Agriculture: While agricultural activities normally are carried out in the interest of human life and survival, it is one of the main and most intense polluters of our water sources. Especially in the 3 focus rivers, all three of which decrease the water quality of the Danube! Pollution originating from agricultural activities consists of nutrient pollution, raising levels of elements such as phosphate, nitrogen and carbon. These might come from substances such as animal manure, fertilizers and pesticides, yet they are discharged into a source of drinking water, often without the slightest treatment. An example of a way in which this affects a water ecosystem, is by causing eutrophication. This is the process by which a water ecosystem becomes more productive leading especially to an excessive growth of algae. This becomes hazardous for the fish and other living organisms that eventually suffocate as a result of the intense algal growth.

Another negative impact on quality of water had drainage of the land in order to intensify agricultural production. As a result, a lot of valuable wetland sites were lost. Wetlands are natural purification systems which can significantly improve the quality of water.

Municipality: Illegal dumpsites, the inappropriate location of landfills, and the insufficient treatment of waste water from households markedly contribute to water pollution. In the Morava River basin, less than 30 %, in Mura River basin about 50 % of the local people have access to a public sewerage system. As a result, a large amount of untreated household waste (anything flushed down the toilet or drained into the sing) and sewerage also make it into the Morava, Mura and later into the Danube.

Industry: Pollution originating from industrial activities consists of toxic pollution. Although this is also a significant source of pollution and very hazardous, it is not as severe a problem, in the case of these three rivers, as are the agricultural and municipal discharges.