Abstract
Investigation is made of 23 commercially available tourmaline-based healthcare products containing naturally occurring radioactive material (the products including hot spa stones, face masks, waist supporter slimming belts, arm relief belts, socks, insoles, soaps, and combs) with negative ion health benefits claimed by the purveyors. Assessment is made of the radiological risk posed by the use of such products, external exposure dose being the particular focus. Gamma spectroscopy analysis and Geant4 Monte Carlo (GMC) simulations are used. Organ doses are obtained using male and female human phantoms, dose conversion factors (DCFs) being included. For U-238 and Th-232t the tourmaline sock, code T20 was found to contain the greatest activity, at 2.4 +/- 0.2 and 28.0 +/- 1.3 Bq g(-1) respectively; least was for the magnetic therapy face mask, code T02, at respective values 0.04 +/- 0.01 and 0.1 +/- 0.01 Bq g(-1). Across all of the tourmaline products, the K-4 range was 0.16 +/- 0.01-16.4 +/- 1.1 Bq g(-1). In terms of elemental concentration, sample T20 offered the greatest concentration, with mean percentages of 0.022 +/- 0.001 and 0.78 +/- 0.10, for Th and U, respectively. With the assumption of exposure for a period of 8 h per day, wearing the tourmaline sock product T20 would give rise to an annual effective dose of 0.64 mSv, less than the public annual dose limit of 1 mSv. Noting that the samples may give rise to greater doses, national screening programmes for activity are suggested in seeking to mitigate unnecessary radiation exposure.