An attempt to identify and estimate the subsurface groundwater discharge in the south east coast of India

An attempt has been made to study the subsurface groundwater discharge (SGD) in the coastal Cuddalore region of south east India. Measurement for Radon, water level, Electrical Conductivity (EC) and pH in surface water for a total of twenty hours by hourly interval has been attempted and further correlated with tidal values calculated by WX Tide 32 software. The SGD measurements were made by using a modified seepage meter. The study reveals a match with water level variation and tide with minor variation due to influx of surface water. Saline discharges, fresh groundwater discharges and surface water mixing processes were identified along the coast. Lower SGD (37.24–79.16 cm/day) was observed during fresh groundwater discharge

The occurrence of 226Ra and 228Ra in groundwaters of the Polish Sudety Mountains

The paper presents preliminary measurement results of the concentrations of 226Ra and 228Ra isotopes in the groundwaters of the Polish part of the Sudety Mountains. The analysis of sampling results for water from 55 intakes showed that the average concentrations amount to 0.144 Bq/dm3 for 226Ra and 0.083 Bq/dm3 for 228Ra, while the extreme values reach 0.007 and 0.92 Bq/dm3 for 226Ra, and 0.004 and 0.4 Bq/dm3 for 228Ra. The activity ratio 228Ra/226Ra in the examined groundwaters ranges between 0.099 and 2.059. The result of the conducted research implies that the highest concentrations of 226Ra and 228Ra occur in the waters with the highest general mineralization (the highest values of total dissolved solids (TDS))

Seasonal changes of radon concentration in Niedzwiedzia cave (SW Poland)

The paper presents the results of measurements of average monthly radon concentrations obtained in the most beautiful Polish cave, the Niedz´wiedzia Cave, between July 1995 and December 1996. 222 measurements were taken at 7 measurement points with the use of trace detectors LR-115 type II. Distinct seasonal fluctuation of the concentration was observed: the highest values (up to 3.60 kBq/m3) were noted in summer (from April to September), while the lowest ones in winter (0.10 kBq/m3, in January 1996). A sharp increase in the concentration in spring and a decrease in autumn are typical. The main factor controlling radon concentration changes in the air of the Niedz´wiedzia Cave is the process of ventilation

Natural radioactivity of groundwater from the Przerzeczyn-Zdrój Spa

The present authors performed investigations of natural radioactivity in groundwater from the Przerzeczyn- -Zdrój Spa. Some of the waters are regarded as medical and are used for balneological purposes. Samples from seven groundwater intakes were collected 5 times over a period of 8 years (1999–2007). In order to obtain necessary data, two different nuclear spectrometry techniques were applied: α spectrometry and liquid scintillation spectrometry. The activity concentrations of 222Rn varied in the range from 15±2 Bq/l to 154±22 Bq/l. The results of activity concentrations of 226,228Ra varied from below 10 mBq/l to 30±1.5 mBq/l and from below 30 mBq/l to 60±4 mBq/l, respectively. Activity concentration lower than minimum detectable activity (MDA) was obtained for 3 samples for 226Ra and 4 for 228Ra determinations out of 7 investigated samples. The uranium content in the studied samples was determined once and the value ranged from 4.5±0.6 mBq/l to 13.6±1.2 mBq/l for 238U and from 17.1±0.9 mBq/l to 52.2±2.8 mBq/l for 234U. All obtained values for uranium isotopes showed activity concentrations above MDA. The activity ratios 234U/238U, 222Rn/226Ra and 226Ra/238U and the correlations between different isotopes concentrations were evaluated

The presence and dosimetry of radon and thoron in a historical, underground metalliferous mine

A combination of long term passive, and short term active radon-222, radon-220 and respective progeny measurements were conducted in both traverse and longitudinal axes of a historical metalliferous underground mine in North Queensland, Australia. While the passive monitor results provided average radon and thoron air concentrations over periods of 70–90 days, active measurements over a four day period provided significantly more detail into the dynamics of radon and progeny concentrations in the naturally ventilated mine environment. Passive monitor concentrations for radon and thoron ranged between 60 and 390 Bq m−3 (mean: 140 ± 55 Bq m−3) and 140 and 2600 Bq m−3 (mean: 1070 ± 510 Bq m−3) respectively, with passive thoron progeny monitors providing a mean concentration of 9 ± 5 Bq m−3EEC. Active measurement mean concentrations for radon, thoron, radon progeny and thoron progeny in the centre of the mine drive were 130 ± 90 Bq m−3, 300 ± 100 Bq m−3, 20 ± 20 Bq m−3EEC and 10 ± 10 Bq m−3EEC respectively.It was identified that thoron passive detector placement is critical in establishing reliable monitoring data, and is the reason for the discrepancy between the active and passive thoron results in this study. Site specific progeny measurements are required for the accurate estimation of dose to persons entering the mine. Based on short term active measurements and passive thoron progeny monitor results, the dose contribution from thoron and progeny in the mine was observed to contribute up to 80% of the total radon/thoron inhalation dose, and therefore should not be underestimated in monitoring programs under similar conditions

