In previous works numerous specific changes of water composition in the Danube backwater effects Iron Gate 1 reservoir (Yugoslavia), have been initiated. By studies of conditions of generation and composition of sediments, the models denying importance of assumption on sedimentological features of deposited materials foreseen by the project, have been established, as it was confirmed with more details by newer investigations. The new data on the character of sediments coincide in all elements with changes of water composition, which was formerly presented, thus the knowledges of these phenomena being in that way more important. The data on composition of the deposited material, the macro and micro-composition are of great importance to perceive the influence of new sediments to the quality of surface and groundwater, especially of the sources for water supply, then in a long term for the sudden high risk processes corresponding to a chemical time bomb. Data have confirmed validity of the model of intensified deposition of allochthonous material with plankton and influence of this phenomenon to the processes trough the downstream section.

Nowadays, different profile of experts are present opinion that surface water quality are exchanged. Type and degree of mineralization content exchange are shown by argumentation. The work have carried out taking into consideration suitability of Danube water for irrigation. The results of chemical investigation from three sample locations (Bezdan, Novi Sad and Banatska Palanka), Serbia (Yugoslavia) during the period 1981-1995, were analyzed. The main statistical parameters and tests of homogeneity are used during the work. Results have pointed put more or less concentration decreasing of analyzed parameters. From statistical point of view, exchange of electrical conductivity and potassium are prominent on all three localities.