Environmental assessment of radionuclide exposure in packaged borehole water exploited from crystalline rocks in Ogbomoso

Abstract The amounts of naturally occurring radionuclides ( 40 K, 238 U and 232 Th) in packaged borehole water manufacture have been investigated in this work. Furthermore, the buildup of radioactive materials in drinking water presents a direct path for human population exposure to internal radiation. The amount of radioactivity in the processed and unprocessed water samples was measured using gamma spectrometry and a computer-resident quantum multichannel analyser (MCA 2100R) connected to a well-calibrated and shielded NaI (Tl) detector. From the results, it was revealed that the values of activity concentration of processed water ranges between 50.46 ± 3.14 Bq/L to 102.18 ± 14.07 Bq/L, 7.92 ± 4.46 to 16.71 Bq/L, and 10.00 ± 0.84 Bq/L to 14.87 ± 4.03 Bq/L for 40 K, 238 U and 232 Th, respectively. Also, the results obtained for the activity concentration of unprocessed water ranges between 74.51 ± 3.51 Bq/L to 102.21 ± 7.23 Bq/L, 14.86 ± 1.91 Bq/L to 19.87 ± 3.10 Bq/L and 10.00 ± 3.36 Bq/L to 17.79 ± 4.43 Bq/L for 40 K, 238 U and 232 Th, respectively. The results confirmed the presence of 40 K as a principal occurring radionuclide in the water samples. The annual effective dose for processed water ranges from 0.012 to 0.017 mSyr −1 , while it ranges between 0.015 and 0.020 mSyr −1 for unprocessed water. Results in the present study fall below 0.1 mSyr −1 , which is the acceptable limit recommended by International Commission on Radiological Protection standard value.