Natalia Vinograd, an Associate Professor from the Department of Hydrogeology of St Petersburg University, and Dr Adam Porowski, a hydrogeologist researcher from the Institute of Geological Sciences of the Polish Academy of Sciences, have studied the chemical and isotopic composition of mineral spring water in Staraya Russa. The study has yielded new information about the origin of the water in the ancient resort springs.

The results of the scientists' work have been published in the journal Environmental Earth Sciences.

Staraya Russa is a town in the Novgorod region that appeared in the 9th century. For hundreds of years there had been a salt mining town. Then in the 18th century, people discovered the special properties of the water in the springs and lakes of Staraya Russa. Scientists began their research and in 1828 the town opened one of the oldest balneological resorts in Russia. For more than 180 years the resort has been famous for its various therapies using mud and mineral waters.

The health resort’s waters belong to a class that can be described as 'containing no specific components and properties', Staraya Russa-type water, group I-10 (the healing properties are determined by the ionic saline composition). Natalia Vinograd and Adam Porowski studied the compositions of ten springs of Staraya Russa: eight in the spa area and two more in the town. Water in the springs comes from two aquifers: the saline waters of the Middle and Upper Devonian Arukjula–Shventoy aquifer and the saline waters of Upper Devonian Sargayev–Daugava aquifer. The waters of the former are used in the spa for baths, and the latter for drinking.

The study lasted for several years, during which scientists analysed both existing materials and took new measurements. For example, they studied the isotopic composition of the spring waters of Staraya Russa for the first time, shedding light on their source.

The studies revealed that the brackish waters of the Sargayev–Daugava aquifer complex are mixtures of snow melt (precipitation water) and saline waters which ascend from the deeper Arukjula–Shventoy aquifer. The suphur (δ34S) and oxygen (δ18O) isotopic composition indicated that their source is connected to marine sulphates. The ionic ratios of the major chemical compounds confirmed the presence of a natural component similar to that of sea water in the hydrogeological system. According to the scientists, this explains the chemical composition of mineral waters in Staraya Russa.

It was established that the Middle and Upper Devonian Arukjula–Shventoy aquifer contains approximately equal amounts of ancient buried sea water and snow melt water of, presumably, the ice ages.

Natalia Vinograd, Associate Professor of the Department of Hydrogeology at St Petersburg University

'The Upper Devonian Sargayev–Daugava aquifer contains about 20-40% of the waters of the Arukjula–Shventoy aquifer (depending on the depth), the rest being snow melt waters. This corresponds to the hydrochemical data and explains the origin of the resort’s curative waters,' said Natalia Vinograd.