Radioactivity and elemental concentrations of natural and commercial salt

Abstract Salt (NaCl) has importance not only in regard to the seasoning and preservation of food but also in greater mass utilisation settings, including the salting of roads in wintery conditions. The assessment of health benefits and risk from the intake of salt is of paramount importance, well appreciated in regard to hypernatremia and hypertension but much less considered within the content of natural radioactivity and heavy metals contamination. Present study examines the elemental and radionuclide concentrations of commonly used artificial salts in Malaysia, including Himalayan salt, table salt and Dead Sea cooking salt along with the natural Jordan Dead Sea salt, employing the techniques of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and High Purity Germanium (HPGe) gamma-ray spectrometry. Measured data have been compared with international advisory limits, as provided by the World Health Organization (WHO) and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Individual health risk assessment has been couched in terms of committed effective dose per year from the radionuclides 238U, 232Th, 40K, resulting from the consumption of the various salt inputs. This has led to an upper estimate for terrestrial radionuclide exposure radiation dose to individuals of some 17.1 μSvy−1, with an average of 4.3 μSvy−1, the latter some 70 times lower compared to the UNSCEAR reference annual advisory dose limit of 290 μSv (corresponding to the typical allowable limit for public exposures of 1 mSvy−1), representing negligible risk. With respect to heavy metals, the estimated daily intake (EDI) due to the consumption of salts shows the investigated salt samples to all be within the tolerable daily intake (TDI) as guided by the WHO, thereby posing inappreciable toxicity to human health.