Radiological implications of granite of northern Pakistan

Abstract

Granite is an igneous rock that contains natural radioactivity of primordial radionuclides.In Pakistan, granite is distributed in a vast area called the Ambela Granitic Complex(AGC) in North West Frontier Province (NWFP). Granite is a hard rock that exists indifferent colours and is used to decorate floors, kitchen counter tops, etc. The use of granitein a building as a decor material is a potential source of radiation dose; therefore,natural radioactivity has been measured in 20 granite samples of the AGC with anHPGe (high purity germanium) based gamma ray spectrometer. The averagespecific activities and their range (given in parentheses) for primordial radionuclides40K,226Ra and232Th were 1218 (899–1927),659 (46–6120) and 598 (92–3214) Bq kg−1, respectively. The measured activity concentrations were used for the assessment of hazardindices and radiation dose which were evaluated based on the permissible limits defined forthese parameters. The measured specific activities and the derived quantities, hazardindices and radiation dose, have been compared with those given in the literature for theseparameters.