Total Indicative Dose Determination in Water from the North Riviera Well Field of SODECI in Abidjan, Cote d’Ivoire

The Uranium-238 (238U), Thorium-232 (232Th) families and Potassium-40 (40K) are of terrestrial origin and contribute generally to an individual’s external exposure through our presence in this environment. They also contribute to the internal exposure through the ingestion of products and beverages such as water that are close to the earth. The aim of this work is to determine the committed effective dose or Total Indicative Dose (TID) due to gamma radioactivity of the borehole water from the Nord Riviera (NR) well field operated by the Côte d’Ivoire Water Distribution Company (SODECI) for the supply of drinking water to part of the population of Abidjan. In addition, the populations, with their habits, could use these borehole waters directly as drinking water. To this end, water samples from the seven (07) functional boreholes were collected and analyzed on a gamma spectrometry chain, equipped with an HPGe detector in the laboratory of the Radiation Protection Institute (RPI) of the GHANA Atomic Energy Commission (GAEC). The results of the specific activities of 238U, 232Th and 40K obtained were transcribed into TID. As the natural radioactivity of the borehole water is high [1], the TIDs calculated from the activity results of the natural radionuclides238U, 232Th, and 40K vary for the seven boreholes from 0.150 to 0.166 mSv/yr with an average of 0.161 ± 0.034 mSv/yr. The TID of the control tower, where the borehole water is mixed and treated for household use, is equal to 0.136 ± 0.03 mSv/yr. The TIDs obtained are therefore all slightly greater than the WHO reference dose value of 0.1 mSv/yr. But all remain below the UNSCEAR reference dose of 0.29 mSv/yr.

Assessment of Radioactivity in Borehole Waters of the North Riviera Sodeci Catchment Field in Abidjan, Côte d’Ivoire

The radioactive isotopes of the decay series of uranium-238 (238U), thorium-232 (232Th) and potassium-40 (40K) occur naturally in varying amounts in groundwater. They are the subject of many measures, mainly because of the risk they represent from a public health point of view. The purpose of this study is to measure the radioisotope content of borehole waters from the north riviera (NR) catchment field of the Ivorian drinking water distribution company (SODECI). These measurements will make it possible to assess the absolute levels of radioisotopes in the water from SODECI’s boreholes used directly for drinking or swimming, and possibly the associated risk from a public health point of view. To achieve this, a sampling campaign from the seven functional boreholes and the control or treatment tower took place in July 2018 at the NR well field. The analysis of radionuclides by gamma spectrometry was carried out in the laboratory of the Radiation Protection Institute (RPI) of the Ghana Atomic Energy Commission (GAEC). The naturally occurring radionuclides identified during the borehole water samples analysis are 238U, 232Th, and 40K. The results reveal that the specific activities of uranium vary from 0.45 ± 0.18 Bq/L to 0.55 ± 0.17 Bq/L with an average of 0.49 ± 0.15 Bq/L. Those of thorium vary from 0.66 ± 0.14 Bq/L to 0.78 ± 0.18 Bq/L with an average of 0.72 ± 0.16 Bq/L and potassium of 4.14 ± 0.53 Bq/L at 5.87 ± 0.60 Bq/L with an average of 5.32 ± 0.58 Bq/L.