In this paper there are presented the results of organic matter index, as dominant component of unsettled water of settlement, which after specified time locate into deeply karst underground appear on spring of river. Obtained results showed that into deeply karst underground has become to certain level of autopurification, which reflecting values of index this loading on the water of spring - river.

Since the water from the intergranular aquifer of Cemovsko Polje (Montenegro) represents an invaluable drinking water reserve, which can also be used for irrigation, the check up of the aquifer revealed that it is being infiltrated by pollutants from somewhere within the catchment area. The results have shown that the mentioned water from the intergranular aquifer (T3 and T4) is influenced by the agricultural activities in the area, leakage from the uncontrolled landfill of Podgorica, depending on the hydrological conditions, and, to a smaller degree, by the quality of the surface waterflows, with which it is connected.

Factors controlling of arsenic content in underground water are commented on the base of experimental obtained results of analysis of water quality from October to November 2006. The influence of water quality parameters and temperatures of water on examined locations of waterworks of middle Banat, south from Zrenjanin, public wells in Zrenjanin and waterworks north from Zrenjanin, on arsenic content is found.

Groundwater of Serbia is strategic natural resource which provides drinking water for about 75-80% of population. This resource is however not properly utilized and protected from pollution in accordance to its importance. Accepting to achieve the targets of EU Water Frame Directive, Serbia is in fact confirms the aim to better explore and protect the groundwater. The paper describes different activities planned under the project prepared in 2006 by the experts from leading Serbian institutions in water sector and in geology. Implementing this project until 2011 could create an ambience for future more sustainable exploitation and protection of the groundwater.

The salt pond Velika Slatina is the old meander of the river Tamis (Serbia). The ecosystem is periodically fill with moderate salt water. Phytoplankton production was 10 times bigger in 2003 than 2006. Ecological conditions were unfavourable for development of phytoplankton community. Diatoms show as the most abundant component in 2003, but euglenoids were in 2006, when bloom of Gloeotrichia natans f. bucharica Kissel was recorded. Results of biomass analysis also show dominant role of diatoms in 2003 and euglenoids in 2006.

The contents of heavy metals (Mn, Pb, and Cd) in water, sediments and shoots of emersed plants Phragmites communis, Typha latifolia and Typha angustifolia in the area of Bardaca fish pond were analyzed. Species Typha latifolia has shown the best ability for the bioaccumulation of heavy metals tested. Therefore, this species could be recommended as the phytoremediator of these pollutants from polluted waters. The results of this study indicate that the accumulation of tested elements in the water, and their availability to plants are still far from the critical level which may cause disturbance of balans in the Bardaca ecosystem.

Water quality in drainage canals system is under big influence of activities on surrounding agricultural land. In order to decrease transport and deposition part of plant protection chemicals and mineral fertilizers, vegetation belts with different shapes, characteristics and rules are possible to use. Besides the main purpose, this kind of belts are corridors for moving, but also place for living of wild plants and animals, what is increasing biodiversity. In that way, favourable conditions for organic agriculture in land reclamation area are possible to create.

In order to investigate the effects of wastewater from the Vrbas-Kula-Crvenka industrial basin on Grand Backa canal water quality, the water quality in the canal and the lateral canals which fall into the Grand Backa canal was examined, along with industrial water quality for ten of the most important polluters of those canals. A significant deterioration of Grand Backa canal water quality downstream of the lateral canals I-61 and I-64 was detected, as a consequence of waste water emission from the Vrbas-Kula-Crvenka industrial basin polluters. Data analysis has shown that two sugar factories are the heaviest polluters in the examined industrial basin.

In this paper the results of preliminary microbiological investigations of the canal Nadela water quality, done in order to determine level of pollution, are presented. Bacteriological analysis included the monitoring of quantitative composition of the organotrophs, presence of some physiological groups of bacteria and total number and fecal coliforms. Beside of that, level of water phosphatase activity and chlorophyll a concentration as important parameters of waterstate, were determined. Obtained results indicated low quality of the canal Nadela water and overload by organic matter, that cleary reflected negative influence of pollutants presents in that area.

Removal of colour by coagulation in the drinking water treatment is described. Optimal results are obtained by pH correction. Buffer capacity of raw water is dominant on efficiency and rentability of the process.