Preliminary assessment of natural radioactivity and associated radiation hazards in a phosphate mining site in southern area of Togo
Because of the increasing use of phosphate in industries worldwide, especially in Togo, it is interesting to investigate the potential radioactivity exposure of phosphate ores, especially in the one being exploring in Togo nowadays.
Material and methods
The contents of natural radionuclides (40K, 226Ra, 232Th, 235U and 238U) were assessed in phosphate soil samples from Kpogamé, Dagbati and Kpémé in the maritime region of Togo by using gamma spectrometry-based Broad Energy Germanium detector (BEGe6530). Since no study was made prior to the exploitation, the samples from the control area of Anfoin-Kpota far away from the three others were considered as reference.
Results and discussion
The results are discussed and compared with the data from other countries. The activity concentration of 40K, 226Ra, 232Th, 235U and 238U are between (59.45 and 129.99), (20.19 and 779.93), (16.81 and 121.42), (2.26 and 52.03) and (16.66 and 841.14) Bq kg−1, respectively. The values obtained shows that the exploitation sites (Dagbati and Kpogamé) and treatment site (Kpémé) have a very high level of radioactivity than the control area (Anfoin-Kpota). The Kpogamé and Dagbati exploitation and Kpémé waste discharging phosphate deposit sites were found to have higher activity concentration than many others exploited phosphate sedimentary deposits around the world. The average annual effective dose of the above studied sites is 0.36, 0.24 and 0.48 mSv year−1, respectively. The value related to the discharge waste site is about 2% of the 1.0 mSv year−1 recommended by the International Commission on Radiological Protection as the maximum annual dose to the public.
The obtained result of both radioactivity and radiological level in the studied areas will be considered as a pre-operational baseline to estimate the possible radiological impacts due to mining and processing phosphate industrial activities.
KeywordsPhosphate Gamma spectrometry BEGe6530 detector Soil Radiation hazard
The authors wish to express their deep appreciation and gratitude to the IAEA for awarding the fellowship, without which this work would have been impossible; and the Director General of the National Radiation Protection Agency of Cameroon, Dr. Augustin SIMO for the laboratory support. The authors also appreciate the community of Hahotoé-Kpogamé for the understanding during sampling period. They also wish to thank Dr. Michel WARNAU, Programme Management Officer for IAEA to Togo for his understanding and availability to this work. We also wish to address special thanks to Col. MANZI Pidalatan, National Liaison Officer of Togo and project coordinator of IAEA TC Project Number: TOG/0/002 provided in granting access to the facilities to successfully complete this study.
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