Naturally occurring radioactive material in groundwater: potential health risk to the inhabitants at Osino in the eastern region of Ghana

Drinking water from deep wells and boreholes is anticipated to have high concentrations of natural radioactivity from the decay of uranium, thorium, and potassium-40 isotopes. Ingestion of water containing radioactive matter for the long term dispenses potential health risks. This study sought to assess radiological quality in groundwater from selected boreholes used for domestic purposes in Osino, Ghana.

The analysis was done using gamma-ray spectrometry to determine the activity of radionuclides 226Ra, 228Ra and 40K in fifteen water samples collected from five selected boreholes. The samples were prepared into 1 litre Marinelli beaker, firmly closed and stored for 30 days to attain secular equilibrium between the long-lived radionuclides and their short-lived offspring.

The mean activity concentrations for 226Ra, 228Ra and 40K were 5.34 BqL-1±1.1 BqL-1, 9.21 BqL-1±2.0 BqL-1, and 35.64 BqL-1±5.6 BqL-1 respectively. The estimated radiological risks for cancer mortality and morbidity for 226Ra and 228Ra in the drinking water samples were below the WHO set screening level of 10-3. The mean hazard quotient estimated for 226Ra was 9.7 µgkg-1day-1. The total annual committed effective dose ranged from 5.27 x 10-2 mSvy-1 to 8.25 x 10-2 mSvy-1 with a mean of 6.87 x 10-2 mSvy-1 which was within the WHO set guidance level of 0.1 mSvy-1.

The radiological quality of the water is within the individual dose criterion and may not pose a health risk. It is paramount to monitor the radiological quality of the groundwater to provide relevant information to protect public health.