Modelling of Radiological Health Risk in Water from Abstraction Well Close to a Hypothetical Radioactive Waste Repository in the Accra Plains

Abstract

This study evaluated the integrity of the geosphere of the Accra Plains to host a radioactive waste disposal facility for Ghana’s radioactive waste materials. The study thus assessed the migration of radioactive contaminant from a hypothetical radioactive waste disposal facility through the geosphere to the biosphere in the Accra Plains. The Accra Plains is predominantly underlain by schist rocks, hence the hydrogeologic parameters of schist rock from literature were used as input data. AMBER software was used to develop a model to estimate the peak total annual effective dose from all the radionuclides at various receptor locations. The endpoint of interest was the dose received by a receptor for ingesting water from an abstraction well located at distance; 100 m, 200 m, 500 m, 1 km, 2 km, 3 km, 4 km and 5 km from the hypothetical repository. From the simulation, the annual effective dose values ranged from 2.07E-25 Sv/y to 6.45E-17 Sv/y which are all below the International Commission on Radiological Protection (ICRP) dose constraint of 0.3 mSv/y. The lifetime cancer risk for ingesting water from the abstraction wells were then calculated from the annual effective dose values. The resulting values ranged from 1.06E-24 to 3.30E-16 thus indicating that the potential cancer risk for ingesting water from the abstraction wells located within 100 m to 5 km from the hypothetical disposal facility is negligible. The model results demonstrate that, siting a disposal facility in the study area might not pose any significant risk to the sprawling population and the environment.