Lithological and seasonal variations in radon concentrations in Cypriot groundwaters

Impact of meteorological parameters on soil radon at Kolkata, India: investigation using machine learning techniques

The daily soil radon activity has been measured continuously over a year with BARASOL BMC2 probe at a measuring site of Jadavpur University Campus in Kolkata, India. The dependency of soil radon activity with different atmospheric parameters such as soil temperature, soil pressure, humidity, air temperature, and rainfall has been also analyzed. The whole study period is divided in four seasons as proposed by the Indian Meteorological Department (IMD). Minimum soil radon level has been observed during the winter season (December-February). On the other hand, higher soil radon level has been observed both for summer and monsoon. Except soil pressure, all other variables have shown positive correlation with soil radon activity. Among five variables, soil temperature has been the most significant variable in terms of correlation with soil radon level whereas maximum humidity has been the least significant correlated variable. It has been observed that considerable reduction of soil radon level occurred after four heavy rainfall events during the study period. The combined effect of these multi-parameters on soil radon gas has been evaluated using machine learning methods like principal component regression (PCR), support vector regression (SVR), random forest regression (RF), and gradient boosting machine (GBM). In terms of performances, RF and GBM have performed much better than SVR and PCR. More robust and consistent results have been obtained for GBM during both training and testing periods.

Measurement of (222)Rn concentration in drinking water in Sakarya, Turkey

In this paper, the first measurement of (222)Rn concentrations in drinking water from wells, springs and bottled waters in the city of Sakarya, Turkey was presented. The measurements were performed using RAD 7, a solid-state alpha detector, with RAD H2O (radon in water) accessory manufactured by Durridge Company, Inc. The measured activity concentrations ranged from 1.98 to 20.80 Bq l(-1) with an average value of 9.05 Bq l(-1) for well water, from 0.75 to 59.65 Bq l(-1) with an average value of 13.78 Bq l(-1) for spring water and from 0.75 to 22.8 Bq l(-1) with an average value of 5.41 Bq l(-1) for bottled water. Although these results indicated relatively high (222)Rn concentrations compared with that from other parts of the Turkey, they are still below the World Health Organization recommended level of 100 Bq l(-1) for radon. Using the measured activities of (222)Rn, the age-dependent associated committed effective doses due to the ingestion of (222)Rn as a consequence of direct consumption of drinking water were calculated. The committed effective doses from (222)Rn were estimated to range from 2.59 to 205.97 µSv y(-1), from 1.55 to 123.28 µSv y(-1) and from 1.31 to 104.48 µSv y(-1) for age groups 1-2, 8-12 and >17 y, respectively.