Natural radioactivity levels in soils, rocks and water at a mining concession of Perseus gold mine and surrounding towns in Central Region of Ghana.

A Faanu,D O Kpeglo,L Agyeman,L Tettey-Larbi,E O Darko,R Kpodzro,P A Amoah,R A Awudu,C Kansaana,G Emi-Reynolds,O K Adukpo,A O Efa,A D Ibrahim,B Agyeman,H Lawluvi

doi:10.1186/s40064-016-1716-5

A Faanu, D O Kpeglo + Show 13 more

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https://doi.org/10.1186/s40064-016-1716-5

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Journal: SpringerPlus	Publication Date: Feb 1, 2016
Citations: 45	License type: CC BY 4.0

Affiliation: Ghana Atomic Energy Commission

Abstract

Levels of naturally occurring radioactive materials prior to processing of gold ore within and around the new eastern concession area of Perseus Mining (Ghana) Limited were carried out to ascertain the baseline radioactivity levels. The study was based on situ measurements of external gamma dose rate at 1 m above ground level as well as laboratory analysis by direct gamma spectrometry to quantify the radionuclides of interest namely; 238U, 232Th and 40K in soil, rock, ore samples and gross alpha/beta analysis in water samples. The average absorbed dose rate in air at 1 m above sampling point using a radiation survey metre was determined to be 0.08 ± 0.02 μGyh−1 with a corresponding average annual effective dose calculated to be 0.093 ± 0.028 mSv. The average activity concentrations of 238U, 232Th, and 40K in the soil, rock, and ore samples were 65.1 ± 2.2, 71.8 ± 2.2 and 1168.3 Bqkg−1 respectively resulting in an average annual effective dose of 0.91 ± 0.32 mSv. The average Radium equivalent activity value was 257.8 ± 62.4 Bqkg−1 in the range of 136.6–340.2 Bqkg−1. The average values of external and internal indices were 0.7 ± 0.2 and 0.9 ± 0.2 respectively. The average gross alpha and gross beta activity concentrations in the water samples were determined to be 0.0032 ± 0.0024 and 0.0338 ± 0.0083 Bql−1 respectively. The total annual effective dose from the pathways considered for this study (gamma ray from the soil, rock and ore samples as well as doses determined from the gross alpha/beta activity concentration in water samples) was calculated to be 0.918 mSv. The results obtained in this study shows that the radiation levels are within the natural background radiation levels found in literature and compare well with similar studies for other countries and the total annual effective dose is below the ICRP recommended level of 1 mSv for public exposure control.

Highlights

Artificial and natural radioactivities are the two main sources of radiation exposure.Human activities such as mining and mining processes, oil and gas extraction may result in situations where the radioactivity levels of materials that contain natural radionuclidesFaanu et al SpringerPlus (2016) 5:98 are significant enough to warrant regulatory control (UNSCEAR 2000; IAEA 2005)
The results of the absorbed dose rates in this study compare well with the range of dose rates values reported for other countries (UNSCEAR 2000) as well as results from similar studies carried out in other mines in Ghana
The average annual effective doses estimated from direct external gamma-ray exposure from natural radioactivity at 1 m above sampling area and that due to activity concentrations of 238U, 232Th and 40K in the soil and rock-ore pad samples were 0.093 ± 0.028 and 0.91 ± 0.32 mSv respectively

Summary

Introduction

Artificial and natural radioactivities are the two main sources of radiation exposure.Human activities such as mining and mining processes, oil and gas extraction may result in situations where the radioactivity levels of materials that contain natural radionuclidesFaanu et al SpringerPlus (2016) 5:98 are significant enough to warrant regulatory control (UNSCEAR 2000; IAEA 2005). Artificial and natural radioactivities are the two main sources of radiation exposure. Human activities such as mining and mining processes, oil and gas extraction may result in situations where the radioactivity levels of materials that contain natural radionuclides. Faanu et al SpringerPlus (2016) 5:98 are significant enough to warrant regulatory control (UNSCEAR 2000; IAEA 2005). The two main sources of natural radiation exposure are from terrestrial radionuclides and cosmogenic radionuclides. They lead to external and internal radiation exposure. This study focused on levels of radioactivity due terrestrial radionuclides. The radionuclides of interest are Uranium-238 and Thorium-232 and their decay series nuclides as well as Potassium-40

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