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Radon decay products in the boundary layer of the atmosphere

Otahal P., Burian I.

Nukleonika

2010

Vol. 55, No. 4

539-542

The concentration of radon and its decay products in the boundary layer of the atmosphere varies and depends on many factors. One of the main factors leading to the variability of equilibrium equivalent concentration (EEC) of radon is the dynamic behavior of the atmosphere. Describing the behavior of radon concentration and EEC in the atmosphere is important for the estimation of natural human exposition (this was our original goal). The National Institute for Nuclear, Chemical and Biological Protection (SÚJCHBO, v.v.i.) has been investigating the characteristics of radon decay products in the boundary layer of the atmosphere since 1985. The measurements of EEC were carried out in places with different exhalation of radon from the subsoil. The grab sampling method, as well as continuous measurement, were applied in various areas. The determination of outdoor radon and radon daughter product (RnDP) is not easy due to very low levels of their concentrations: therefore, many methods and devices had to be modified for this type of measurement.

Environmental and radon measurements in the underground workplaces in the Czech Republic

Thinova L., Rovenska K., Otahal P.

Nukleonika

2010

Vol. 55, No. 4

491-493

Most of radon and other environmental measurements were carried out in connection with research focused on improvement of radon dose assessment in the underground workplaces in the Czech Republic. The following methods are very useful for the detection of radon sources: air flow measurement; continual and short volume activity of radon and its progeny measurement; volume activity of thoron measurement; mapping of radon level in all workplace areas including horizontal and vertical gradient; radon in water measurement; integral radon monitor RAMARN testing, etc. In conjunction with equilibrium radon concentration (ERC) monitoring studies were conducted of radiogenic characteristics of caves clastogene and carbonate sediments, and other rock formations present in the Czech Massif and Western Carpathian. Over 150 samples of cave sediments were collected, in which the mass activities of present radionuclides were determined. Spectrometric analysis of the sediments enabled monitoring of disturbance in secular radioactive equilibrium in the given geochemical systems, through evaluation of 238U/226Ra or 228Th/224Ra proportion. Ratio of 208Tl/226Ra was monitored for the rock groups from the origin point of view assessment. Typical values for such ratio for carbonate rocks (including amphibolite and erlan) varied between 0.2–0.5, while for clastogene sediments and crystalline limestone the typical values were in the range 1.4–1.6. Conclusions from measurements were implemented in the new methodology for radon dose assessment.