Skip to Main content Skip to Navigation
Journal articles

$^{226}$Ra, $^{232}$Th and $^{40}$K contents and radon exhalation rate from materials used for construction and decoration in Cameroon

Abstract : This work deals with the measurement of radioactivity and radon exhalation rate from building materials manufactured in Douala city from geological materials. Nine types of building material were surveyed for their natural radioactivity contents using high-resolution gamma-ray spectrometry. The activity concentrations for Ra-226, Th-232 and K-40 varied from 11.5 to 49 Bq kg(-1), 16 to 37 Bq kg(-1) and 306 to 774 Bq kg(-1), respectively. The absorbed dose rate in the samples investigated at 1 m above ground level ranged from 28.5 to 66.6 nGy h(-1). External and internal hazard indices were also estimated as defined by the European Commission. The Ra equivalents of the materials studied ranged from 57.5 to 133 Bq kg(-1) and are much smaller than the recommended limit of 370 Bq kg(-1) for construction materials for dwellings. Polycarbonate nuclear track detectors (NTDs), type CR-39, were used for measuring the radon concentration from different materials. In fact, knowledge of the radon exhalation rate from building materials is important for understanding the individual contribution of each material to the total indoor radon exposure. Samples were hermetically closed in glass vessels and the radon growth was followed as a function of time. The radon exhalation rate was therefore derived from the experimental measurement of a-track densities. The radon exhalation varied from (5.77 +/- 0.06) x 10(-5) to (7.61 +/- 0.07) x 10(-5) Bq cm(-2) h(-1) in bricks, from (5.79 +/- 0.05) x 10(-5) to (11.6 +/- 0.12) x 10(-5) in tiles, and was (6.95 +/- 0.03) x 10(-5) Bq cm(-2) h(-1) in concrete. A correlation (correlation coefficient similar or equal to 0.8) was found between radium concentration measured with a HPGe detector and the radon exhalation rate obtained using nuclear track detectors
Document type :
Journal articles
Complete list of metadatas
Contributor : Yvette Heyd <>
Submitted on : Monday, September 8, 2008 - 11:25:07 AM
Last modification on : Friday, May 8, 2020 - 1:09:47 AM

Links full text




M. Ngachin, M. Garavaglia, C. Giovani, A. Nourreddine, M. G. Kwato Njock, et al.. $^{226}$Ra, $^{232}$Th and $^{40}$K contents and radon exhalation rate from materials used for construction and decoration in Cameroon. Journal of Radiological Protection, IOP Publishing, 2008, 28, pp.369-378. ⟨10.1088/0952-4746/28/3/007⟩. ⟨in2p3-00319352⟩



Record views