FOOD CONTAMINATION IN THE REGION OF VRANJE Lj. Javorina, G. Pantelic, I. Tanaskovic, M. Eremic-Savkovic, V. Vuletic, Institute of Occupational and Radiological Health "Dr Dragomir Karajovic", Belgrade, Yugoslavia Abstract. The locations evidently contaminated by depleted uranium ammunition in the region of Vranje have been identified and marked, while local population has been warned against the danger from contaminated soil and longer stay in that region. With a view to protect the health of population, the radioactivity measurements of the environment have been performed by methodology of vertical analysis of samples. During 2001 and 2002, the food sampling was carried out from the region of Vranje in the following locations: Pljackovica, Borovac, Reljan, Bukurovac, Balinovac and Bujanovac. In these locations, the food (rabbit, grapes, thyme, blackberry, pumpkin, tomato, paprika, dog-rose berry, chanterelle, mushroom, honey, cheese, corn) was sampled from the fenced areas demarcated by the Yugoslav Army as contaminated region as well as beyond fenced areas assumed not be contaminated. Food samples were dried at room temperature, fragmented and after preparation they were placed in cylindrical geometry. The samples of vegetation obtained from the international intercomparation were used for calibration. The results of gammaspectrometry of foodstuffs revealed low levels of natural radionuclides and 137Cs (as a result of Chernobyl accident) in all locations of Vranje region. The obtained values of 40K ranged from 30 Bq/kg to 297 Bq/kg, 235U from < 0.06 Bq/kg to < 0.70 Bq/kg, 238U from < 0.35 Bq/kg to 18 Bq/kg, 226Ra from < 0.20 Bq/kg to 3.8 Bq/kg, while 137Cs values ranged from < 0.09 Bq/kg to 3.0 Bq/kg. So far, depleted uranium has not been verified in any of these samples. Only after longer monitoring and testing of all environmental segments of this region, its imperilment and true health risk of population could be evaluated. 1.Introduction During NATO bombing of the region of Vranje in 1999, ammunition with depleted uranium was used. Locations proved to be contaminated with the depleted uranium were marked and enclosed by Yugoslav Army. Uranium in Serbia derives from naturalsources, considering the geological composition of rocks and geochemical composotion of soil, and their concentration as well as the concentrations of its descendants represents the significant component of natural sources of ionizing irradiation. In Serbia, the major uranium sources are igne ous, carbonic and sedimentaru rocks, and granite. According to perennial geological investigation of uranium in our country, several geological regions have been found to have uranium in higher or lower concentration. The uranium concentration in these regions ranged from 0.003 g/t for ultra basic rocks to 3.5 g/t for igneous, sedimentary rocks and granite [1]. The 238U and 235U specific activities and their isotopic composition correspond to depleted uranium (238U/235U ratio from 35 to77)[2]. Uranium migration potential depends on the chemical composition of the local soil and water as well as on the oxidation products of the depleted uranium (Rajković). [3]. When uranium comes into the organism via the food it may express both chemotoxicity and radiotoxicity. Local population was warned on the risks. For the purpose of populations’ health protection the method of vertical analysis of samples (water, air, crops, food, soil and precipitations) was applied for measurement of environmental radioactivity. The samples were collected in October 2001 and in September 2002. The sampling was performed by the Institute team either independently or assisted by the organized UNEP mission. Food samples were obtained both from the enclosed areas and out of such areas that were supposed not to be contaminated. The sampling was performed in the following locations within the region of Vranje: Pljačkovica, Borovac, Reljan, Bukurevac, Balinovac and Bujanovac[4]. 