Dose estimation and radon action level problems due to nanosize radon progeny aerosols in underground manganese ore mine

a b s t r a c t One of the essential parameters influencing of the dose conversion factor is the ratio of unattached shortlived radon progeny. This may differ from the value identified for indoor conditions when considering special workplaces such as mines. Inevitably, application of the dose conversion factors used in surface workplaces considerably reduces the reliability of dose estimation in the case of mines. This paper surveyed the concentration of radon and its short-lived radon progeny and identified the unattached fraction of short-lived radon progeny. As well equilibrium factor during the month of August was calculated simultaneously at two extraction faces in a manganese ore mine. During working hours the average radon concentrations were 220 Bq m À3 and 530 Bq m À3 at Faces 1 and 2; the average short-lived progeny concentration was 90 Bq m À3 and 190 Bq m À3 , the average equilibrium factors were 0.46 and 0.36, and the average unattached fractions were 0.21 and 0.17, respectively. The calculated dose conversion factor was between 9 and 27 mSv WLM À1 , but higher values could also be possible

Natural Radioactivity in Drinking Water in the Surroundings of a Metamorphic Outcrop in Hungary: The Hydrogeological Answer to Practical Problems

Groundwater quality constantly evolves through rock–water interactions, which can enrich groundwater with undesirable elements such as naturally occurring radionuclides. The aim of this study was to understand the cause of gross alpha activity exceeding the screening value of 0.1 Bq L−1 measured in groundwater-derived drinking water in the vicinity of a metamorphic outcrop in Hungary. As groundwater quality is strongly dependent on the properties of groundwater flow systems, environmental tracers (δ2H and δ18O composition, 226Ra, 222Rn, total U activity concentration, and 234U/238U ratio) and hydraulic evaluation were applied to understand groundwater dynamics. The collected groundwater samples had total U activities up to 540 mBq L−1, which translates into an indicative dose below the drinking water parametric value. However, in the presence of dissolved uranium, the δ2H (−52.6–(−83.4)) and δ18O (−7.17–(−11.96)) values led to the conclusion that local flow systems were sampled that are known to be most vulnerable to any changes in their recharge area. The results confirm that the groundwater flow system approach involving environmental tracers and hydraulic evaluation is a powerful tool for identifying the cause of natural radioactivity in groundwater-derived drinking water

Asymmetric Warfare : Conflict of the Past, the Present, and the Future : Conference Conclusions

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