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.

Phytoplankton composition of the Hydrosystem Danube-Tisza-Danube (HS DTD) and isolated peaks of chlorophyll a in summer months of 2003 and 2004 revealed moderate ecological potential in Banat and Backa region (Serbia). Investigated HS DTD water pointed out to a slighty better ecological potential in 2004.

During 2005 the referent monitoring of the chemical quality of surface waters and sediments in Vojvodina was conducted as a supplement to the regular monitoring program in Vojvodina. It is concluded that the water quality mainly satisfies the criteria of the 1st/2nd class acccording to our legislation, but regarding the more stringent Canadian and Dutch water quality standards content of some micropollutants may be considered as potentially problematic. Sediment quality is mainly satisfying, with the exceptions of the DTD canal Vrbas-Bezdan monitoring station after Srbobran, which showed a slight contamination with PAHs, and the Sava-Sabac monitoring station, as the target values according to Dutch legislation were exceeded for DDT and its metabolites.

There are some water reservoirs on the territory of Zajecar district area (Serbia). Their purpose and time of building are very different. It is also different the organic matter production in those reservoirs. Water reservoirs for supplying with drinking water are very specific because the increased of organic products makes some difficulties in process of refinement reservoir water to drinking water. In this paper we are trying to explain, taking the reservoir Grliste for the example, if the biomanipulation exerts on water quality in the reservoirs.

During spring of 2005, referent monitoring of the chemical quality of surface waters and sediments in some protected areas in Vojvodina (Serbia) was conducted as a supplement to the Regular monitoring program. The aim of the study was to establish the chemical quality of surface waters and sediments regarding nutrient content. It is shown that the water quality satisfies the criteria of the 1st/2nd class according to our legislation, with the exception of the Ludos location, which showed a contamination with nitrogen matter in water and sediments. With regard to the contamination of water with phosphorus, almost all locations may be considered as potentially problematic.

In the course of implementation of project Ecological Significance Evaluation of River Moravica Basin with Pollutants Identification, supported by REC and DRP, chemical and physical water analysis were done, as well as slime analysis. Heavy metals presence in water, herb Mentha aquatica and slime was analysed at six relevant locations downstream river Moravica. Heavy metals test results in slime and herb Mentha aquatica points out the presence of Zn, Cu, Fe, Mn, with heavy metals concentration rise from spring to mouth of river Moravica to river Juzna Morava. Chemical and physical analysis of water content, and detection of heavy metals presence in herb Mentha aquatica - as bioindicator and in slime, shows on water contamination with heavy metals as the inflow result of waste waters from numerous polluters.

The objective of this paper is establishing eco-chemical characterization of the Skadar lake (i.e. Lake Scutari) system by investigation of heavy metal content and distribution in the lake sediments. Factors that influence heavy metal concentrations in sediments are allochthonous (natural and human effects) and autochthonous (natural processes of settling and sorption) as well as transformation of settled substances in sediments. Sediments samples were taken from 15 sites and analysed for copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb).

In the frame of the project Water Supplying of the Cities and Protection of the Groundwater Quality in the Velika Morava Valley, was obtained the analysis of potential polluters of groundwater sources of town Velika Plana - Livade. This paper presents results of water physical, chemical and microbiological characteristics of soil. According to the results of research and way of usage of the soil, it was concluded that agricultural production does not have negative influence on quality of the groundwater source.

Investigation of the nutrients and chlorophyll a concentrations, as indicators of trophic level, in the period from September 2003 to August 2004 in three sampling locations in the inner part of Boka Kotorska Bay varied widely. Nitrate concentration ranged from 0.0 to 2.42 mg/l at the surface and from 0.02 to 3.88 mg/l at the bottom, nitrate concentration from 0.02 to 0.21 mg/l at the surface and from 0.01 to 0.6 mg/l at the bottom, phosphate concentration from 0.03 to 0.18 mg/l at the surface and from 0.01 to 0.22 mg/l at the bottom, silicate concentration from 0.0 to 1.42 mg/l at the surface and 0.45 mg/l at the bottom respectively. Value of phytoplankton biomass, as represented by chlorophyll a, ranged from 1.02 to 8.68 mg/cubic meter and from 0.49 to 5.23 mg/cubic meter at the bottom. According to the UNEP criteria during the investigated period it can be concluded that the area in question is mesotrophic with the exception of December when it is eutrophic.

During the study we recorded narrow margins between zooplankton distribution and the ecological characteristics of water in Bokakotorska Bay (Adriatic sea, Montenegro). Various species show different vulnerability to environment quality. Some are defined as indicators, with low tolerance for the ecological variation of environment, and their distribution is limited to the particular type of water masses within the sea. The limiting factors are different for various species, and their indicator status is determined by their distribution. The indicator type, based on monitoring of particular species, may define a biotope, with the help of statistical analyses that identify the main time and spacial behavior patterns of a species, and my allow future ecosystem changes to be anticipated. In this paper we paid particular attention to the indicator species Oithona nana (Giesbrecht).