The allochthonous aquatic macroinvertebrates and fish species represent a potential danger to the autochthonous diversity. Hydrobiological research conducted during 2008 under the development of medium-term programmes for fishery improvement in Serbia, showed that some of the allochthonous aquatic macroinvertebrates and fish species have expanded their areals to a new water habitats. Artificial lakes (reservoirs) proved to be very suitable for the population of allochthonous species, where they become numerous most of the time. New habitats were found for allochthonous aquatic macroinvertebrates species: shells (Dreissena polymorpha, Sinanodonta woodiana) and American crab (Orconectes limosus), and for fish species for Micropterus salmoides. It was also determined that fish populating is a good way to inhabit and expand new habitats with allochthonous species of aquatic organisms.

The Bovan reservoir is built on the river Moravica, near Aleksinac (Serbia), primarily for the purpose of water supply. Investigations were carried out during the period of June 2005 to December 2006, with the aim to determine the quality of water, the composition, spatial and time dynamics of communities of microorganisms. The results showed that according to the total number of bacteria in the water reservoir Bovan fall into the category of clean water by Amrazena (1976). By Kohl (1975), water reservoir Bovan belongs to class 2. Summer-time give maximum water characteristics the 2nd-3rd class. Index T/H varies from category to category moderately contaminated clean water. Values heterotrophs percentage representation in the total number of bacteria indicating the great burden of water organic matter.

Content of arsenic in groundwater form south Banat which are used for water supply of local population was determined. 228 wells were analyzed, and for arsenic determination was used atomic apsorption spectrometry - graphite furnace technique (Perkin Elmer Analyst 700). Arsenic is detected in concentrations over 10 microgram/l in several locations: Pancevo (water supply Filter Stanica, Gradska Suma, OB, and in part of water supply Sibnica), Kovin, Dubovac, Idvor, Veliki Gaj, Glogonj, Sefkerin and part of Sakule. The lowest concentrations of arsenic are detected in the territory of Deliblatska Pescara and municipalities of Vrsac and Bela Crkva.

Anionic clays (layered double hydroxides) comprise positively charged layers with at least two different metal cations, octahedrally coordinated by hydroxyl groups. The positive charges of layered double hydroxides are counterbalanced by interlayer anions. The interlayer anions and water, which fill the interlayer space, are often labile. Therefore, anionic clays exhibit anion exchange capacity (AEC). Anionic clays which have a high surface area and a high anion exchange capacity, are potential adsorbents for anionic contanimants, such as the oxyanion of chrome. The adsorption study of chromium (VI) from aqueous solutions by natural cationic clay mineral (kaolinite, montmorillonite, etc.) was not given much attention, perhaps due to the fact cationic clays have negatively charged layers and clay mineral surface shows no affinity for oxyanion of chrome.

Arsenic speciation can be very important in analysis of water, foodstuffs, and environmental samples, besides of total arsenic analysis. Hydride generation atomic absorption spectrometry can be used for speciation analysis based on different hydride generation condition. In our work, we studied effect of L-ascorbic acid like the reaction medium and the prereducing agent.

Groundwater from the middle Banat region (Serbia) which is used as a drinking water supply for Zrenjanin town contains a high amount of natural organic matter and a high content of arsenic. In this study a pilot-scale system was used to investigate the influence of different ozone doses (0.4-0.9 mg O3/mg DOC) during a pre-ozonation process on NOM removal by coagulation. Ferric chloride coagulant was chosen at a dose of 100 g/cubic meter, as a traditional coagulant which can also help in arsenic removal. The obtained results indicate that an ozone dose of 0.4 mg O3/mg DOC has the best influence on structural changes of NOM. The coagulation process with ferric chloride as coagulant had a significant influence on the arsenic content of the water, with the measured values in the water after coagulation in all three investigated treatment trains being below 10 microgram/l, which is the standard MCL in Serbian legislation.

In the paper is presented the microbiological quality of groundwater of drinking water supply Strand which is important water source for the city of Novi Sad (Serbia). The examinations were carried out using high and low nutritive media. The count of physiological groups, that are relevant from the aspect of organic pollution and phosphatase activity were also monitored. The results indicate potential organical pollution and need for protection of the water supply Strand.

This paper presents the concentration of Pb, Cd, Zn, Cu and Ni in the surface sediment samples, determined by EDPXRF. Also, a horizontal distribution of these metals is given for seven investigated sites in the coastal sea of Montenegro, from the entrace to the Bokakotorska Bay to the mouth of the river Bojana. A trend of increase in the concentration of metals with the distance from the coast is noticed in the studied area. The possible causes of this distribution should be sought in the direction of movement of sea currents in the Adriatic Sea as well as the fate of suspended material after entering the river Bojana.

In the present paper it is presented application of Daily Egg Production Method (DEPM) to the anchovy (Engraulis encrasicolus L. 1758) stock in the open part of Montenegrin coast. This article is based on the research done within the frame of AdriaMed Project.

A batch adsorption test was conducted to examine the adsorption characteristics of cadmium and copper on bed sediments of the Sava river and its relation to the concentration of dissolved metals. The adsorption of ions were studied using equilibrium technique as a function of adsorbate concentration. The adsorption data, over the whole range of concentrations used, follow the Langmuir adsorption isotherm. Cu2+ and Cd2+ adsorption isotherms were measured on some sediment samples obtained from 3 different sites.