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

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

doi:10.3390/app11125412

Abstract

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.

Highlights

Humans are continually exposed to ionizing radiation, most pointedly from the natural radionuclides within terrestrial media
In Malaysia, the country in which present study was conducted, a recent health fad concerns online undergarment products markets, and the present study addresses the naturally occurring radioactive material (NORM) content of these so-called negative ion garments
Across the same category of undergarments, considerable differences in radioactivity content could be observed, an example being the variation of 238 U series of between 2 ± 0.5 and 175 ± 26, while for the 232 Th series it was between 15 ± 2 and 1732 ± 247; for 40 K it was between 29 ± 5 and 207 ± 38

Summary

Introduction

Humans are continually exposed to ionizing radiation, most pointedly from the natural radionuclides within terrestrial media. The ubiquitous nature of naturally occurring radioactive material (NORM) is well understood, with a presence in soil, water, and air. While exposure to ionizing radiation emitted by 238 U, 232 Th, and. 40 K can constitute a risk to the living environment [2,3], the low doses from most natural environments do not typically give cause for concern. Certain anthropogenic activities can increase radioactivity concentration levels, with elevated doses sometime well beyond those of the natural background [4]. For individuals who are exposed at these levels, NORM contributions may cause cancer [5]. From the viewpoint of radiation protection, the monitoring of natural radioactivity in human surroundings is of primary importance

Methods

Results

Conclusion