Eutrophication sources. Eutrophication can be defined as enrichment of waters by inorganic plant nutrients, particularly nitrogen and phosphorous. This phenomenon can be either artificial (or cultural) or natural, depending on anthropogenic or natural causes.Sources of artificial pollution are either urban or rural.Urban sources of eutrophication include domestic sewage, industrial wastes and storm drainage. The contribution of nitrogen and phosphorous per person is 10.8 g N and 2.2 g P on average [3] .ources of artificial pollution are either urban or rural. Urban sources of eutrophication include domestic sewage, industrial wastes and storm drainage. The contribution of nitrogen and phosphorous per person is 10.8 g N and 2.2 g P on average [3] .