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.

Forest ecosystems are important component of environment and row basis for wood processing industry. Traditional attitude about primate of productive functions in relation to useful functions, is under question, due to next reasons: exhaustion of sources of wood mass; affirmation of protective and regulative functions in domains of water-supply and erosion control. This attitide os represented in basic plan documents in Serbia, as well as in European Union. Protection, care of existing, and restoration of degraded forests, are the possibilities for development of high-profitable activities such as: recreation and sport tourism, hunting tourism and healthy food production.

According to existing national Standard for drinking water quality NO3 sup(-) ion is limited to 50 mg/l. Removal of NO3 sup(-) concentration greater than this limit is necessary. One of the possible methods is biological denitrification with CH3OH. Principals of this method are described in this paper with recommendation for construction of pilot plan on the specific groundwater source.

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.

Importance of sediments quantity and quality problems addressing to land reclamation canal network in Vojvodina (Serbia, Serbia&Montenegro) are pointed out in this paper. Necessity for sediments monitoring and criteria definition for environmental discharge are drown. Special attention is paid to agricultural land as recipient of these sediments.

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.

This paper presents the results of investigation on photosynthetic pigments, chlorophyll a in the river Danube (Serbia) during 2002-2005. Field investigations were carried out with seasonal dynamics on the river strech between 1112 and 851 km. Exceptionally in September, during low water period, investigations were carried out on the river strech between km 1260 - 851, including the main tributaries: Tisza, Sava, Velika Morava and Pek. The concentrations of chlorophyll a and phaeophytin a were determined using the standard ISO 10260/92 methodology, variant B. Pigment extraction was done in hot ethanol immediately after sampling, on board of a research ship. The results revealed seasonal concentration dynamics of the mentioned indicators of primary productivity and physiological status of the algae community where fall of chlorophyll a from the upstream towards downstream profiles was evidenced.

Recent surveys of river Tisza (Serbia) have shown that class Oligochaeta is commonly present as dominant member of benthic macroinvertebrate community. Knowing the fact that this class is very good indicator of organic upload in aquatic ecosystem, in this paper it is used for saprobiological water quality assessment of middle and lower stream of river Tisza in summer of 2002, 2004 and 2005. Results presented as saprobiological indices, showed that water quality of river Tisza (Serbia) was alfa-mesosaprobioc (the third class) during research period.