Radiological safety assessment of mined Trona commonly consumed in Nigeria

ABSTRACT

Mined Trona is a naturally occurring inorganic salt that is consumed by humans for diverse purposes in Nigeria. Due to the increase in consumption rates of these salts following a renewed government interest in solid minerals exploration and exploitation, it is imperative to assay its radiological content. Reconnaissance survey revealed that the most commonly used Trona varieties were: Farar Kanwa, Jan Kanwa, Dan Libya, Ngurnu, Manda, Farar Balma, Jar Balma and Yar Agadez. Samples of the identified Trona varieties were purchased from markets within Zaria, Nigeria. The samples were analysed using NaI (Tl) gamma ray spectrometry system. Radium equivalent activity (Ra_eq), annual effective dose (AED), Internal and Alpha hazard Indices (H_in and I_α) and total cancer risks (TCR) were used to assess the radiological safety of its consumption. The activity concentration of ²³⁸U (²²⁶Ra); ²³²Th and ⁴⁰K varied widely and had an average ± error values of 42.904 ± 4.54 Bq/kg, 11.96 ± 1.41 Bq/kg and 455.28 ± 10.56 Bq/kg respectively. Ra_eq, AED, I_α, H_in and TCR were estimated at 95.07 ± 63.10 Bq/kg, 68.52 ± 52.53µSv/y, 0.21 ± 0.23, 0.37 ± 0.27 and (390.57 ± 299.44) ×${10}^{-06}$respectively; which were by far less than the US EPA and UN SCEAR acceptable thresholds. It was established that the threshold consumption rate is 40 Kg/year and any value slightly higher than the threshold values will be associated with a significant radiological health risk. Therefore, at the present consumption rate of Trona in Nigeria, there is no cause for radiological concern.

KEYWORDS:

• Trona
• radioactivity
• radiological risk
• effective dose
• cancer risk

Disclosure statement

No potential conflict of interest was reported by the author(s).