Published on 28 June 2016
The concentration of radon increased in comparison with the open atmosphere – well-known feature of karst caves. Alpha radiation levels in caves usually exceed atmospheric values by 10-300 times. Distribution of concentration of radon in caves is most controlled by air exchange with the external atmosphere. According to world practice, radon is one of the best natural tracers of air streams in difficult cave systems and is used for allocation of zones on intensity of air exchange. In the article, results of measurements volume activity (VA) and equivalent equilibrium volume of activity (EEVA) of radon in the New Athos cave (Abkhazia, Western Caucasus) are given. Researches conducted in September-October, 2015. VA values in a cave made from 155 Bq/m3 to 3456 Bq/m3; and EEVA values – from 98 Bq/m3 to 2519 Bq/m3. It is established that the major factor influencing concentration of radon in cave cavities is intensity of air exchange with a surface. The analysis of spatial distribution has allowed to allocate three zones which differ under the terms of air exchange: a) well ventilated southern halls (Anakopiya, Mahajirs, Nartaa, Coralloid Gallery) with most VA low values (450-1200 Bq/ m3); b) intermediate cavities between Coralloid Gallery and Apsny’s Hall (including halls of Speleologists and Givi Smyr) with VA of 1500-1700 Bq/m3); c) Apsny Hall with the complicated exchange of air and most the VA high values from 1800 to 3400 Bq/ m3. The transforming influence of the water taking away tunnel on the natural mode of air circulation is shown. The observations made with the opened and closed shutter of a wind-shelter lock in this tunnel have shown that now the lock practically doesn’t obstruct the traffic of air from a cave. Estimated calculation of effective doses of radiation of the personnel working in a cave has been carried out. The dose received by the guide for one excursion makes about 0,012 μSv, and the threshold dose established by the legislation 5 μSv in a year and this dose can be received at the loading exceeding 3-4 excursions a day.
Categories: Articles, Geo-ecological,-Recreational-and-Biomedical-Issues-of-SDMT
Tags: Новоафонская пещера, карст, микроклимат, родон, дозы облучения персонала
ISSN 1998-4502 (Print) ISSN 2499-975Х (Online)