Radon sources and impacts: a review of mining and non-mining issues

Abstract

Radon is a ubiquitous natural carcinogen derived from the three primordial radionuclides of the uranium series ( 238 U and 235 U) and thorium series ( 232 Th). In general, it is present at very low concentrations in the outdoor or indoor environment, but a number of scenarios can give rise to significant radiological exposures. Historically, these scenarios were not recognised, and took many centuries to understand the links between the complex behaviour of radon and progeny decay and health risks such as lung cancer. However, in concert with the rapid evolution in the related sciences of nuclear physics and radiological health in the first half of the twentieth century, a more comprehensive understanding of the links between radon, its progeny and health impacts such as lung cancer has evolved. It is clear from uranium miner studies that acute occupational exposures lead to significant increases in cancer risk, but chronic or sub-chronic exposures, such as indoor residential settings, while suggestive of health risks, still entails various uncertainties. At present, prominent groups such as the BEIR or UNSCEAR committees argue that the 'linear no threshold' (LNT) model is the most appropriate model for radiation exposure management, based on their detailed review and analysis of uranium miner, residential, cellular or molecular studies. The LNT model implies that any additional or excess exposure to radon and progeny increases overall risks such as lung cancer. A variety of engineering approaches are available to address radon exposure problems. Where high radon scenarios are encountered, such as uranium mining, the most cost effective approach is well-engineered ventilation systems. For residential radon problems, various options can be assessed, including building design and passive or active ventilation systems. This paper presents a very broad but thorough review of radon sources, its behaviour (especially the importance of its radioactive decay progeny), common mining and non-mining scenarios which can give rise to significant radon and progeny exposures, followed by a review of associated health impacts, culminating in typical engineering approaches to reduce exposures and rehabilitate wastes.

Radon and Thoron Exhalation Rates from Surface Soil of Bangka - Belitung Islands, Indonesia

“…The 222 Rn and 220 Rn are free to move through soil pores and rock fractures; then to escape into the atmosphere. 222 Rn and/or 220 Rn exhaled from the earth surface into the free atmosphere is rapidly dispersed and diluted by I J O G natural convection and turbulence (Mudd, 2008;Hassan et al, 2011). 222 Rn and 220 Rn in the ambient air depend on the soil conditions and the local geological background.…”

Current State of Development of Electricity-Generating Technologies: A Literature Review

“…Alpha decay of Ra-226 produces 222-Rn ("Radon"), which as a noble gas emanates into the air adjacent to the tailings, and represents the main radiological concern not only from uranium mining operations, but in fact from the entire nuclear fuel chain [118]. When inhaled, Radon can decay into its daughter Po-218 ("Polonium"), which as an ion can attach itself to human lung tissue, and, at sufficiently high exposure, can cause elevated lung cancer risk [119]. Radon occurs naturally, and is responsible for an average radiation dose to humans of about 1-2 mSv/y, depending on location [120] (the Sievert (Sv), or milliSievert (mSv), is the unit of the so-called dose equivalent, which measures the effective biological impact from exposure, weighted by type of radiation (alpha, beta, gamma), by organ types, and other factors [119]).…”

“…Mudd [119,122] has compiled a large and detailed body of information available on radioactivity releases from operating and closed uranium mines. Whilst there is agreement that emissions and safety standards have vastly improved since the 1950s, there are conflicting conclusions about the level of safety provided by current practices, and the success or failure of current mine rehabilitation efforts [121,[123][124][125][126].…”

Radón en la mina Coricancha, San Mateo de Huánchor

“…El radón fue identificado como un problema de salud cuando los científicos se dieron cuenta que los mineros de uranio trabajando bajo tierra que estaban expuestos al radón morían por cáncer de pulmón en índices superiores a lo que se esperaba [2]. La mayor parte de lo que se conoce acerca del radón como causante potencial de cáncer proviene del estudio sobre estos mineros los cuales fueron luego confirmados por estudios con animales, que muestran índices más altos de tumores en el pulmón en los roedores expuestos a altas cantidades de radón.…”