Composition of benthic macroinvertebrates and phytoplankton were examined during the period of July-November 2006, for purposes of freshwater quality assessment in protected area of Jegricka water body. Results of research show intensive sedimentation of organic matter in river bed, which is caused by eutrophication processes and small flow velocity in this canalized river of Vojvodina.

This paper presents the results of the Danube river water quality analysis, using the data set for the period of 2001-2005, provided by the Hydrometeorological Service of Republic of Serbia. Main input parameters - data on water quality resulting from sampling performed generally once per month for relevant parameters, are used according to Water Quality Index (WQI) methodology. Data grouped on a sampling site basis, averaged on a yearly level, resulting with a median WQI of each sampling station are employed to create a synthesized quality indicator. Final result of such an analysis shows a general deterioration of quality expressed using WQI for the observed period.

Scarce natural resources which are important for development of society or civilization itself are the issue of research for economists from the point of view of their efficient utilization. Theory of natural monopoly asserts that for society is better to treat scarce resources as monopoly than to put them on free market. The assertion is that it is better to invest in development of other markets than into free competition in sphere of some scarce resources. Main aim of this paper is to overview some elements of theory of natural monopoly.

One of the biggest problems in drinking water treatment is the presence of a high natural organic matter (NOM) content in water resources. This paper presents the results of a study which aimed mainly to determine a combined coagulation and preozonization process application for trihalomethanes and haloacetic acids precursors content in ground water rich in natural organic matter.

This work considers the possibility of enhancing the iron (III) chloride coagulation process in natural organic matter removal by flocculation sludge recirculation. The results show that flocculation sludge has the potential to coagulate organic matter, and shows a dependence on the depth in the precipitator (0, 30 or 70 cm). Recirculation of flocculation sludge at a dose of 1.6 g/l (from a depth of 30 cm), results in a reduction of required coagulant by 25%.

Iron-related well-screen encrustation and aquifer biofouling has decreased the specific capacity of RB-7 well. This paper describes the role of iron-related bacteria in the encrustation process and relates their occurrence to chemical conditions in the well.

Filamentous bacteria are commonly found in activated sludge. If numerous, they can cause bulking problems. In order to control their number in a system detailed identification of filaments is necessary. In Subotica Wastewater Treatment Plant (WWTP) daily analyses of filamentous bacteria were performed from January 2006 till March 2007. The dominant and constantly abundant was Thiothrix sp. The filaments of Haliscomenobacter hydrosis and Type 1863 were also common (moderately numerous with periods when develop massively). Nostocoida limicola was frequent, but not numerous. Sphaerotilus natans was numerous in some periods when even dominant. Type 1701, Beggiatoa sp. and nocardioform actinomycetes were rarely found and were not abundant.

Sea urchin gametes, embryos and larvae can be used for quick, cheap and reliable screening and testing of pharmacologically active substances and pollutants. The results obtained are in many cases applicable to mammals including humans.

Sea urchin, Paracentrotus lividus belongs to Echinoderms and has wide distribution as well in Meditarranean Sea as in the Adriatic Sea. It is very appreciated as object for testing negative impact of pollution, so can be used as bio indicator of sea water and sediments quality. Identification of the presence of this animal is done at 11 locations inside the Bay of Boka Kotorska (Montenegro), during 2005/2006. Obtained results show that the sea-urchin inhabit only outer part of Boka Kotorska Bay, where is open sea impact very strong, while inner part of the Bay is characterized by absence of Paracentrotus lividus, what can be caused by potential low quality of the sea water in the Bay.

In Serbia, in the most cases, drinking water supply is based on alluvial sources. The appearance of nitrate in some important alluvium aquifer has been observed and an increasing of this problem can be expected with a currently tendency for intensifying the agricultural production. Therefore, the used techniques which are able to identify the source of nitrate in groundwaters and existing processes of its reduction will be more and more requested. Simultaneously determination of both nitrogen and oxygen isotopic fingerprints allows us to make a difference between nitrate from artificial fertilizer and manure or animal waste as well as nitrate formed from nitrification of organic material and consequently the dominant source of the nitrate to be indicated. Once the origin of nitrate in drinking water sources is understood, corrective measures may be taken to prevent or minimize further contamination.