Radiological Risk Assessment due to Ingestion of some Bottled Drinking Water on the Ghanaian Market

M O Portuphy,A Faanu,A Sawyerr

doi:10.4314/gjs.v59i1.8

Abstract

Activity concentrations of the Naturally Occurring Radioactive Materials (NORMs) in some bottled drinking water brands obtained from some supermarkets in Accra were analyzed using gamma spectrometry.40 K activity concentrations were in the range of 3.57 - 5.47 Bq/L, the highest occurring in brand L9. Similarly, 232 Th activity concentrations were in the range of 0.30 - 0.56 Bq/L with the highest occurring in brand L8. 226 Ra was identified in eleven brands with the remaining 5 below detection limit. The highest value (0.53 Bq/L) occurred in brand L9. Comparison of the mean concentrations showed significant differences at (α = 0.05) between the various brands of bottled water. Estimated committed effective doses were generally below 0.1 mSv/a for all age groups with the exception of children <1yr. Estimated lifetime cancer and hereditary risk were done using the ICRP risk assessment methodology.

Highlights

Natural radiation comes from cosmic rays, naturally-occurring radioactive elements in the earth’s crust, and radioactive decay products
40 K activity concentrations were in the range of 3.57 - 5.47 Bq/L, the highest occurring in brand L9
16 brands of bottled drinking water were analyzed for natural radioactivity using gamma spectrometry

Summary

Introduction

Natural radiation comes from cosmic rays, naturally-occurring radioactive elements in the earth’s crust, and radioactive decay products. Since these radionuclides are present in soil and rock, they can be found in groundwater and surface water. Natural radionuclides commonly found in waters include 238 U, 234 U, 232 Th, 226 Ra, 238 Ra, 222 Rn, 210 Pb and 40K (Dragani et al, 1990) The existence of these radionuclides normally occurs in wells dug deep into aquifers containing radionuclides of variable oxidation states. The concentration is not necessarily restricted to the surface geological characteristics. Even variable ground flow patterns may result in seasonal variations in radionuclide concentrations (Lieser et al, 1990)

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