Gamma Spectroscopy Analysis of Produced Water from Selected Flow Stations in Delta State, Nigeria

Abstract

This paper present the findings of naturally occurring radionuclides (226Ra, 228Ra and 40K) carried out on produced water collected from seven oil and gas fields onshore of Delta State, using gamma spectroscopy. Twenty- one produced water samples from seven flow stations waste pit were collected within the oil fields using standard methods. The average specific activity concentrations for the radionuclides 40K, 226Ra and 228Ra are 48.7813.67Bql-1, 6.042.48Bql-1 and 5.182.14Bql-1 respectively. These obtained values are higher than the WHO, 2008 recommended standard limit of 10Bql-1, 1.0Bql-1 and 0.1Bql-1 for 40K, 226Ra and 228Ra respectively. Radium equivalent have average activity concentration of 14.365.55Bql-1 while the average absorbed dose rate of 6.68mSvy-1 was found to be higher than the UNSCEAR 2000 acceptable standard of 1.5mSvy-1. Although the hazard indices (Hex, Hin) calculated are still within their tolerable levels, the estimated committed effective dose due to intake of the sampled water for all the produced water considered are far above the ICRP 0.1 mSvyr-1 maximum permissible limit. The result indicates some level of water pollution in the studied water samples. This work will add to the world data base of natural radionuclide in produced water from crude oil.