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.

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.

The objective of the paper is establishing of eco-chemical characterization of the river system by investigating and distribution heavy metal content in the river sediments using sequential extraction and total digestion. Heavy metals toxicity and bioavailability in the Danube river sediment are defined according to their distribution between different phases. Sediments samples were taken from 9 sites and analysed for cadmium (Cd), iron (Fe), manganese (Mn), lead (Pb), copper (Cu), zinc (Zn) and chromium (Cr), and the results about cadmium and iron presented in this paper.

In this work, the horizontal and vertical distribution of metals in the sediment of the DTD canal was studied, in a 6 km long polluted section between Vrbas and Bezdan. The assess sediment quality and the bioavailability of heavy metals, sediment samples were analyzed for total metal content, acid volutile sulphides (AVS) and simultaneously extracted metals (SEM). A high total metals content was determined (mainly Cu, Ni and Zn), which indicates that the sediment requires remediation. The AVS and SEM results show that in almost every profile, the molar concentration of metals is less than the molar concentration of sulphides, which suggests that in practice, the metals are not bioavailable. The high metals content of the sediment means that drudging of the canal will be necessary, during which, attention will have to be paid to avoid causing negative effects from the metals present in the sediment.

Aquatic biotopes are, due to their features, among the most disposed ecosystems to bioinvasion. Serbia waters are not an exception, with and increasing colonization by allochthnous organisms observed there during the last few decades. Non-indigenous aquatic species were found among plants, vertebrates and invertebrates. The aim of this work is to present the current status of aquatic ecosystems in Serbia in regard to biological invansions and to point up to the problem of introduction, presence and influence of aquatic non-indigenous species.