Assessment of solid mineral to soil radioactivity contamination index in selected mining sites and their radiological risk indices to the public

ABSTRACT

This study examined the radioactivity levels of soil samples within selected solid mining sites in Nigeria using high-purity germanium (HpGe) detector. Sixty soil samples in all were collected from the 10 solid mineral mining sites investigated and six samples were collected as control samples from non-mining environment for analyses. The results of the activity concentration values obtained for ⁴⁰K, ²²⁶Ra and ²³²Th are 100.22 Bq kg⁻¹, 33.15 Bq kg⁻¹ and 77.31 Bq kg⁻¹, respectively. The ²²⁶Ra and ⁴⁰K activities were found to be within the United Nation Scientific Committee on the Effects of Atomic Radiation acceptable permissible limit, but the ²³²Th mean value was above the permissible limit of 30 Bq kg⁻¹ for the public. In comparison, ⁴⁰K, ²²⁶Ra and ²³²Th soil samples mean activity concentrations were higher than the control soil samples values by 48.6%, 43.7% and 62.3%, respectively. The results of estimated radiation hazard indices indicate average values of 150.72 Bq kg⁻¹, 68.40 nGyh⁻¹$\mathrm{n}Gy{h}^{-1}$, 83.65 µSvy⁻¹ and 454.70 µSvy⁻¹ for the Radium Equivalent (Ra_eq$\mathrm{R}{\mathrm{a}}_{\mathrm{e}\mathrm{q}}$), Absorbed Dose Rate (D), Dose Equivalent (AEDE) and Annual Gonadal Equivalent Dose (AGED), respectively. The mean values for External Hazard Indices (Hex, Hin), Representative Gamma index ($I_{\gamma }$) and Excess Life Cancer Risk (ELCR) were 0.41, 0.50, 1.06 and 0.29 × 10⁻³, respectively. The statistical analysis shows positive skewness.

KEYWORDS:

• Radioactivity
• mineral
• soil
• percentage contribution
• mining area

Acknowledgments

The authors wish to appreciate the assistance of the Federal Ministry of Solid Minerals for providing us the needed information, materials and access for the success of this investigation.

Ethical Approval

This paper abides by all ethical standard of the journal and contain no ethical issues whatsoever.

Consent to Participate

All authors consent was sorted and agreed before the research work commenced. All authors also consent to participate in the writing of this article and the submission of the final paper to this journal.

Consent to Publish

This is to certify that all authors consents were sorted and approval gotten to publish this paper in this Journal. We the authors declare that there is no conflict of interest among us in this research work.

Authors’ contributions

The research work was conceived by Dr. Agbalagba E.O and redesign for wider readability by Prof. Stephen O. Egarievwe, while Dr. Mohammed S. Chaanda did the geological identification and characterisation of sites and solid minerals in each site. All the three authors contributed mutually from the development and data analysis in this research work. Dr. Agbalagba E.O. did the writing which other authors vetted and agreed before sending for consideration in this Journal.

Disclosure of potential conflicts of interest

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

Availability of Data and Material

The datasets generated and/or analysed during the current study are not publicly available, but will be made available from the corresponding author on reasonable request.

Additional information

Funding

We the authors state that there is no funding of any kind from individual, cooperate bodies or government agencies in this research work.