Of all the gases found on Earth, radon is the rarest and most expensive, although it is difficult to take a sample of soil air or groundwater in which it is not detected, even in small amounts. Radon is a gas, a product of the radioactive decay of radium, with a half-life of 3.86 days, meaning it cannot accumulate since it decays relatively quickly. This feature has earned it the status of the most dangerous among radioactive poisons.
But as often happens in life, even terrible poisons can have therapeutic effects in well-dosed amounts. This is also true for radon: when present in water at concentrations from 5 to several hundred nCi/l, it has a beneficial balneological effect for many diseases.
This gas appears in water during the movement of underground flows in rocks enriched with radium; such rocks can be granites, in which radioactive elements are dispersed during the formation of the rock, or so-called secondary collectors, where radium has gradually accumulated at a hydrochemical barrier. Radon waters of the first type are very numerous in Kyrgyzstan, but the concentration of gas in them is relatively low; they are usually cold, fresh, and have not been practically used in any of the many dozens of cases known to hydrogeologists. Only at the radon baths of Jylisu on the right bank of the Malyy Naryn River does a local balneological clinic operate, but it primarily uses these waters as hot, low-mineralized, and for hygienic purposes.
The only deposit of radon waters in Kyrgyzstan, whose formation is most likely associated with phenomena of secondary adsorption of radium, is the Jety-Oguz deposit. The composition and quantity of dissolved salts in the water of this deposit are unique and do not have sufficiently complete analogs in other countries.
Jety-Oguz is located in the southeastern part of the Issyk-Kul region on the northern slope of the Teskey Ala-Too range in the valley of the river of the same name at an altitude of just over 2200 m. The mineral waters here have a temperature of 20—42°C, a mineralization of 0.9—13 g/l, predominantly a calcium-sodium chloride composition, and a significant predominance of nitrogen among dissolved and spontaneous gases. The increased mineralization of the therapeutic waters is likely related to the discharge in the considered structure of deep circulation water from the Issyk-Kul artesian basin located to the north of the deposit.
The practical development of the Jety-Oguz mineral water deposit began in 1896 with the construction of primitive baths at thermal springs; currently, an assessment of the reserves of therapeutic waters has been conducted, but only about 1/5 is used for its direct therapeutic purpose.
However, the reasons for the radioactivity of the water are not always established convincingly. For example, several decades ago, the presence of radon in much greater quantities than 5 nCi was detected in warm springs in the valley of the Kara-Balta River; however, repeated measurements over the last 5—10 years have found this gas only in background concentrations.
