Assessment of Radioactivity Concentration in Milk Samples Consumed in Italy

Abstract

Background and Objectives: Being highly consumed by the population for nutritional purposes, the monitoring of radionuclides in milk represents a very important task for the protection of human health. The present paper reports the results of an investigation aimed at determining the natural and anthropogenic radioactivity content in milk and assessing the radiological health risks due to its ingestion. Methods: Liquid for infants, Ultra Heat Treated (UHT) sheep, UHT cow, and UHT goat milk samples, coming from Italian large retailers, were investigated. In particular, a total of twenty samples, five for each type, were analyzed by using High Purity Germanium (HPGe) gamma-ray spectrometry, with the ultimate goal of quantifying the specific activity of natural and anthropic radionuclides (40K and 137Cs, respectively). The evaluation of dose levels due to the milk ingestion was also performed for six age categories, namely infants, 1-5, 5-10, 10-15, 15-17 years old, and adults (> 17 years old), taking into account the average yearly direct consumption in Italy and under the a priori hypothesis that this need can be satisfied by a single variety of milk. Results: The mean specific activity of 40K varies from (30 ± 4) Bq L-1 to (48 ± 6) Bq L-1; the lowest value was obtained for the UHT sheep milk, while the highest one for the UHT cow milk, with investigated Italian large retailers milk samples presenting an activity concentration of (38 ± 5) Bq L-1 on average. The 137Cs specific activity is lower than the minimum detectable activity (MDA) value for all investigated samples. Regarding the dose levels due to the milk ingestion, the obtained values remain below the threshold value of 1 mSv y-1 set by the Italian legislation. Conclusion: Reported results then show that the radiation dose incurred from the ingestion of the investigated milk samples poses no significant health effect on the population from a radiological point of view.