The paper deals with pilot-scale investigations of the effect of preozonation on NOM removal from groundwater by coagulation and flocculation processes. It was found that the preozonation increased the efficiency of organic matter removal by coagulation and flocculation from 23.6 to 47.2% as judged on the basis of KMnO4 values. From the aspect of the change of content of trihalomethanes precursors preozonation exhibits both the positive and negative effects if their content in the water after coagulation is considered in dependence of the applied ozone dose. The obtained values siggest the necessity of careful optimization of the processes of preozonation, coagulation, and flocculation, especially from the aspect of the change in content of the precursors of disinfection byproducts.

According to Water Plan of the Republic of Serbia the area between Kovin and Dubovac was marked as a possible place for water source for regional water supply of towns and industry of South Backa Region (Serbia). Commencement of underwater coal exploitation was at the beginning of 1990's in the Danube riparian zone near Dubovacka Ada. Potential influence of long-term underwater coal exploitation from "Kovin" trial coal pit on Dubovacka Ada on quality and quantity of groundwater that will be extracted from regional water source is analysed in this article.

The town Pozarevac water supply is endangered due to groundwater quality degradation on the only remaining water source Kljuc 1. Nitrate content presents critical parameter (MCL in potable water is 50 mg NO3/l) with values in cumulative samples up to 40-45 mg NO3/l, locally up to 70-100 mg NO3/l. Rapid water quality degradation on water source in the last few years is a consequence of the surrounding activities which have influenced on quality deterioration, excessive groundwater extraction, off-line of water source Meminac, unfavourable hydrologic conditions etc.

Concentrations of nitrate above defined levels for portable water are present in most of the groundwater sources in Velika Morava river alluvion. Some problems exists in Meminac and Kljuc, groundwater sources of Pozarevac town. Some detail investigations were organized in 2002. Survey of groundwater quality in the wide surrounding of Kljuc confirmed some earlier made assumptions about influence of agriculture and sewage water, and their contribution to existing groundwater quality.

The paper deals with determining the dependence of trihalomethanes forming (chloroform, bromdichlormethane, dibromchlormethane and bromoform) on the contents of natural organic matters from groundwater. The analyses was made bay calculating correlation of trihalomethanes forming potential (THMPF) with UV absorbance and permanganate number as surogates parameters for defining in content NOM in water. These were used to observe the changes in the content of organic matters after coagulation. A good correlation of THMPF, PF chloroform and UV absorbance (254 nm) (coeficient of correlation 0.72 and 0.87) was observed as well as a good with UV absorbance (254 nm) (coeficient of correlation - 0.88) and with PN (coeficient of correlation - 0.80) in coeficient of correlation in bromated trihalomethanes forming.

As a consequence of bombing of Novi Sad Oil Refinery, Serbia (Serbia&Montenegro), the spillage of large amounts of oil and derivatives caused hydrocarbons pollution of the area surrounding the Refinery and the river Danube, thus directly endangering the entire water source "Ratno ostro". As a measure of protection in the division zone of the Refinery and the water source area, a hydraulic barrier was constructed. Within the process of monitoring piezometer water quality and the water supplied by protection system wells, microbiological analyses of water were carried out with the aim of supervising the barrier functioning. The results have shown that bacterial populations in polluted areas exhibit a duel role: they act as bioindicators of a certain pollution, but at the same time they take part in the process of selfpurification.

Degradation of groundwater quality whish is used as a raw water source, caused by the continuous pollution, develops gradually. Therefore, it is necessary to analyze the pollution influence, on the first place by the expect concentration of hazardous substances in groundwater. Water source protection measures are based on the results of these analyses.

Water quality examination of water source Zagoric, was conducted with aim to determine water quality on the bases of physico-chemical parameters, in dry and rainy period. Water supply system in Podgorica scopes several water supply sources out of which Mareza and Zagoric have the greatest capacity. The aim of this study was to determine hygienic quality of water in operational and dug wells on representative locations in flow areas, and on the basis of obtained results to estimate its influence on population health.

Processes like QMS (Quality management systems) and EMS (Environmental management systems) consist of series of procedures/elements, among which are operative or working procedures. One of these procedures is control of waste waters from the Aluminium Plant in Podgorica, Montenegro (Serbia&Montenegro). This procedure controls the order of activities, the responsibility, the input and output documents, with the exclusive aim to measure the effects of protection of surface and underground waters and to review the EMS of the company for the waste waters.

The paper presents main recommendations for monitoring groundwater from the aspect of the EU Water Framework Directive. It is concerned with some basic notions of monitoring of quantitative and chemical state of groundwater. It is pointed out that the network of gauging stations must be planned for every catchment area, to ensure a holistic and all-encompassing survey of the chemical state of groundwater, and allow detection of long-term anthropogenic effects of pollution. In addition to usual numerical and graphical presentation, the state of groundwater quality should be also presented by colours: good state - green, bad state - red.