Spatial and temporal variations of radon and radon daughter concentrations within limestone caves

Abstract

This thesis outlines results from an investigation of radon and radon daughter concentrations in limestone caves, from a geographical and geological perspective Investigations were conducted at all geographical scales, ranging from a national investigation in the four major caving regions of England and Wales to a detailed survey within a single cave in the Peak District. The measured radon concentrations in some limestone caves in England and Wales are amongst the highest ever recorded in the world Significant spatial and temporal variations were recorded m concentrations at all scales, within a single cave, between caves in the same region and between different regions Additionally, seasonal and diurnal variations in concentrations were highlighted. External climatic variables and the cave radon budget were demonstrated to account for variations in cave radon concentrations Within limestone caves seven primary sources of radon were identified and the relative importance of each to the overall radon budget was determined Sediments and the contaming limestone rock were the major sources although in certain cases water and the soil were demonstrated to be influential Models were developed to predict cave radon concentrations within a single cave However, these could not be transposed to predict radon concentrations in other caves in the same region or other regions The users of limestone caves were identified, their potential exposure times were examined and legislation concerning their exposure was discussed Four groups were identified as being at risk from radon while underground, and three groups were identified as bemg at little risk Methods by which the risk from radon exposure can be reduced were examine