 and 2010 when water was characterized by low concentration of NO3, and the presence of ammonia, NO2, and iron in the water, while turbidity was low and conductivity was average. In Brvenica River water Escherichia coli, Citrobacter sp., Enterococcus sp., Klebsiella sp. are detected. In year 2006 number of aerobic bacteria and total coliforms were rather low, while their number in 2008 is relatively high. Over the whole period, only in 2008 fecal streptococci were not detected. Other years are characterized by growth of aerobic bacteria and total coliforms and the occasional presence of fecal streptococci. Throughout the whole examination period fecal coliform bacteria were present in the water.

The research of benthic fauna was done in part of the River Temstica, the right tributary of Nisava. Sampling was conducted on four sites, between 10 and 18 July 2010. Quantitative and qualitative analysis revealed the presence of eight groups of macroinvertebrates. The most frequent groups were Diptera, Ephemeroptera, Plecoptera, Trichoptera. Lower presence was shown by the groups of Coleoptera, Chironomidae, Turbellaria, Hydracarina. The greatest species diversity was characterized by order Trichoptera, while the largest number of individuals was characterized by order Diptera. There has been stated a 10 new taxa for this aquifer, with a new taxonomic group – Hydracarina. It is necessary to conduct further research of this river, with a need to analyze more samples from several locations (to conduct a research of the entire river, including the river mouth), and through the annual seasonal dynamics.

This paper presents aquatic macroinvertebrate community composition at six investigated localities of Drina River. Sampling was performed during 2004. Field data together with characteristics of the community were used to estimate the status of the river. According to our results good water quality, within the limits of the 2nd category, was evaluated for Drina River.

Research macroinvertebrates in the lower reaches of the River Veternica was conducted during 2008 in spring and summer season on nine sites, in period of reduced outflow of water from the Lake Barje, when the water level is often reduced to the biological minimum. The presence of 91 taxa from 13 groups of macrozoobenthos was detected. Groups of Diptera, Ephemeroptera and Trichoptera were presented with 18, while Megaloptera, Plesoptera and Nematomorpha with one taxon each. The spring has been allocated 69 and 70 taxa in summer. The average was separated 17 taxa. Average number of macrozoobenthos was 1440 ind/square m per site. The few types of macroinvertebrates were very abundant at the site before the river confluence into the South Morava River. Insects made up 66.4% of the total number of individuals, especially the numerous groups of Diptera with 45.7%, while the share of the group Aquatic amounted 31%. The largest shares of the total abundance of taxa were as follows: Chironomus thumma with 28.16%, Limnedrilus hoffmeisteri with 11.2% and Tubifex tubifex with 6.89% and Caenis macrura from 5.2%. The structural parameters indicate that diversity of macrozoobenthos reduces in downstream direction, reflecting degradation of ecosystems.

The analysis of the frequencies of chromosome breaks and gaps on the pike - Esox lucius L. individuals from different locations collected in two consecutive years, were showed the highest values that were above the level of spontaneous (under the level of 3%) changes. Frequences of changes in fish Esox lucius L. were higher than the level of the presumed critical zone (3.0-3.5%) at locality of Danube by Visnjica and within the zone by Grocka. In consecutice years in river Tamis by Pancevo, both obtained values of chromosomal changes in this fish also were above the critical zone. Physicochemical water analyses were shown high level of organic contamination and concentration of phenols above MDK values for the 1st, 2nd water categories which argued obtained cytogenetic results. The localities obviously has a risk of being permanent or periodical contaminated with genotoxic agents.

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).