To characterize the future redox milieu caused by natural degradation of wood in flooded mines, the aquifer of a highland
bog ground was studied as a natural analogue site. Going from the surface to a depth of one meter in the bog water, the redox
potential measured with a platinum electrode changes from 593 mV to −95 mV. From the depth-water analyses and analyses of
bog gas extracted from the ground, an Eh value of −119±5 mV could be calculated. Methane and hydrogen sulfide were found in
the gas, characterizing the strongly reducing condition in the bog ground. From that, the conclusion for the future mine situation
can be drawn that uranium(VI) and arsenic(V) will be reduced and precipitated as U(OH)4 and As2S3. In that way, decontamination of the mine water takes place as a consequence of a natural attenuation process.
Authors:Tadeusz Przylibski, Jakub Bartak, Elżbieta Kochowska, Lidia Fijałkowska-Lichwa, Krzysztof Kozak, and Jadwiga Mazur
The article presents new Polish probes SRDN-3, developed at the Institute of Nuclear Chemistry and Technology in Warsaw, equipped
with a semi-conductor detector used for continuous measurements of 222Rn activity concentration. Due to a relatively high lower detection limit, the device is dedicated for use in underground
spaces—caves, adits, mines, tourist routes in strongholds, pyramids, etc. Its structure allows for difficult conditions in
which the device is transported to the measurement site, as well as hard operating conditions caused chiefly by large ambient
relative humidity, reaching up to 100%. The authors present calibration results of these appliances, as well as the results
of their work in a cave and an adit in the Sudetes (SW Poland). After almost 2 years of working in difficult conditions, the
probes displayed high reliability. No defects of the semi-conductor detectors or the electronics were observed, which ensured
problem-free communication of the probe-programmer-PC set. Thanks to this, the authors have a 2 year stock of data, recorded
hourly by five probes, at their disposal. The only element that did not withstand the test of extreme operating conditions
was one of the combined relative humidity and temperature sensors. No powering problems were observed either, and the batteries
were replaced once a year, before the winter season. Also the programmer functioned faultlessly, enabling data transmission
to a PC, which, being much more sensitive to operating conditions, had been placed away from the site of probe exposure. After
using more sensitive temperature, relative humidity and pressure sensors, SRDN-3 probes will certainly prove an excellent
tool for microclimate measurements (including measurement of air-atmosphere exchange) in caves and other underground sites.
Even nowadays they are already a satisfactory tool for monitoring 222Rn concentration in underground spaces.
This work describes a method which was developed to determine the concentration of 222Rn gas and the equilibrium factor F between the concentration of the gas and its progeny by means of a single device that uses two Makrofol passive track detectors. The device is completely passive and time integrated. Conditions make it very appropriate to be used in any atmospheres in which human activity takes place, such as houses, schools, works and underground mines. A series of measurements of 222Rn gas concentration and equilibrium factor F were made in different cities of the Argentine Republic and the corresponding levels of doses were estimated.