Indoor Radon (222rn) Measurements and Estimation of Annual Effective Dose in Mvangan Locality, South Cameroon

Abstract

The present work was aimed at measuring indoor radon activity concentrations in dwellings in Mvangan locality, South Cameroon, in order to assess the extent of measures that may be necessary for controlling public indoor radon exposure in this area. Measurements were carried out using passive solid-state nuclear track detectors (RADONAVA Inc., RadTrak2, Sweden) following ISO 11665-4 standard. Radon concentration ranged between 36 ± 20 and 150 ± 30 Bq m−3 with arithmetic and geometric means values of 64 ± 25 and 60 ± 1 Bq m−3, respectively. These mean values were greater than worldwide values presented by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), which are, respectively, 40 and 30 Bq m−3. 96% of dwellings that have radon concentrations below the World Health Organization (WHO) reference level of 100 Bq m−3, whereas 4% of dwellings have radon concentrations higher than this level but lower than 300 Bq m−3, the International Commission on Radiological Protection (ICRP) reference level. Annual effective doses due to indoor radon ranged between 0.7 and 2.8 mSv y−1 with an arithmetic mean value of 1.2 ± 0.5 mSv y−1. These values were below the lower limit of the ICRP-recommended action level interval 3–10 mSv y−1. It has been observed that annual effective dose received by residents in cement bricks dwellings were not significantly different (P-value = 0.565) than those received by residents in mud dwellings in Mvangan locality. The mean number of persons expected to be diagnosed with or die from cancer (solid cancers and leukemia) were 162 ± 48 (61 ± 25 for males and 101 ± 41 for females) and 82 ± 24 (33 ± 13 for males and 49 ± 20 for females), respectively. The results obtained in this study prove that the populations of Mvangan locality are exposed to a relatively low potential risk of cancer incidence and mortality.

Preliminary Survey of Exposure to Indoor Radon in al-Farabi Kazakh National University, Kazakhstan

“…A WHO survey in 36 countries found that almost all countries set reference levels for acceptable radon concentrations for existing housing between 200 Bq/m 3 and 400 Bq/m 3 . Some countries have developed different reference levels for new and existing buildings, with lower values set for new homes [13]. A national reference level of 100 Bq/m 3 is recommended to limit the individual risk.…”

Establishment of Typical Dose Reference Level (DRL) Values for Adult Patients Undergoing Computed Tomography in Three Hospitals in Brazzaville, Congo Republic

“…Hypothesis testing was also carried out to statistically compare the mean values obtained for each participating CT facility [9][10][11]. The null hypothesis was that two compared data sets were drawn from the same population with the same mean (H0: µx -µy = 0), while the alternative hypothesis was that two compared data sets were drawn from different populations with different means (H1: µx ≠ µy).…”

Indoor Radon Testing, Effective Dose and Mitigation Measures in a Residential House of a Mining Area

“…Average annual human exposure (effective dose) to all natural radioactive sources is estimated to be 2.4 mSv, and about 52% of this exposure is caused by the inhalation of radon [7]. Many studies have been conducted worldwide to evaluate the radiation dose to inhabitants caused by radon [8][9][10][11]. Previous studies in the area of Kosovska Mitrovica have also shown increased indoor radon concentrations in dwellings, which the authors have indicated a radon-prone area [12][13][14].…”