Protection of raw water quality at the water source is delicate and often very expensive. As it is known, the majority of hydrotechnical structures are complex and big in both technical and financial terms. This paper is aiming to show necessity to provide, if possible, multipurpose use of these structures in order to reduce and distribute the costs.

In this paper the results of zooplankton investigations (and its dominant group Copepoda) were presented from the part of the Boka Kotorska Bay with more intensive circulation with the open sea, from summer of 2005. Some results from the open South Adriatic were given, too - from the frontal zone exposed to anthropogenic eutrophication of Bojana and Drim rivers, and the impact of oligotrophic South Adriatic, simultaneously.

In this paper, results of phytoplankton investigations were performed in June 2005. The investigated positions are located near the entrance of Boka Kotorska Bay: two positions in the outer part (Zanjica and Mamula island) and two positions in the inner part of the Bay (Njivice and Tivat bay). In this area the influences of the open sea and the land are expressed to the phytoplankton community. As a consequence of that quantities of phytoplankton are lower in the outer part and higher in the inner part. The most dominant species is diatom Pseudo-nitzschia delicatissima which is very frequent in the eutrophic area.

Oil spill phenomena occur very often in the Boka Aquatorium. By studying the occurrence of oil stain on the sea surface the analyses of the Boka Bay pollution is represented in this document. Also represented is an evaluation or stimulation of expert opinion in a case of oil spill occurrence, in relation to the air temperature with the obvious consequences of carbon hydrogen appearance/presence.

Conventionally treatment method in potable water preparing, such as coagulation/flocculation, sedimentation and filtration has been shown reduction in efficiency of the contents of natural organic matter. There has been developed many alternative NOM removal technologies, in recent years. It has been made significant research effort in finding optimal drinking water treatment for NOM range reduction prior disinfection, that can minimise the formation of disinfection by-products and reduce the residual required to control bacterial regrowth in the distribution system, which is a consequence of coagulant with humic matter settling. Conventionally treatment modified by MIEX resin appliance meet the current water quality standards, with significant reduction of the coagulant quantity.

A great floristic variety has been noted according to qualitative analysis of phytoplankton. The presence of 187 taxa from 7 divisions of algae has been noted. The results of quantitative analysis show the dominance of centric diatoms. The high values of biomass that point out on the trophicity increase are noted on the strech from Nestin to Zemun (Serbia) with the maximum at Centa (Serbia) with 15,885 mg/cubic dm. Downstream Zemun, it has been noted gradual decrease of biomass up to Pancevo (Serbia), and afterwards downstream the considerable reduction all the way up to Brnjica (Serbia), where the value of algal biomass was 1,697 mg/cubic dm.

Phytoplankton composition of the Hydrosystem Danube-Tisza-Danube (HS DTD) and isolated peaks of chlorophyll a in summer months of 2003 and 2004 revealed moderate ecological potential in Banat and Backa region (Serbia). Investigated HS DTD water pointed out to a slighty better ecological potential in 2004.

This paper presents the results of the examinations of phytoplankton community of the Tamis river from March 2003 till December 2004. During the investigation it was determined 136 algal taxa from 6 divisions: Cyanophyta (10 taxa), Chrysophyta (1 taxa), Bacillariophyta (66 taxa), Pyrhophyta (4 taxa), Euglenophyta (14 taxa) and Chlorophyta (41 taxa). The contents and the structure analysis of phytoplankton as well as saprobiological valorization of water quality, has been carried out in the Republic Hydrometeorological Service of Serbia. Results of quality and quantitative analysis point to domination of Bacillariophyta and Chlorophyta. The index of saprobity given on the basis of Pantle-Buck method indicated that the quality of water of Tamis river on Jasa Tomic border locality belonged to beta and beta-alfa mesosaprobic category.

There are some water reservoirs on the territory of Zajecar district area (Serbia). Their purpose and time of building are very different. It is also different the organic matter production in those reservoirs. Water reservoirs for supplying with drinking water are very specific because the increased of organic products makes some difficulties in process of refinement reservoir water to drinking water. In this paper we are trying to explain, taking the reservoir Grliste for the example, if the biomanipulation exerts on water quality in the reservoirs.

Within the pollutant analysis in sediments the total organic carbon (TOC) content is determined, as well as nutrients such as nitrogen and phosphorus. In addition to this form carbon may be present as elemental or inorganic ones, as the crucial issue for sample preparation. Total phosphorus content was determined after sample digestion with sulphuric and perchloric acid. Organic nitrogen values were determined according the Kjeldahl method. Concentrations of TC, TOC, TIC, total P, organic N and total N in river Tisza sediment samples from sites Martonos, Novi Becej and Titel during 2004 and 2005 were presented.