Measurement of Radioactivity in Common Powered Milk Consumed in Sana’a, Yemen and Estimation of the Associated Annual Effective Dose

Abstract

This study focuses on measuring the radioactivity in milk, given its critical importance and sensitivity as a fundamental component of humannutrition, particularly due to its vital role as a primary food source for children during the early stages of life. The radionuclides of ²³²Th, ²²⁶ Ra and ⁴⁰K were measured in 16 brands of powdered milk consumed in Yemen, imported from various regions worldwide. The measurements were conducted using gamma-ray spectroscopy with an HPGe detector, equipped with a specially designed shield. The range of  ²²⁶ Ra from (0.42±0.08 to 1.86±0.30 with an average of 0.77±0.12) Bq/kg, the range of ²³²Th from (0.21±0.05 to 0.40±0.07 with an average of 0.30±0.05) Bq/kg, and the range of ⁴⁰K (from 140.69±3.90 to 195.96±5.29 with an average of 169.06±4.63) Bq/kg, respectively, for infant group (≤ 1 year). The range of ²²⁶Ra from (0.14±0.03 to 7.21±1.34 with an average of 1.88±0.54) Bq/kg, the range of ²³²Th from (0.25±0.04 to 1.22±0.34 with an average of 0.68±0.15) Bq/kg, and the range of ⁴⁰K (from 141.52±3.90 to 534.39±13.54 with an average of 320.36±8.35) Bq/kg, respectively, for individuals above 2 years, respectively. The total average annual effective dose due to ingestion of radionuclides was calculated for three age groups and found to be (214.50, 123.27, and 41 μSv/year) for infant group (≤ 1 year), children (2-17 years), and adults (>17 years), respectively. Overall, these values are lower than the WHO/FAO and ICRP recommended limit of (1.0 mSv/year) for all age groups, indicating that the radioactivity levels in the tested powdered milk are within acceptable safety limits.