Nature of radon, radium, exhalation and uranium concentration from construction materials used in Al Jouf city, Saudi Arabia

This study aims to assess seven group samples used as building materials in the Saudi Arabian market in Al Jouf city had their radon concentration, exhalation rate, radium activity, as well as the risk of death due to cancer in excess of the natural background risk due to exposure to carcinogens over a period of a lifetime (Excess Lifetime Cancer Risk), and uranium content measured. The 'Can technique' was employed, which is based on the use of Solid State Nuclear Track Detectors (SSNTDs) CR-39. The average level of radon concentrations (Bq/m3) for the materials under investigation are as follows: 99.40 +/- 10.26 (Soil), 146.92 +/- 12.49 (Cement), 115.68 +/- 11.13 (Gypsum), 132.28 +/- 11.89 (Ceramic), 223.24 +/- 14.8 (Marble), 210.85 +/- 14.72 (Bricks), and 241.71 +/- 15.65 (Gravel) at Bq. m-3. The results indicate that radon levels in Soil, Cement, Gypsum, and Ceramics are below the allowed limit of exposure to radon for humans, set at 200 Bq. m- 3, while in the cases of Marble, Bricks and Gravels, have been higher than the allowed limit. Results for Annual Effective Dose came in as follows: Soil = 2.09 mSv/y; Cement = 3.09 mSv/y; Gypsum = 2.43 mSv/y; Ceramic = 2.78 mSv/y; Marble = 4.69 mSv/y; Bricks = 4.43 mSv/y and finally, Gravel = 5.08 mSv/y. These measurements were higher than the global average (1 mSv/y). The average annual cancer risk of the samples measured, were as follows: 8.05 (Soil); 11.89 (Cement); 9.36 (Gypsum); 10.71 (Ceramic); 18.07 (Marble); 17.07 (Bricks) and finally, 19.56 (Gravel). The average mass exhalation rates and surface exhalation for the materials under investigation are as follows: (0.08 Bq kg- 1h- 1 - 3.95 Bq m- 2 d-1) for (Soil), (0.18 Bq kg- 1h-1 - 5.85 Bq m- 2 d- 1) for Cement, (0.20 Bq kg- 1h- 1- 4.60 Bq m- 2 d-1) for Gypsum, (0.08 Bq kg- 1h- 1- 4.26 Bq m- 2 d-1) for Ceramic, (0.19 Bq kg- 1h- 1- 8.88 Bq m- 2 d-1) for Marble, (0.18 Bq kg- 1h-1- 8.39 Bq m- 2 d- 1) for Bricks and (0.18 Bq kg- 1h- 1- 9.62 Bq m- 2 d-1) for Gravel. The mean estimated values for the radium activity were 30.6 +/- 3.18 Bqkg-1 (Soil); 67.6 +/- 5.66 Bqkg-1 (Cement); 73.9 +/- 6.99 Bqkg-1 (Gypsum); 47.8 +/- 4.20 Bqkg-1 (Ceramic); 70.1 +/- 4.57 Bqkg-1 (Marble); 66.8 +/- 4.7 Bqkg- 1 (Bricks) and 67.4 +/- 4.40 Bqkg-1 (Gravel). From a health hazard viewpoint, the results showed that the samples under review are safe and are not life-threatening. The mean estimated values for the uranium content are as follows: 1.35 ppm (Soil); 2.98 ppm (Cement); 3.26 ppm (Gypsum); 2.11 ppm (Ceramic); 3.09 ppm (Marble); 2.94 ppm (Bricks) and 2.97 ppm (Gravel).