In this paper the short review of the results of calculation of the coincidence between the water level and quality parameters at the gauging station Cuprija-rail bridge (Serbia, Yugoslavia) is presented. The basic principles of the applied method and criteria for the estimation of the statistic significance of coincidence indicators are given. At the end of the analyses and comments of the obtained results, as well as the possibility for application of this methodology are given. The paper gives numerical quantities of the estimated indicators of statistical significance of the coincidence of water level and quality parameters of groundwater. Also, the graphical illustration, which shows the common exceeding probabilities of the water level and quality parameters, is presented.

In this paper a part of results of the wastewater quality control from the Thermal Power Plant "Kostolac", water from the rivers Danube and Mlava, and groudwaters near by (Serbia, Yugoslavia), is considered. In order to protect environment from the effects of hurtful substances make during working process of Thermal Power Plant "Kostolac" is especially does using solid fuel (coal), the Institute of Public Health of Serbia following an approved program checks upon the quality of groundwaters, water the rivers Danube and Mlava including the wastewater from the Thermal Power Plant "Kostolac", four times a year. The results of our research point out to the hurtful effects of the wastewater from Thermal Power Plant "Kostolac" on the groundwater.

The results of the determination of PCB (polychlorinated biphenyls) residues by gas chromatography, in the samples of underground water of one alluvial well of the river Danube (Serbia, Yugoslavia) have been presented. The residues of PCB (polychlorinated biphenyls) in examined samples (February-March period, 1997) were detected.

Removal of natural organic matter (NOM) from groundwater by aluminium sulphate and polyaluminium chloride (PACl) was investigated. The maximal decrease of UV absorbance at 254 nm was near 70%. Decrease of permanganate value about 50% was achieved by PACl coagulation. Similar effect can be achieved using 2.5 fold higher concentration of aluminium sulphate. Coagulation process at pH 5.5 was successful with 3-5 times less concentration of coagulant. The heterogenous composition of NOM in water had been changing by coagulation. The total trihalomethane formation potential is 50-60% lower in coagulated water. The greatest removal was success for chloroform precursors.

Removal of natural organic matter from water was investigated using granulated activated carbon. Groundwater from northern Banat region (Serbia, Yugoslavia) was used. Samples of raw water and water after coagulation were ozonated and than GAC adsorption was performed. The investigation was carried out under the static conditions to determine the GAC adsorption capacity and kinetic coefficients.

The work is concerned with the study of groundwater quality in respect of hydrocarbons content, carried out on several sites on the territory of the Oil Refinery Novi Sad (Serbia, Serbia&Montenegro). In the course of four year that elapsed since the time spillage of crude and oil derivatives and deposition of burning products on the Refinery soil (April-June 1999) the processes of passive in situ bioremediation have been taking place on the contaminated area. By comparing the results for three contamination zones in a circle of 270 m from the site at which the spillage occurred, a certain increase in content of mineral oil was observed in deeper water-bearing layers at a distance of 200 and 270 m from the spillage site. A content of BTEX components the "movement" of the pollution was observed from the close zone 1 via the farther zone 2 to the farthest zone 3, which indicates that the intensity of bioremediation and all physico-chemical processes in general, taking place on the pollution site, is not sufficient to prevent pollution spreading. The assumption that the zone in question in probably a limiting zone is based on the results of the fourth sampling campaign, in which BTEX components were not detected on any of the locations of the zones 2 and 3.

The process of removal of natural organic matter from groundwater by adsorption on powdered activated carbon, coagulation and flocculation was investigated. It was found that the combination of these processes yielded a decrease of KMnO4 values, which allowed the reduction of the coagulant concentration, needed to achieve the necessary quality of drinking water, up to 50%. Also, it was established that the sequence of adding powdered activated carbon and coagulant is one of the essential factors determining the efficiency of NOM removal from water, and which is primarily conditioned by the nature of the organic matter present in the investigated water.