Applied Sciences (Jun 2021)

The Enhanced Naturally Occurring Radioactivity of Negative Ion Clothing and Attendant Risk

  • Halmat Jalal Hassan,
  • Suhairul Hashim,
  • Noor Zati Hani Abu Hanifah,
  • Muhammad Fahmi Rizal Abdul Hadi,
  • Mohamad Syazwan Mohd Sanusi,
  • David Andrew Bradley,
  • Rafael García Tenorio,
  • Rozman Mohd Tahar

DOI
https://doi.org/10.3390/app11125412
Journal volume & issue
Vol. 11, no. 12
p. 5412

Abstract

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The study investigates commercially available negative ion clothing, and evaluations are made using gamma-ray spectroscopy and Geant4 Monte Carlo simulations. Observed to contain naturally occurring radioactive material (NORM), evaluations are made of the radiological risk arising from the use of these as items of everyday wear, undergarments in particular. Organ doses from these were simulated using the MIRD5 mathematical female phantom, with the incorporation of dose conversion factors (DCFs). At 175 ± 26, 1732 ± 247, and 207 ± 38 Bq, for 238U, 232Th, and 40K respectively, item code S05 was found to possess the greatest activity, while item code S07 was shown to have the least activity, at 2 ± 0.5 and 15 ± 2 Bq, and again for 238U and 232Th, respectively. Sample code S11 recorded least activity, at 29 ± 5 Bq, for 40K. Among the clothing items, sample item code S05 offered the greatest concentrations of Th, U and Zr, with percentage means of 1.23 ± 0.1, 0.045 ± 0.001, and 1.29 ± 0.1, respectively, giving rise to an annual effective dose of 1.57 mSv/y assuming a nominal wearing period of 24 h per day. Accordingly, the annual public dose limit of 1 mSv can be exceeded by their use.

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