Natural Radioactivity of Topsoil in Two Granite Areas of Guangzhou, South China

Abstract:

The natural radionuclide (²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K) concentrations in 152 soil samples were determined from two major granite areas in Guangzhou, using high resolution γ-ray spectroscopic system based on the characteristic spectral peaks. The mean activity values for ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K were found to be 156.6±98.8, 160.9±96.5, 184.8±101.5 and 832.5±493.1 Bq kg^–1 dry mass, respectively. The absorbed dose rate (D) calculated from activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K ranged from 53.2 to 497.1 nGy h^–1 with a mean of 220.7 nGy h^–1. The Radium equivalent activity (Ra_eq), the outdoor annual effective dose and the external hazard index (I_r), which resulted from the natural radionuclides in soil, were also calculated and found to vary from 119.7 to 1117.2 Bq kg^–1, from 0.07 to 0.61 mSv and from 0.33 to 3.07, respectively. The radium equivalent activities and the external hazard index in all the soil samples were same as 64.5% higher than the limit of 370 Bq kg^–1 and 1.0, respectively. The outdoor annual effective dose was higher than the worldwide mean value of 0.07 mSv.

• Periodical: Advanced Materials Research (Volumes 955-959)
• Pages: 3691-3695
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.955-959.3691
• Online since: June 2014
• Authors: Gang Song*, Min Xing Lu, Qiu Ping Zhu, Di Yun Chen, Yong Heng Chen
• Keywords: Absorbed Dose Rates, Annual Effective Dose, External Hazard Index, HPGe-γ Detector, Natural Radioactivity, Radium Equivalent Activity

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