Gamma spectroscopic assay of soil samples from waste dump sites in Port Harcourt, Nigeria

A lead shielded 7.6 cm×7.6 cm NaI (Tl) detector and a Canberra Multichannel Analyzer were employed for a gamma spectrometric assay of 100 soil samples from refuse dump sites in Port Harcourt city and environs. The massic activities of 40K, 226Ra and 228Ra were determined and found to correspond to natural levels of some 10 Bq/kg. No gamma-emitting anthropogenic radionuclides were detected. The mean radium equivalent is 44.2 Bq/kg giving a dose rate of 24.6 μSv/year.