Most significant cause of Black Sea degradation is increased Eutrophication.
Eutrophication is caused primarily by increased nutrient loads (nitrogen and phosphorous) from agricultural, industrial and municipal sources along the coast and tributary rivers, especially the Danube.
58% of total nitrogen and 66% of total phosphorous flowing into Black Sea comes from the Danube River basin.
More than half of all nutrient loads into the Danube originate from agriculture.