The research results of this dissertation considered a multi-criteria approach to risk assessment  for the aquatic ecosystem and other environmental media during the activity of dredging and sedimentation, which is characterized by high concentrations of toxic heavy metals. Quantification of the risk of metal mobility was considered at several research sites in the Autonomous Province of Vojvodina (Serbia), and the obtained results were presented through three phases of research. The first phase characterized the quality and risk of undisturbed watercourses, ie the Veliki Bački and Begа canals. The distribution of organic and inorganic pollutants was examined by characterization of exploratory sediments. Detection of high concentrations of metals Ni, Zn, Cr and Cu indicated the dominant anthropogenic degradation of the exploration watercourses and the need for the necessary revitalization. The use of synthetic organic and inorganic indicators characterized the sources of origin of metals and PAHs, as well as the levels of potential environmental risks. In the second phase of the research, the potential remobilization of metals was examined, during the activities of dredging and sediment deposition at several different research locations in the area of  AP Vojvodina. The characterization of the sediment before the conducted activities indicated the quality  of I and II class, while some locations suggested contaminated sediment with Ni and Cu metals. The indicator of metal origin (Igeo) showed the dominant natural origin of Ni at all exploration sites, while it characterized certain metals such as Cu and Hg as anthropogenic. During sediment destabilization activities, the risk of metal release into surface water was not  detected. After dredging and mixing of sediment at the landfill, most of the results indicate insignificantly contaminated sediment, classified in categories I and II. Applying the algorithm for safe dredging of contaminated sediment at the Itebej na Begeju constitution, the third phase of the research characterized the potential risks during the activities of dredging and sediment disposal in the environment. The initial level of pollutants indicated high concentrations of metals Ni, Cd and Cu in the sediment, and the characterization of the surrounding coastal soil suggested high concentrations of Cu, Zn, Pb and Cd. High concentrations of metals in the sediment were considered using indicators (I geo) and environmental risk (RI). By characterizing different sediment fractions using sequential extraction (BCR), the dominant binding of detected metals to organic matter, sulfides and minerals was determined. The toxicity test on Vibrio fischeri bacteria indicated a high percentage of inhibition, however, the application of the TCLP test and considering the sediment as a waste, its disposal was characterized as safe. The initial characterization of pollutants in groundwater indicated high concentrations of Zn and As, and the quality of surface waters was characterized by class II and III, downstream-upstream in relation to the Itebej constitution. No significant metal remobilization was detected during  sediment dredging activities,while the suspended sediment indicates elevated metal concentrations Hg, Cu, As, Zn and Cr, however, the concentration of suspended matter was low, so no risk to the aquatic ecosystem was detected. After sediment deposition in  the environment and its characterization, high concentrations of Cd and Cu were detected. With the maturation of the deposited matrix in the period from 2017 to 2019, an exponential drop in concentrations is observed, which indicates a decrease in the metal content during the aging of the landfill. Applied indicators Igeo and RI characterized a reduction in overall risk during landfill maturation, while a toxicity test on Vibrio fischeri bacteria suggested mildly toxic sediments with a potential negative effect on living organisms. Consideration of different fractions in the sediment using sequential extraction (BCR) identified a decrease in the bioavailability of these metals during landfill maturation.  X-ray tenics XRF and EDS showed a growth trend of Si  during sediment maturation, which contributed to the formation of new mineral forms. X-ray diffraction analysis (XRD) enabled the identification of minerals such as quartz, muscovite, albite, illite and firopilite, which through a series of geochemical processes show a high affinity for the incorporation of Cu and Cd metals. Characterization of leachate at the landfill revealed a high risk of soluble organic pollution such as BOD 5 and HPK, total nitrogen and ammonia, while metal concentrations in leachate indicate the production of iron, manganese and copper.  Two-year monitoring of the potential impact of the landfill on groundwater quality did not detect high continuous risks of diffusion of pollutants.