A simple approach for ranking the leaching of pesticides from surface soil presented and tentatively calibrated with field data from an agricultural a The approach is based on the calculation of a leaching index indicating the proportion of active ingredient, with respect to the quantity applied, leac from a soil model in a given time interval (one year). In the selected area wells tapping an unconfined aquifer were sampled for groundwater pesticide residue analysis, in order to explore the index region between leachers and nonleachers.

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.