Radioactivity Investigation of Sand from the Northern Region of Tlemcen-Algeria, Using Well-Shape NaI(Tl) Detector

Abstract

The presence of natural radioactivity in sand and other building materials results in internal and external exposure to the general public. Therefore, it is desirable to determine the concentration of naturally occurring radionuclides. Sand is one of the main components in building construction beside cements, granites and bricks. Thus, this research has been carried out in order to investigate the levels of natural radioactivity and associated radiation hazard in some Algerian sand. The natural radioactivity due to the presence of ²²⁶Ra, ²³²Th and ⁴⁰K in sand samples used as building materials in Tlemcen province - Algeria was measured by gamma spectrometry using NaI(Tl) scintillation well-shaped detector. In this context, sand samples were collected from four different locations of northern areas of Tlemcen city, Behira seabeach sand, Targa sand, Boukdasen sand, Sidi Bourzin sand. The measured activity in the sand samples ranged from 4.70 to 7.85 Bq.kg^-1, 0.80 to 3.00Bq.kg^-1 and 22 to 53 Bq.kg^-1 for ^226Ra, ²³²Th and ⁴⁰K, respectively. The concentrations of these natural radionuclides were compared with the reported data for other countries and were found significantly lower than the worldwide average as reported by United Nations Scientific Committee on the Effects of Atomic Radiation (1,2). Radium equivalent activities were calculated (9.25 to 16.39) Bq·kg^–1for the analyzed samples to assess radiation hazards arising due to the presence of these radionuclides in the samples. Most of the calculated radium equivalent activities are lower than the limit set in the OECD report at 370Bq.kg^–1(3). The measured representative level index values for the investigated samples varied in the range (0.068 to 0.118) Bq.kg^-1. External and internal hazard index (H_ex,H_in), the specific dose rates indoor (D) and the annual effective dose (DE) due to gamma radiation from building materials was calculated.

Keywords. Sand, natural radioactivity, gamma radiation, absorbed dose, radiation exposure, Potassium, Thorium, Uranium, NaI(Tl) Detector, Tlemcen.