Lake Elton

Lake Elton (Russian: Эльтон; Kazakh: Эльтон, romanized: Elton) is a salt lake in Volgograd Oblast, Russia, near the border with Kazakhstan. It has an area of 152 kilometres (94 mi) and is normally about 0.1 metres (4 in) deep, and about 0.7 to 0.8 metres (28 to 31 in) in spring. Its surface is 18 metres (60 ft) below sea level. The lake's name originates from the Mongol language: “Altyn-Nor” (Golden Bottom). Long ago local nomads used the lake's mineral-rich mud for skin and respiratory treatments. For centuries, Lake Elton was a favorite location for Russian rulers and nobles. One can still see remnants of Empress Yekaterina II's “bath” there.

It is the largest mineral lake in Europe and one of the most mineralized in the world. The lake is filled with a saturated salt solution. Mineralization is 200–500 grams per litre (27–67 oz/US gal). Salt, extracted from the lake since the early 18th century, is used for the production of magnesium chloride. The water contains Dunaliella salina algae that give a reddish shade to the lake. At the bottom of the lake are salt deposits (mainly NaCl, KCl) and beneath them, a layer of mineral hydrogen sulfide mud.