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The Healing Mud of Lake Varna
Beneath the waters of Lake Varna lies a thick layer of black, greasy silt that smells of hydrogen sulphide. This is healing mud, which has been studied for decades and used in spa treatments along the Black Sea coast. One of the known mud deposits is in the lake near Kazashko.
What healing mud is
Scientists call healing mud a peloid. It is a complex mix of organic and inorganic substances: a liquid part (water with dissolved salts), a solid “skeleton” of crystals (calcium and magnesium carbonates, sulphates and phosphates) and a colloidal part that gives it its greasy, plastic texture.
The mud of Lake Varna is liman mud, meaning it formed in a coastal lake connected to the sea.
How it forms on the lake bed
Lake Varna is up to 19 m deep. After the canals to the sea were dug in 1909, and especially after they were widened in 1976, more and more salty sea water entered the lake. In summer, hydrogen sulphide appears in the deep layers of the lake and disappears when winter comes. This is what allows the thick layer of hydrogen sulphide silt on the lake bed to form, which is used for mud treatments.
What Varna mud is like
According to research by Dr Eng. Liliya Vladeva, the mud is grey-black to black, greasy, fine to the touch and smells of hydrogen sulphide. The water in it is of the sodium chloride type, and its mineral content is barely affected by fresh water entering the lake. In the author’s classification, the mud is low in minerals (up to 15 g/kg) and moderately sulphidic, with a composition close to that of sea water. It is extracted from great depth.
Popular publications describe it as creamy, sticky and plastic, with an alkaline reaction. Before use, the mud is sieved and warmed.
How long it has been studied
The healing mud of the lake has been studied since 1954. After 1978 the research became annual, covering more than 50 samples, and it is used to check the quality of the mud at the treatment centres that use it. Researchers have also noted traces of pollution from industry around the port in some parts of the lake.
The mud deposit near Kazashko
According to a 2017 report in the newspaper Trud, there is a rich mud deposit in the lake near Kazashko. It supplies healing mud to the specialised rehabilitation hospital in the Golden Sands resort. Mud from Lake Varna is also used in spa hotels in Varna and Albena.
The deposit lies underwater; it is not a beach for mud baths. The Kazashko Protected Site is nearby, and dredging the water area or damaging life on the lake bed is banned there.
If you remember stories of how people from the village dug or used the mud from the lake, please write to us. Memories like these cannot be found online, and they are part of Kazashko’s history.
Frequently asked questions
Is there healing mud near Kazashko?
Yes. According to Trud (2017), there is a rich mud deposit in the lake near the village, which supplies mud to the rehabilitation hospital in Golden Sands.
What is Lake Varna mud like?
It is liman, hydrogen sulphide mud: grey-black to black, greasy and fine, low in minerals (up to 15 g/kg) and moderately sulphidic.
Published: 1 October 2026