Short-term <sup>222</sup>Rn activity concentration changes in underground spaces with limited air exchange with the atmosphere

Abstract. The authors investigated short-time changes in 222Rn activity concentration occurring yearly in two underground tourist facilities with limited air exchange with the atmosphere. One of them is Niedźwiedzia (Bear) Cave in Kletno, Poland – a natural space equipped with locks ensuring isolation from the atmosphere. The other site is Fluorite Adit in Kletno, a section of a disused uranium mine. This adit is equipped with a mechanical ventilation system, operated periodically outside the opening times (at night). Both sites are situated within the same metamorphic rock complex, at similar altitudes, about 2 km apart. The measurements conducted revealed spring and autumn occurrence of convective air movements. In Bear Cave, this process causes a reduction in 222Rn activity concentration in the daytime, i.e. when tourists, guides and other staff are present in the cave. From the point of view of radiation protection, this is the best situation. For the rest of the year, daily concentrations of 222Rn activity in the cave are very stable. In Fluorite Adit, on the other hand, significant variations in daily 222Rn activity concentrations are recorded almost all year round. These changes are determined by the periods of activity and inactivity of mechanical ventilation. Unfortunately this is inactive in the daytime, which results in the highest values of 222Rn activity concentration at the times when tourists and staff are present in the adit. Slightly lower concentrations of radon in Fluorite Adit are recorded in the winter season, when convective air movements carry a substantial amount of radon out into the atmosphere. The incorrect usage of mechanical ventilation in Fluorite Adit results in the most unfavourable conditions in terms of radiation protection. The staff working in that facility are exposed practically throughout the year to the highest 222Rn activity concentrations, both at work (in the adit) and at home (outside their working hours). Therefore, not very well considered solution for the ventilation system not only does not prevent radioactive exposure of the staff, but can even increase it. The authors have also observed comparable characteristics of the annual patterns of 222Rn activity concentration changes in underground spaces and residential buildings situated in the same or similar climatic zones. </jats:p

National comparison of methods for determination of radon in water

The article describes three interlaboratory experiments concerning 222Rn determination in water samples. The fi rst two experiments were carried out with the use of artifi cial radon waters prepared by the Laboratory of Radiometric Expertise (LER), Institute of Nuclear Physics, Polish Academy of Sciences in Kraków in 2014 and 2018. The third experiment was performed using natural environment waters collected in the vicinity of the former uranium mine in Kowary in 2016. Most of the institutions performing radon in water measurements in Poland were gathered in the Polish Radon Centre Network, and they participated in the experiments. The goal of these exercises was to evaluate different measurement techniques used routinely in Polish laboratories and the laboratories’ profi ciency of radon in water measurements. In the experiment performed in 2018, the reference values of 222Rn concentration in water were calculated based on the method developed at LER. The participants’ results appeared to be worse for low radon concentration than for high radon concentrations. The conclusions drawn on that base indicated the weaknesses of the used methods and probably the sampling. The interlaboratory experiments, in term, can help to improve the participants’ skills and reliability of their results

Radon intercomparison tests – Katowice, 2016

At the beginning of the year 2016, the representatives of the Polish Radon Centre decided to organize profi ciency tests (PTs) for measurements of radon gas and radon decay products in the air, involving radon monitors and laboratory passive techniques. The Silesian Centre for Environmental Radioactivity of the Central Mining Institute (GIG), Katowice, became responsible for the organization of the PT exercises. The main reason to choose that location was the radon chamber in GIG with a volume of 17 m3, the biggest one in Poland. Accordingly, 13 participants from Poland plus one participant from Germany expressed their interest. The participants were invited to inform the organizers about what types of monitors and methods they would like to check during the tests. On this basis, the GIG team prepared the proposal for the schedule of exercises, such as the required level(s) of radon concentrations, the number and periods of tests, proposed potential alpha energy concentration (PAEC) levels and also the overall period of PT. The PT activity was performed between 6th and 17th June 2016. After assessment of the results, the agreement between radon monitors and other measurement methods was confi rmed. In the case of PAEC monitors and methods of measurements, the results of PT exercises were consistent and confi rmed the accuracy of the calibration procedures used by the participants. The results of the PAEC PTs will be published elsewhere; in this paper, only the results of radon intercomparison are described