RESUMO
Activity concentrations of [40]K, [226]Ra and [228]Ra were measured in some sachet drinking water samples produced in Nigeria. The measurement was done by using high-purity germanium [HPGe] detector [Canberra Industries Inc.]. The measured activity concentrations for [226]Ra [U-series] and [228]Ra [Thseries] were used with their ingested dose conversion factors to estimate annual effective doses for the International Commission on Radiological Protection [ICRP] age groups 0-1y, 1-2y, 2-7y, 7-12y, 12-17y and >17y from consumption of the water samples. Measured activity concentration values varied from 0.57 +/- 0.21 to 34.08 +/- 5.61 Bq l[-1], 2.22 +/- 0.97 to 15.50 +/- 4.51 Bq l[-1] and 0.04 +/- 0.01 to 7.04 +/- 1.16 Bq l[-1] for the radionuclides respectively. Estimated total annual effective doses varied from 4.73 to 49.13, 1.21 to 12.26, 0.86 to 8.54, 1.22 to 11.66, 3.40 to 28.98 and 0.68 to 5.04 mSv y[-1] for the age groups respectively. The highest total annual effective dose was found in Tisco sample while the lowest was found in Focar sample. The total annual effective dose in all samples considerably exceeded the average worldwide ingestion exposure dose value of 0.12 mSv y[-1] from uranium and thorium series reported by the United Nations Scientific Committee on Effects of Atomic Radiations [UNSCEAR]. Therefore the Nigeria populace is advised to consume less of these water samples