An-Najah Staff

Background:  Many public health agencies rank residenal radon exposure as the second leading cause of lung cancer aer cigaree smoking. It has been shown that the risk coefficient for lung cancer is higher for children than that for adults. Therefore, indoor radon measurements were carried out in the elementary schools of Tulkarem province, West Bank, Palesne. Materials and Methods: Two hundred and thirty solid state nuclear track detectors (SSNTDs) type CR-39 were distributed in the classrooms of 20 elementary schools in Tulkarem province area. About thirty of them were used for quality assurance purposes. The CR-39 detectors were exposed in the schools for three months during the school summer holiday from May 2012 to August 2012 and then collected and etched in Sodium Hydroxide (NaOH) 6.25 N soluon at 75 °C for 6 h. The tracks were counted manually at the digital microscope. Results: The indoor radon levels were generally low, ranging from 3.48 to 210.51 Bq/m3 (Becquerel per cubic meter), with a mean radon concentraon (mean±SE; standard error) of 40.42± 2.49 Bq/m3. The average annual radon effecve dose was assessed to be (mean±SE) 0.17 ± 0.01 mSv/y (milliSievert per year) while the excess lifeme lung cancer risk was approximately 0.09%. The results obtained indicate that the indoor radon concentraon was significantly affected by the floor level of the classroom (negavely correlated) and the school building age (posively correlated). Conclusion: The radon concentraon and the resulng dose in the schools were within the reference levels of the Internaonal Commission on Radiological Protecon (ICRP). Beer venlaon is recommended to decrease the risk to the minimum. 

 Indoor radon has been recognized as one of the health hazards for mankind because long-term exposure to radon increases the risk of developing lung cancer. This study aims at assessing the contribution of building materials towards the total indoor radon exposure to the inhabitants of Nablus district, Palestine. The radon exhalation rate has been carried out for different building materials of international origin used in construction in Nablus district. The “closed-can technique” has been employed in this study using solid state nuclear track detectors (CR-39). After 100 days of exposure, CR39  detectors were etched chemically and then counted under an optical microscope. Results show that Radon exhalation rates from granite and marble have relatively high values as compared to other building materials followed- in order- by cement, ceramic, concrete, building stones, and porcelain, while gypsum, sand, gravel and bricks contribute less to radon exhalation rate which was found to range from (55.37 ± 15.01) mBq/m 2 h for gypsum samples to (589.54 ± 73.24) mBq/m 2 h for granite samples, with a total average value of (268.56 ± 166.21) mBq/m 2 h. The corresponding radon concentration, effective radium content, and annual effective dose average values were (148.49 ± 91.13) Bq/m 3 , (1.93 ± 1.20) Bq/Kg and (3.74 ± 2.30) mSv/y, respectively. In general, the radon exhalation rate from the investigated building materials is low and under the global value except for granite, marble and some cement samples and thus except for the excluded, the studied materials are safe as construction materials.