Pakistan Journal of Geology (PJG)

Journal: Pakistan Journal of Geology (PJG)
Author: Andrew Sunday Oji, Odunyemi Anthony Ademeso, Sunday Olabisi Daramola, Kehinde Ibrahim Adebayo

This is an open access journal distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

DOI: 10.26480/pjg.02.2025.80.88

The study assessed heavy metal concentration and radiological hazards in selected basement rocks from Igarra, used in construction. Twenty rock samples were collected from two quarry sites (Calc-silicate-gneiss and Lamprophyre), Ten (five from each) were then carefully picked and analyzed for natural radioactivity and heavy metal concentrations using X-ray Fluorescence spectrometry (XRF). Standard conversion factors were applied to convert radioactive metals into activity concentrations of radionuclides, and radiological hazard indices were calculated. The mean heavy metal concentrations followed the order: Fe > Cr > Zn > Ni > Pb > Cu > Co > Th > Sn > Ra > As > Cd and Fe>Cr>Zn>Pb>Ni>Cu>Th>Co>Sn>Ra>As>Cd for calc-silicate-gneiss and lamprophyre respectively. The average activity concentrations of 226Ra, 232Th, and 40K varied between 19.34-74.65 Bq/kg, 28.18-195.29 Bq/kg, and 970.3-2115.88 Bq/kg respectively. Lamprophyre had higher activity concentrations and radiological indices, including radium equivalent activity, external and internal hazard indices, gamma representative index, absorbed dose rates, annual effective dose equivalents and excess lifetime cancer risk, compared to Calc-silicate-gneiss. Although both rock types exhibited activity concentrations, gamma indices, and absorbed dose rates and excess lifetime cancer risk (outdoor) above the world average, radium equivalent activity, external and internal hazard indices, annual effective doses and excess lifetime cancer risks (indoor) were within safe levels. The study concludes that while the radiological impact is tolerable, quarry workers might face higher exposure due to elevated outdoor radiation levels. Additionally, some trace metals exceeded Earth’s crust averages, presenting potential toxicity risks if inhaled or ingested. While the rocks are deemed safe for construction, their use in interior decoration is not recommended to avoid potential long-term radiation exposure indoors.