Assessment of radiological hazards due to the presence of natural radionuclides in samplesof building materials collected from the northwestern areas of Pakistan

Abstract

Brick, sand, marble and cement are mainly used for the construction ofdwellings in Pakistan. Therefore, knowledge of the presence of naturalradioactivity in these materials is of great importance in order to assess theradiological hazards associated with them. In this context, specific activities of226Ra,232Th and 40K were measured in brick, sand, marble and cement samples collected from different localities of theNorth West Frontier province and federally administered tribal areas, Pakistan, using a P-typecoaxial high-purity germanium spectrometer. In brick samples, the average measured activities for226Ra,232Th and 40K were 30 ± 15, 41 ± 21 and 523 ± 182 Bq kg−1, whereas in sand samples, these values were19 ± 9,30 ± 15 and 769 ± 461 Bq kg−1, respectively. In marble samples, the average specific activities of226Ra,232Th and40K werefound to be 18 ± 19, 18 ± 21 and 299 ± 328 Bq kg−1, whilst in cementsamples they were 24 ± 6, 18 ± 4 and 244 ± 29 Bq kg−1, respectively. Radium equivalent activities were also calculated and were found to be129 ± 54,121 ± 57,67 ± 60 and 68 ± 9 Bq kg−1 forbrick, sand, marble and cement samples, respectively. The annual average effective doses from these sampleswere 0.37 ± 0.15, 0.33 ± 0.15, 0.20 ± 0.17 and 0.20 ± 0.03 mSv, respectively. External and internal hazard indices were less than one for all thesamples studied.