Due to very high concentration of organic matter there is a great need for alternative solutions for drinking water disinfection in the world. Chlorine dioxide has been successfully used for almost 50 years for disinfection and later for taste removal, odor control, color reduction and oxidation of inorganic compounds such as iron and manganese. An advantage of using chlorine dioxide instead of chlorine is that it does not directly react with organic matter and form halogenated byproducts when it is used for disinfection. THMs, such as CHBr3, ChCl3 etc, are considered as most dangerous for people health. In this article we are to represent the results got from raw water disinfection treatment with chlorine dioxide.

This study investigates the possibilities of using Lagenaria vulgaris biomass as a biosorbent for removal of heavy metals from wastewater and natural water. The experiments were carried out with model solutions of Pb2+, Cd2+, and Zn2+, in batch system. The effects of contact time, temperature, initial metal concentration and adsorbent doses, on the adsorption of heavy metals have been studied. Results show that biosorbent based on Lagenaria vulgaris represent efficient and low-cost means for pretreatment of heavy metals contaminated waters.

The length - weight relationship of juvenile anchovy, Engraulis encrasicolus at Bokakotorska Bay (Adriatic sea, Montenegro) was analyzed. The better knowledge of juvenile growth needs more attention for the entire Adriatic, especial for the Montenegrin coast were this investigation made for the first time. The results obtained from this investigation were compared with the data obtained from the period 1989-1991 from the area of Novigrad Sea of the the eastern Adriatic coast (5).

Samples for phytoplankton investigations were collected in annual period (September 2003 - August 2004) in the Kotor and Risan Bay. Mean-values percentage contribution of the group diatoms (Bacillariophyceae) through the annnual period were from 79.70% to 86.50%. Species Skeletonema costatum, Pseudo-mitzschia delicatissima, Leptocylindrus minimus and Chaetoceros affinis, were the main edificators of diatom population. Densities of these species were from 10**5 to 10**6 cells/cubic dm. These values are characteristic of eutrophic and extreme eutrophic area. It is needed one permanent monitoring to protect this part of Boka Kotorska Bay negative consequences.

The groundwater quality on the National Park Kopaonik is determined by the chemical and radioactive structure of water, formed through the processes that due to the contact of minerals from the water - bearing rocks and groundwater. Atmosphere precipitation are the main source of the entire resources of the ground water in the national park, and the aggressive components that are carried into the underground are the main catalyst in the process of leaching of the predominant minerals from the water-bearing rocks. In the national park, crystalline and marble limestones have the greatest water potential in the sense of the quantity and quality, and the granite massif dispose with the ground water, with the most complex radioactive structure.

Growing number of population require growing demand for water. In Sremska Mitrovica area geohydrology conditions of neogen sequence have properties of good collector for groundwater. Geological factors are such that atresian groundwater in Sremska Mitrovica area are divided in four hydrogeological zones. In all zones physical and chemical characteristics of groundwater comply with conditions for water supply.

Research of the seasonal dynamics of the zooplankton abundance was carried out during the two-year period from January 2005 to December 2006. The sampling took place in monthly intervals from five different sites from the surface to the bottom of the lake. Taking into concidertion the temperature and oxygen regime the division on the epilimnion and hipolimnion was found out. Significant numerous in the total abundance of the zooplankton accomplish taxa Daphnia sp., Bosmina sp. and Cyclops sp. Zooplankton is more abundant in the epilimnium, in the layer with more favourable temperature and oxygen regime comparing with hipolimnium. Presence of the zooplankton has been recorded in the lack of the oxygen in hipolimnium during summer months. After the elimination following the heavy rains, the hasty increase of the zooplankton numerous was recorded. Abundance of the zooplankton was higher was in shallow parts of the lake in the area of the mouth comparing the sites close the dam. This research has shown that the zooplankton was present in all parts of the lake during entire year, especially in the epilimnion that characterizes with the favourable temperature and oxygen conditions.

The results of researches of the degree of metals (Fe and Cu) of accumulation in certain species aquatic macrophytes and their organs which sampled in three lakes near city Kragujevac are exposed in this study. The results show variability of the degree of accumation of Fe and Cu among species, their organs and researched localities, and capacity of some aquatic macrophytes species and their organs which accumulate high level of mentioned metals from aquatic environment. Results obtained in this reserches pointed important role of macrophytes vegetation in bioindication and phytoremediation, and ability for use for monitoring pollutants, in studies of quality aquatic ecosystems and their protection, repairing and revitalization.

During 2005-2006 the seasonal researches were taken place aiming to investigate the influence of the urban waste water on the qualitative and quantitative structure of the community of macrozoobenthos in Gabrovacka river. For this purpose five sites were determined and the sampling of the macrozoobenthos was organized on the seasonal level using Surber net.