Natural gamma-emiting radionuclides in Pakistani Portland cement

Studies of the natural gamma-emitting radionuclides in Portland cement manufactured in the North West Frontier Province (NWFP) of Pakistan and the various raw materials which compose the product have been carried out using gamma-spectrometric techniques. For data acquisition a high-purity germanium detector (HPGe) was used. The range of the total specific activity (minimum and maximum values) due to all the three radionuclides (K-40, Ra-226 and Th-232) were found to be 187.8 +/- 63.5-573.2 +/- 73.1 Bq kg(-1) (Portland cement); 54.5 +/- 16.1-183.9 +/- 31.4 Bq kg(-1) (limestone); 87.1 +/- 30.7-297.1 +/- 64.4 Bqkg(-1) (gypsum); 696.4 +/- 79.1-1043.9 +/- 85.0 Bqkg(-1) (slate); and 490.9 +/- 54.5-570.2 +/- 59.8 Bqkg(-1) (latrite). The average specific activities due to K-40 in Portland cement and all the raw materials were found to be higher when compared with Ra-226 and Th-232. Such materials do not pose any excess radiological health problem. (C) 2001 Elsevier Science Ltd. All rights reserved.