Preliminary Radiological Survey on High Rare-earth Containing Area in San Vicente, Philippines
Kazuki Iwaoka1*, Lorna Jean H. Palad2, Christopher O. Mendoza2,
Fe M. Dela Cruz2, Masahiro Hosoda3,4, Shinji Tokonami4, Eliza B. Enriquez2,
Chitho P. Feliciano2, and Reiko Kanda1
1National Institutes for Quantum and Radiological Sciences and Technology
4-9-1 Anagawa, Inage, Chiba 263-8555 Japan
2Health Physics Research Section, Atomic Research Division
Department of Science and Technology – Philippine Nuclear Research Institute (DOST-PNRI)
Commonwealth Avenue Diliman, Quezon City 1101 Philippines
3Hirosaki University Graduate School of Health Sciences
66-1 Honcho, Hirosaki, Aomori 036-8564 Japan
4Institute of Radiation Emergency Medicine, Hirosaki University
66-1 Honcho, Hirosaki, Aomori 036-8564 Japan
*Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.
ABSTRACT
Erawan Beach area in San Vicente, Palawan Island, Philippines contains rare-earth elements and natural radioactive nuclides at high levels. If the development of mineral resources starts, environmental impacts will be a significant concern for residents in the area. In this study, a preliminary radiological survey on ambient dose equivalent rate and dust concentration was performed in the Erawan Beach area. The ambient dose equivalent rates in each site ranged from 0.060 to 0.81 µSv h−1. External gamma radiation exposures estimated from these values were lower than the reference level range (1−20 mSv y−1) for abnormally high levels of natural background radiation described in the ICRP Publication 103. The dust concentrations in each site ranged from 0.40 to 0.76 mg m−3, which were relatively higher than the typical dust concentration in air (0.05 mg m−3). Based on estimation from the results of the ambient dose equivalent rates and dust concentrations, inhalation radiation exposure due to natural radioactive nuclides in dust will likely be less than external gamma radiation exposure.
INTRODUCTION
An area containing natural radioactive nuclides at high levels exists in the Philippines. Because this area − which is located in Erawan Beach in San Vicente, Palawan Island − is composed of the mineral resource called allanite, including rare-earth elements mainly, investigations of metal resources have been performed so far (Reyes et al. 2013). If the development of mineral resources starts in the Erawan Beach area, environmental impacts might be resident's strong concerns. Therefore, it is essential to obtain radiological data in the Erawan Beach area so that residents feel a sense of safety, and workers develop mineral resources safely. In this study, a preliminary radiological survey on ambient dose equivalent rate and dust concentration was performed in the Erawan Beach area. . . . read more
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