TITLE:
Assessment of Radiation Hazard from External and Internal Exposures at Adham and Surroundings in KSA
AUTHORS:
Emad Mayudh Al Thobaiti, Sadek Zeghib, Maher M. T. Qutub
KEYWORDS:
Radiation Hazard, Cancer Risk, Radon Exposure, Environmental Radioactivity, Gamma Spectrometry
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.11 No.6,
June
19,
2023
ABSTRACT: Twenty-eight environmental samples (eight well water, sixteen granitic rocks and
four soils) were collected from different parts of Adham governorate (Adham,
Haqal and Al-Jaizah), to assess the radiological hazard and cancer risk from
different perspectives. Adham is situated in a valley between two granitic
mountain chains, where much of water supply for drinking, house use and
irrigation comes from wells collecting water rains. The activity concentrations
of naturally occurring 40K, 226Ra and 232Th
and radionuclides were measured by gamma-ray spectrometry for all samples using
RGK-1, RGU-1 and RGTh-1, IAEA reference standards issued by the International
Atomic Energy Agency, for detector efficiency calibration. The measured values
were utilized to evaluate the internal and external exposures both outdoors and
indoors. Different standard room models were adopted for this respect to
evaluate the indoor gamma-rays exposure from construction materials as well as
internal exposure to radon gas emanating from them. Radon concentration
indoors, exceeded the upper reference level in dwellings set at 300 Bq/m3 by the world health organization, in many scenarios. The mean value of the
total excess lifetime cancer risk (due to external exposure from gamma-rays)
was 2.29 × 10-3, above the world average value of 1.45 × 10-3.
Furthermore, the measured radon concentrations in all water samples exceeded
the EPA (Environmental Protection Agency) 11.1 Bq·L-1 standard for
drinking water, ranging from 12 to 38 Bq·L-1 with a mean value of 27
Bq·L-1. The total annual effective dose (due to inhalation and
ingestion) from radon in water, ranged from 58 to 192 μSv/y (for adults) exceeding the international permissible limit of 100 μSv/y, in seven out of eight samples. According to obtained results, the
internal exposure from radon in directly used water from wells, might be the major
reason of any suspected radiological health hazard especially in Haqal. The
second reason might be the internal exposure from indoor radon gas inhalation
in poorly ventilated dwellings.