The major problems are the poisoning of birds (swans, geese and ducks) through agricultural pesticides, siltation, electro fishing by the local fishermen to harvest the fish and poverty, especially of the farmers. More than 1,000 sq. km of wetland areas were drained from 1954 to 1984. Erosion and degradation left large areas (670 sq. km) of "waste land" behind, sandy areas with no vegetation.
There exist practically no purification treatment plants for the local sewage water and therefore the eutrophication of the water increases. Nevertheless the water quality is still good (Class II). Negative impacts originate of toxic heavy metals pollution from copper mines in the eastern part of the lake.