Baseline TENORM/NORM Survey for Radionuclide Concentration and Background Ionizing Radiation at Seplat Energy Facilities

Abstract

This baseline survey assesses TENORM/NORM and background ionizing radiation at Seplat Energy facilities in Nigeria. Soil activity concentrations of 238U, 266Ra, 238U and 40K in Seplat West often exceeded UNSCEAR (2000) world averages (35 BqKg-1 for 238U and 226Ra, 30 BqKg-1 for 232Th, 400 BqKg-1 for 40K), with ranges including 3.30±0.2 to 61.03±3.08 BqKg-1 for 238U, 7.62±0.45 to 80.25±3.41 BqKg-1 for 226Ra, 0.28±0.03 to 92.07±4.59 BqKg-1 for 232Th and BDL to 1772.8±91.3 BqKg-1 for 40K. In Seplat East, 238U, 226Ra and 232Th were slightly above averages, while 40K was below. Absorbed dose rates exceeded the world average of 59 nGyh-1 except for SOM at Oben and SJWL/S at Jisike. Annual effective doses exceeded 0.07 mSvy-1 except at SOM and SOHSP. Radium equivalent (Raeq) values were below 370 BqKg-1, and external, internal, and gamma indices were all less than unity. Excess lifetime cancer risk (ELCR) values exceeded the world average of (UNSCEAR, 2000).