Transfer of radionuclides and stable elements to foodstuffs in Mediterranean ecosystems

Adequate radiological protection requires the quantification of radionuclide transfer to the human food chain, which is essential for the estimation of ingestion doses. Transfer parameters are key inputs for the development of radioecological models and decision support systems. There are many literature compilations of these parameters, however, most of values were calculated in temperate climates, and data for Mediterranean ecosystems are scarce. In this study, transfer factors to foodstuffs collected in Mediterranean ecosystems, in Spain, were compared to reported values for temperate climate. Foodstuff included cereals, meat (beef, lamb and pork), dairy products (milk, cheese yogurt, and kefir), and also typical products of Mediterranean diet, such as olives, olive oil, grapes and wine. Radioactive (137Cs, 226,228Ra and 40 K) and stable elements (Cs, Sr, K, Na, Ca, Mg, P, Pb, U and Th) were measured to enable the calculation of transfer factors. As a consequence, data for transfer factors in Mediterranean systems were increased by about 120 and 200 values for plant and animal products, respectively. Due to the low level radiocaesium concentration in Spanish ecosystems, transfer factors for this radioisotope were largely ‘less than’ values. Therefore, stable Cs and Sr transfer factors were used as proxy for comparison with temperate values.