An initial assessment of radiation doses received from radon by recreational cavers in the Mendip Hills, UK

Department of Medical Physics, Princess Margaret Hospital, Swindon, SN1 4DB, UK

Fresenius Environmental Bulletin [Fresenius Environ. Bull.]. Vol. 9, no. 11-12, pp. 766-773. Nov-Dec 2000. ISSN 1018-4619

Raised radon gas levels exist in mines and Show Caves, which are subject to regulations to reduce dose to workers and public by improving ventilation or restricting access. In the Mendip Hills, a radon Affected Area, there are a number of cave systems with unrestricted access to recreational cavers. This paper reports radon level measurements in a number of caves. In most, the levels are modest, but in one extensive cave system, the entrance section has levels over 10,000 Bq.m super(-3). Cavers would only receive a modest dose on a single visit, but many use the cave more regularly. Some would exceed the radiation dose limits for the workplace. Surveys to identify all affected caves, and action to limit dose to regular cavers in affected caves, are appropriate.