Measurement of radionuclides in surface soil and beach sand samples from Rayong Province (Thailand) and the evaluation of excess lifetime cancer risk

Abstract

Specific activities of natural ( 40 K, 226 Ra, and 232 Th) and anthropogenic ( 137 Cs) radionuclides in 230 surface soil and beach sand samples collected from the densely populated areas of industrial activities in Rayong Province, Thailand, were analyzed. Experimental results were obtained using a high-purity germanium detector and gamma spectrometric analysis system. The frequency distributions of the four radionuclides were investigated and calculated as suitable medium values of all distributions. According to asymmetrical distribution, medium values of the specific activities of all required radionuclides should be median values. Furthermore, the median values of the three natural radionuclides were also used to evaluate absorbed dose rates in the air (D), radium equivalent (Ra eq ), external hazard index (H ex ), annual effective dose rate (AED out ), and excess lifetime cancer risk (ELCR) in the studied areas. The results were compared with data obtained from the annual report of Thailand's Office of Atoms for Peace, the global radioactivity measurements, and the evaluations and recommended values proposed by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). It was found that most of the results were significantly lower than the recommended values of UNSCEAR except for the median value of specific activity of 226 Ra. Moreover, the radioactive contour map for the investigated areas was constructed.

An In-Depth Examination of the Natural Radiation and Radioactive Dangers Associated with Regularly Used Medicinal Herbs

“…Gamma-ray spectrometry was used to measure the radioactivity levels of NORMs in 29 different medicinal plants that are commonly used in Egypt. The equation used to figure out the average concentrations of 226 Ra, 232 Th and 40 K that were used (3). Calculations were also used to figure out how much radiation these medicinal plants might cause.…”

“…In this formula, Y is efficiency, a, b, c, d, e, f are constants, and x is the gamma ray energy in KeV. Y = a + b (Lnx) + c (Lnx) 2 + d (Ln x) 3 + e (Lnx) 4 + f (Lnx) 5 (1) The standard and sample were computed for 8000 s to collect spectral data to improve counting and assessment. The activity concentrations of 238 U, 232 Th, and 40 K, as well as the background in an empty beaker under the same conditions, were estimated after normalizing for background and heterogeneity [19].…”

“…Radionuclides from the 238 U and 232 Th family, as well as 40 K, are terrestrial primordial radionuclides that formed in the earth's crust and are natural sources of radioactivity in the environment [3].…”

Hydrogeochemical characteristics and terrestrial radiation of geothermal spring attractions in Central and Western Thailand

“…Besides, hazards of high background radiation levels in the geothermal attractions must be considered. Most of the reports of different geothermal locations around the world have focused on workers and frequent travelers in geothermal spring areas who are not only exposed to low radiation doses and longterm background radiation but also not aware of any negative effects [11][12][13]. For example, Ramsar in Iran, Guarapari in Brazil, Kerala in India, Yangjiang in China, and parts of the Flinders Ranges in South Australia are locations with these high background levels [11,13].…”

“…In particular, gamma radiation is a form of high-frequency ionizing radiation. Gamma rays are mainly produced by radium (Ra-226), as this natural radionuclide is one of the primordial radioactive elements in the Earth's crust [11][12][13].…”