DETERMINATION OF THE ACTIVITY CONCENTRATIONS OF RADIONUCLIDES AND THE ASSOCIATED HAZARDS OF SAND SAMPLES USED FOR BUILDING CONSTRUCTION IN SELECTED LOCAL GOVERNMENT AREAS IN AKWA-IBOM STATE, NIGERIA

Abstract

Sand which is used as a building material often emits radiation both outdoors [to the surrounding environment] and indoors [to the building residents]—whose doses may or may not be hazardous. In this study, the Radionuclide Activity Concentrations of ^40kK, ²³⁸U and ²³²Th in sixteen(16) Sand samples used for constructing buildings that were randomly collected from eight(8) rivers and eight (8) burrow-pits in six (6) Local Government Areas (LGAs) of Akwa-Ibom State, Nigeria; were determined by carrying-out a Gamma spectrometry using a NaI (Tl) detector. Also, the Radiological Hazard Assessment of the sixteen (16) Sand samples which involves indices such as Absorbed dose Rate (D), Hazard indices (external, H_ex and internal, H_in), Radium equivalent (Ra_eq), Annual effective dose rate (AEDR) (outdoor and indoor), Representative level index (I_y) and Total absorbed dose rate (D_4π) of the Sand samples were obtained through established Models (Equations) and Comparative analysis. Based on the results obtained, the following could be seen:  the average activity concentration ranges of ⁴⁰K were 91.86 ± 6.58 Bq.kg-1 to 167.64±11.99 Bq.kg-1  for Essien Udim, 61.72 ± 4.43 to 172.90 ± 7.37 Bq.kg-1 for Ikot Ekpene, 115.01 ± 8.25 for Ikono; the average activity concentration ranges of ²³⁸U were 5.70 ± 1.27 to 61.11 ±12.99 Bq.kg^-1 for Essien Udim, 13.19 ± 3.09 to 14.71 ± 3.01 Bq.kg^-1 for Ikot Ekpene, 10.80 ± 2.46 Bq.kg^-1 for Ikono;  and the average activity concentration ranges of ²³²Th were 2.68 ± 0.26 to 6.14 ± 0.60 Bq.kg^-1  for Essien Udim, 3.26 ± 0.32 to 4.34 ± 0.42 Bq.kg^-1for Ikot Ekpene, 4.36 ± 0.43 Bq.kg^-1 for Ikono; amongst others. Also, the mean values of Absorbed dose Rate (D), Hazard indices (external, H_ex and internal, H_in), Radium equivalent (Ra_eq), Annual effective dose rate (AEDR) (outdoor and indoor), Representative level index (I_y) and Total absorbed dose rate (D_4π) were: 18.799 nGy.h^-1, (0.107, 0.173) Bq.kg^-1, 39.508 Bq.kg^-1, (0.023, 0.092) mSv.y^-1, 0.283 Bq.kg^-1and 13.622 (10^-8 Gy.h^-1) respectively, amongst others. The above values indicate that both Absorbed dose radiation and Radiation hazard index are considerably low, thus implying that the Sand samples are good (safe) for building construction.