Radiochim. Acta 2019; aop Muneer Aziz Saleh*, Ahmad Termizi Ramli, Khaidzir Bin Hamzah, Jasman Zainal, Mohsin Mohd Sies, Hamman Tukur Gabdo and Nuraddeen Nasiru Garba In situ measurement of terrestrial gamma dose rates in eastern region of Peninsular Malaysia and its relation to geological formation and soil types https://doi.org/10.1515/ract-2018-2950 Received February 26, 2018; accepted December 7, 2018 Abstract: This present study aims to obtain baseline data of environmental terrestrial radiation and to assess the cor- responding health risk in the ambient environment in east- ern region of Peninsular Malaysia. The measurements were taken 1 m above the soil surface using NaI [Ti] detector with a total of 2144 measured points which covered all geologi- cal formations and soil types. The measured gamma dose rates ranged from 26 nGy h −1 to 750 nGy h −1 with a mean value of 172 ± 90 nGy h −1 . The mean gamma dose rate is three times higher than world averages of 57 nGy h −1 . The data of gamma dose rates show the reading of the gamma dose rates not fit to the normal distribution. The variations of gamma dose rates based on geological formation and soil types were investigated using the unbalanced one way ANOVA. The results indicated strong significant differ- ences due to the different geological formations and soil types. The T-test of gamma dose rates for each pair of soil types or geological formations and their hypothesis test at 95 % confidential level were compared to shows the sig- nificant difference between each pairs. The results indicate that the gamma dose rates for all pairs of soil types were significant differed except the miscellaneous soil while the gamma dose rates of the pairs of geological formation were also significant differed except the intermediate and intrusive geological formations. Acid intrusive and inter- mediate intrusive geological formations has the highest mean values of 223 nGy h −1 and 278 nGy h −1 , respectively. These values are approximately four and five times the world average. Soil type (Steep land) has the highest gamma dose rate with the mean value of 215 nGy h −1 . The radiological health information which are the total annual effective dose equivalent, the collective effective dose, life- time effective dose and the lifetime cancer risk for each person are 0.844 mSv, 3.53 × 10 3 man Sv y −1 , 59.10 mSv and 3.25 × 10 −3 , respectively. The results in eastern region of Peninsular Malaysia were comparable to different areas in Malaysia, which indicate the value reported in UNSCEAR, 2000 should be adjusted to the current status in Malaysia. Keywords: Natural radiation, gamma dose rates, geologi- cal formations, soil types, ANOVA, T-test. 1 Introduction Radiation sources classify to two sources: natural and man-made. The natural radiation sources classify to ter- restrial radiation and cosmic radiation. They cause both external and internal exposures. Exposure to ionizing radiation from natural sources is a continuous and una- voidable feature of life. The natural background radiation exposure to the human body daily comes from the food, air, elements in the body, building materials, ground and outer space [1]. Gamma radiation emitted from primordial radionuclides and their progenies are one of the main external sources of radiation exposure to humans. Gamma dose rate (GDR) depend primarily on the geo- logical formation and soil type of the location; and these factors (geology and soil type) greatly influence the dose distribution from natural terrestrial radiation [1, 2]. Since natural radiation is the largest contributor of external dose to the world population, assessment of gamma radiation dose from natural sources is of particular importance. 238 U(series), 232 Th (series) and 40 K are the main terrestrial radionuclides contributor to external dose rate, while *Corresponding author: Muneer Aziz Saleh, Nuclear Engineering Programme, School of Chemical and Energy Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johore Bahru, Johor, Malaysia; and National Atomic Energy Commission (NATEC), Sana’a, Yemen, E-mail: mouneersaleh@yahoo.com Ahmad Termizi Ramli: Physics Department, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johore Bahru, Johor, Malaysia Khaidzir Bin Hamzah, Jasman Zainal and Mohsin Mohd Sies: Nuclear Engineering Programme, School of Chemical and Energy Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johore Bahru, Johor, Malaysia Hamman Tukur Gabdo: Department of Physics, Federal College of Education, Yola, Nigeria Nuraddeen Nasiru Garba: Department of Physics, Ahmadu Bello University, Zaria, Nigeria Brought to you by | provisional account Unauthenticated Download Date | 1/22/19 5:10 PM