Natural radioactivity measurements in building materials in Southern Lebanon

Abstract Using γ-spectroscopy and CR-39 detector, concentration C of naturally occurring radioactive nuclides 226 Ra, 222 Rn, 214 Bi, 228 Ac, 212 Pb, 212 Bi and 40 K, has been measured in sand, cement, gravel, gypsum, and paint, which are used as building materials in Lebanon. Sand samples were collected from 10 different sandbank locations in the southern part of the country. Gravel samples of different types and forms were collected from several quarries. White and gray cement fabricated by Shaka Co. were obtained. γ-Spectroscopy measurements in sand gave Ra concentration ranging from 4.2 ± 0.4 to 60.8 ± 2.2 Bq kg −1 and Ra concentration equivalents from 8.8 ± 1.0 to 74.3 ± 9.2 Bq kg −1 . The highest Ra concentration was in gray and white cement having the values 73.2 ± 3.0 and 76.3 ± 3.0 Bq kg −1 , respectively. Gravel results showed Ra concentration between 20.2 ± 1.0 and 31.7 ± 1.4 Bq kg −1 with an average of 27.5 ± 1.3 Bq kg −1 . Radon concentration in paint was determined by CR-39 detector. In sand, the average 222 Rn concentration ranged between 291 ± 69 and 1774 ± 339 Bq m −3 among the sandbanks with a total average value of 704 ± 139 Bq m −3 . For gravel, the range was found to be from 52 ± 9 to 3077 ± 370 Bq m −3 with an average value of 608 ± 85 Bq m −3 . Aerial and mass exhalation rates of 222 Rn were also calculated and found to be between 44 ± 7 and 2226 ± 267 mBq m −2  h −1 , and between 0.40 ± 0.07 and 20.0 ± 0.3 mBq kg −1  h −1 , respectively.