Measurement of radium isotope activities in reservoir and spring water in the Cameroon Central Region

Abstract

Purpose: To determine the activities of ²²⁶Ra and ²²⁸Ra in the reservoir and spring water samples respectively during the dry and the rainy seasons; and to calculate the annual intake Ii (Bq/y) for each type of water samples.

Methods: Using both well calibrated Canberra NaI(Tl) and HPGe detector systems, it was possible to determine the average specific activity of those radium’s isotopes in water samples which were collected in 2010, from Reservoirs and springs in Cameroon central region including Ngoaekelle, Minboman, Etoudi and Njoungolo.

Results: The average specific activity values obtained for ²²⁶Ra and ²²⁸Ra in reservoir water samples were 8.76 ± 3.50 BqL^-1 and 0.64 ± 0.28 BqL^-1 during the dry season and, 8.24 ±3.48 BqL^-1 and 0.58 ± 0.24 BqL^-1 during the rainy season respectively. For spring water, the average values were 3.50 ± 0.63 BqL^-1 and below 0.0002 BqL^-1 (detection limit of ²²⁸Ra in water) during the dry season; 3.20 ± 0.60 BqL^-1 and below 0.0002 BqL^-1 (detection limit of ²²⁸Ra in water) during the rainy season respectively. Assuming that the volume of drinking water for adult is 2.5 litres per day, the average annual intakes of ²²⁶Ra and ²²⁸Ra through ingestion in these water samples were 7702 Bq/y and 575 Bq/y for reservoir water; 2993 Bq/y and < 0.25 for spring water respectively.

Conclusion: The results have indicated that the annual intake by the population of sampling region as a result of ²²⁶Ra in these drinking waters is 7.7 × 10³Bq/y more than the maximum limit fixed by ICRP which is 7 × 10³ Bq/y. There is a need for regular monitoring the radiological water quality aspect in this region.