Radiostrontium in Some Vegetable Samples

As a part of national survey of radioactivity level in the environment the Radiation Protection Unit of the Institute for Medical Research and Occupational Health in Zagreb has been regularly monitoring the presence of radioactivity in the environmental samples. These investigations include determination of radionuclides mainly in natural samples such as air, fallout, geographic and drinking waters, soil, and especially in human and animal food samples. Radiostrontium, 90Sr, belongs to the group of very radiotoxic nuclides, and as such is very dangerous for human health. It is a bone seeker, and its short-lived daughter, yttrium (90Y), which soon reaches equilibrium, emits hard beta particles. Therefore, 90Sr is regularly determined in various kinds of natural samples from which it can directly or indirectly enter the human organism. To estimate the impact of 90Sr on the radioactive contamination of the Croatian environment, as well as internal radiation doses to the Croatian population, the investigations in this paper were focused on human foodstuff. The samples (potato, cabbage, lettuce and dry bean) were collected in different parts of Croatia (Zagreb, Zadar and Osijek), through last five years. Concerning exposure from intake of radionuclides, the limit to members of the public is 1 mSv per year. In our study all the estimated doses are far below this value - yearly effective dose levels and, therefore, current risk for the population of Croatia associated with 90Sr ingestion of vegetables can be considered negligible.(author)