Radiological Hazards for Marble and Granite Used at Shak El Thouban Industrial Zone in Egypt

Amany T Sroor,Saher M Darwish,Samia M El-Bahi,Mohamed G Abdel Karim

doi:10.4236/jep.2013.412a005

Abstract

The background level of radiation in the natural environment surrounds us at all times. Levels of natural occurring radioactivity in marble and granite used at Shak El Thouban industrial zone in Cairo, Egypt have been investigated using HPGe detector through gamma-ray spectrometry. The activity concentration of radionuclides in the 238U-, 232Th-series and 40K has been determined. The average activity concentration of 238U, 232Th and 40K for marble samples was 23.77 Bq/kg ranged from (10.91 to 45.4), 10.75 Bq/kg ranged from (5.46 to 23.61) and 520.43 Bq/kg ranged from (382.30 to 1132.41), respectively. The 238U, 232Th and 40K activity concentration for granite samples were 54.31 Bq/kg ranged from (12.04 to 106.34), 113.57 Bq/kg ranged from (23.91 to 270.36) and 7867.51 Bq/kg ranged from (2017.60 to 11436.91), respectively. Concerning the radiological risk, the radium equivalent activity, external and internal radiation hazard indices, the radiation level index and absorbed dose rate were evaluated. The mass exhalation rates of 222Rn and emanation coefficient have been also calculated. The mass exhalation rate of radon was found to be from 14.86 to 137.13 and 16.48 to 155.26 μBq/kg·s for marble and granite samples, respectively. The mean values of the specific activity of 226Ra, activity of 238U before and after sealing time and the mass exhalation rate of radon for granite samples are twice that for marble samples. All radiological indices and the mass exhalation rate of radon are lower than the permissible levels for building material in all marble samples, while all granite samples are higher and unsafe and pose a risk to the workers and users of these products due to the emanation of radon that may accumulate by time, especially in closed spaces.

Highlights

Since the Earth formed and life developed, background radiation has been our constant companion
The present study aims to determine the activity concentration of 238U, 232Th and 40K of twenty six marble and granite samples wide locally used at Shak El Thouban industrial zone in Egypt, using hyper pure germanium (HPGe) detector in a low background configuration
It is clear that the activity concentrations of 238U, 232Th and 40K in marble samples are within the permissible levels 50, 50 and 500 Bq/kg [12], while that in granite samples are higher than the permissible levels

Summary

Introduction

Since the Earth formed and life developed, background radiation has been our constant companion. Primordial radionuclides are found around the globe in igneous and sedimentary rock. These radionuclides migrate from rocks into soil, water, and even air. Human activities such as uranium mining have redistributed these radionuclides. Primordial radionuclides include the series of radionuclides produced when uranium and thorium decay, as well as potassium-40. The specific activities of 238U, 232Th and 40K in building raw materials (such as cement, brick, concrete, soil, marble, granite, sand, etc.) mainly depend on their geological sites of origin and their geochemical characteristics. Knowledge of radiation levels and basic radiological parameters in building materials is essential to assess possible risks to human health

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Conclusion