2.Methods All the food samples were initially cleansed from soil and other impurities to be subsequently prepared in usual manner. Each sample was dried at room temperature, crushed and homogenized. The samples were placed in cylindrical geometry. Calibration was performed using vegetation samples obtained by the international inter-comparison. Gammaspectrometric measurement was performed on pure germanium detector manufactured by EG&G "ORTEC" (with relative efficiency of 25% and energy resolution of 1.85 keV) connected to multi-channel analyzer (8192 channels) produced by the same manufacturer with appropriate computer equipment. Measurement interval of single sample is 60000s. Table I. Specific radionuclide activity in different food samples in region of Vranje in 2001 Sample Location 40K 232Th 238U 235U 226Ra 137Cs (Bq/kg) (Bq/kg) (Bq/kg) (Bq/kg) (Bq/kg) (Bq/kg) Honey Pljačkovica 17 ± 1 < 0.63 < 2.8 < 0.16 < 0.31 < 0.14 Cheese Pljačkovica 30 ± 1 < 0.15 < 1.7 < 0.06 < 0.61 0.08 ± 0.03 Cheese Pljačkovica 43 ± 2 0.3 ± 0.1 < 1.3 < 0.07 0.23 ± 0.09 < 0.09 Corn Borovac 56 ± 3 < 0.62 < 4.9 < 0.23 < 0.38 < 0.1 Cheese Borovac 43 ± 2 < 0.28 0.35 ± 0.09 < 0.09 0.20 ± 0.03 0.23 ± 0.05 Rose hip Reljan 236 ± 12 2.6 ± 0.3 18 ± 4 0.7 ± 0.3 < 1.7 < 0.8 Rose hip Bukurevac 186 ± 10 < 1.3 < 10 < 0.5 < 1.4 < 0.4 Corn Bukurevac 49 ± 3 < 0.8 < 3.4 < 0.4 < 0.5 < 0.3 Pumpkins Bukurevac 42 ± 2 < 0.4 < 3.4 <0.2 <0.4 <0.2 Rose hip 1 Borovac 297 ± 13 < 2.9 < 22 < 0.8 < 1.3 < 0.9 Rose hip 2 Borovac 176 ± 10 < 2.3 < 15 < 0.7 < 11 < 0.8 Table II. Specific radionuclide activity in different food samples in region of Vranje in 2002 40K 232Th 238U 235U 226Ra 137Cs Sample Location (Bq/kg) (Bq/kg) (Bq/kg) (Bq/kg) (Bq/kg) (Bq/kg) Rose hip Reljan 159 ± 6 3.0 ± 0.4 3.4 ± 0.9 < 0.3 3.8 ± 1.1 < 0.3 Chanterelle Bujanovac 178 ± 6 < 0.4 < 2.8 < 0.1 < 2.2 3.0 ± 0.1 Boletus 49 ± 2 < 0.3 < 2.2 < 0.1 < 1.7 2.5 ± 0.1 Bujanovac mushroom Rabbit Pljačkovica 87 ± 3 < 0.2 < 2.3 < 0.1 < 2.1 0.16 ± 0.05 Grapes Balinovac 34 ± 2 < 0.8 < 4.7 < 0.2 < 2.7 < 0.19 Thyme Borovac 115 ± 6 < 1.9 < 13 < 0.7 < 12 0.85 ± 0.30 Blackberry Borovac 43 ± 5 < 1.8 < 18 < 0.26 < 4.8 1.0 ± 0.4 Pumpkin Borovac 71 ± 2 < 0.11 < 0.73 < 0.12 < 0.50 0.16 ± 0.02 Tomato Borovac 70 ± 2 < 0.23 < 1 < 0.25 < 0.85 0.12 ± 0.04 Paprika Borovac 83 ± 3 < 0.28 < 2 < 0.23 < 1.2 < 0.068 3.Мeasurement results Gammaspectrometric measurements on food samples evidenced low values of natural radionuclides as well as 137Cs (as a consequence of Chernobyl accident) obtained from all locations in the region of Vranje. The obtained 40K values ranged between 30 Bq/kg to 297 Bq/kg, while 235U values ranged between < 0.06 Bq/kg to < 0.7 Bq/kg, and 238U values ranged between 0.35 Bq/kg and 18 Bq/kg. The activity ratio of 238U and 235U corresponds to the ratio in the natural uranium. 226Ra values ranged between 0.20 Bq/kg and 3.8 Bq/kg, while 137Cs values ranged between < 0.09 Bq/kg and 3.0 Bq/kg. 4.Discussion Gammaspectrometric measurements performed on these food samples revealed significantly low values of the natural radionuclides, as well as low 137Cs activity. Presence of the depleted uranium in food products has not been evidenced for the time being. Since penerators were found at these locations and soil that came in direct contact with projectiles was significantly contaminated, although depth and scope of the contamination cannot be determined precisely, only long-term monitoring and examination of all environmental segments of this location will enable evaluation of its endangerment and true risk for population. 5. Reference 1.G.Djuric, D.Popovic, Uranium in enviroment-″ground state″ in Serbia, Letters of Chemists and Technogists Association in Yugoslavia, Vol.55, Belgrade, 2001, 1-6 2.G.Pantelic, M.Eremic Savkovic, Lj.Javorina, I.Tanaskovic, V.Vuletic, S.Milacic, Gammaspectrometric determination of depleted uranium in Yugoslavoa, European IRPA Congress, Florence, Italy, 2002: N-084 3.Eremic Savkovic M, Pantelic G, Javorina Lj, Tanaskovic I, Vuletic V. Radioactivity Measurments of Soil Samples in the Republic of Serbia for the Period 1999-2001. European IRPA Congress, Florence, Italy, 2002: R-137 4. "Radioactivity environmental samples in Republic of Serbia", yearly reports, Clinical Center of Serbia-Institute for Occupational and Radiological Health " Dr Dragomir Karajovic", Belgrade, 1986-1999. .