The Annual Dose for Qena Governorate Population Due to Consume the Animal Products
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Proceedings of the 4 th Environmental Physics Conference, 10-14 March 2010, Hurghada, Egypt THE ANNUAL DOSE FOR QENA GOVERNORATE POPULATION DUE TO CONSUME THE ANIMAL PRODUCTS S. Harb, K. Salahel Din, A. Abbady and Nagwa Saad Physics Dept., Faculty of Science, South Valley University, 83523, Qena, Egypt Several kinds of cattle and poultry fodder samples collected from South Valley University and Qena governorate farm, Qena, Upper Egypt were estimated for their natural radioactivity concentrations due to Ra-226, Ra-228, Th-232 and K-40 radionuclides. Twenty nine samples were analyzed by using low-level gamma- spectrometric. Based on radionuclides concentrations in animal fodder and annual consumption rate, the human health risk from irradiation due to indirect ingestion can be assessed. The annual effective dose from these radionuclides, which may reach the local consumer through beef, milk, poultry and eggs consumption have been estimated as 2.7E+00, 1.4E+01, 1.0E-01 and 1.4E-01 µSv/y, respectively. Keyword s: Radioactivity , Natural radionuclides, Gamma spectrometric, Animal and poultry feed , Annual effective dose 1. INTRODUCTION Radiation from natural sources gives more than 80 % of the total exposure received by the average member of a population and a portion of this exposure comes from dietary intake [1]. The natural radioactivity elements are distributed everywhere in the environmental with different concentrations, their concentrations have been found to depend on the local geological condition and as such they vary from one place to another. It is necessary to monitor release of radioactivity into the environment in order to be able to provide an appropriate protection of humans [2]. Radionuclides in soil are taken up by plants, thereby becoming available for further redistribution within food chains these plants may be involved directly in human food or indirectly such as animal fodder [3]. Over the years much work on radioactive food contamination in the environment and its transfer or pathway mechanism to plants, animals and human population has been reported [4, 5]. Ingestion of natural radionuclides depends on the consumption rates of food and water and on the radionuclide concentrations. The supply of meat in Egypt comes from four major sources. These are cattle, poultry, goat meat and mutton. Cattle contribute the highest percentage of 44.54 % and poultry takes second place with 36.86 % while mutton contributes (sheep and goat) 3.8 % each [6]. The aim of this study is to calculate the doses received by population in Qena governorate owing to consume products from south valley university farm and -37- Proceedings of the 4 th Environmental Physics Conference, 10-14 March 2010, Hurghada, Egypt governorate farm. In order to accomplish this objective we measured the activity concentration levels due to naturally occurring radionuclides in animal's food and then using theoretical calculation to calculate the annual doses received by population in Qena governorate due to consume the animal products. 2- MATERIALS AND METHODS The animal and poultry fodder samples were collected from South Valley University (S.V.U.) and Qena Governorate (Q.G.) farms on Qena-Safaga road in Qena governorate figure 1. Fodder samples for each location were dried in air to obtain a constant dry weight. The samples were powdered and then transferred into cylindrical plastic containers. These samples were sealed and left for a period of one month to allow Ra and its short-lived progenies to reach secular radioactive equilibrium. Specific activity of each radionuclide was calculated using the following equation [7]: As = C n / ( ε P γ M s) (1) where, A s is the specific activity of each radionuclide in sample (Bq/kg), Cn is count per second, ε is the detector efficiency, Pγ is the emission probability, and M s is sample weight (kg). Figure 1. Qena governorate map. Each sample was measured with a NaI (Tl) detector, although the NaI (Tl) gamma-ray spectrometer has poor energy resolution but its high efficiency allows fast and precise determinations of Ra-226, Ra-228, Th-232 and K-40 concentrations in samples. The results depend on the accuracy of the energy calibration procedure that takes into account the possible interference of each nuclide in each peak region. In order to minimize the background radiation, the detection system and the sample container were placed inside a shield, composed by lead layer, with thickness of 5 cm. -38- Proceedings of the 4 th Environmental Physics Conference, 10-14 March 2010, Hurghada, Egypt Every sample was counted for 10 to 15 h depending on the level of concentrations of the radionuclides. System was calibrated for efficiency using a mixed ten radionuclides gamma standard QCY48 (obtained from Physikalisch Technische Bundesanstalt PTB, Germany) [8], before the sample was placed in detection system. Prior to sampling counting, background were normally taken every week under the same condition of sample measurement and then subtracted from the samples counted during that week. The spectra were evaluated with the computer software program Maestro (EG&GORTIC). Figure 2 show gamma lines which are measured by NaI. The Ra-226 concentration was determined from the gamma lines of 352 keV and 609 keV from Pb- 214 and Bi-214. Ra-226 concentration was calculated as the mean value of the results of these gamma lines. The Th-232 concentration was determined from the gamma lines of 238 keV, 911 keV from Pb-212 and Ac-228, respectively and Ra-228 was determined from the gamma line 911 KeV from Ac-228. K-40 was determined from its gamma lines of 1460 keV. 10000 Pb-212 214 - Pb-214 Bi Bi-214 Ac-228 K-40 Bi-214 1000 Tl-208 100 Log Count 10 1 0 500 1000 1500 2000 2500 3000 Energy (Kev) Figure 2. The gamma spectra of radionuclides from fodder samples (Rs). 3- RESULTS AND DISCUSSION Table 1 presents the result of the specific activities of R-226, Ra-228, Th-232 and K-40 in the different samples under investigations. Cattle fodder The average value of Ra-226, Ra-228, Th-232 and K-40 concentration in South Valley University farm fodder were 0.30 ± 0.01, 0.31± 0.02, 0.28 ± 0.02 and 83.52 ± 2.99 Bq/Kg, respectively, in Fodder mixture, while in grass fodder (Silage and Rice straw) -39- Proceedings of the 4 th Environmental Physics Conference, 10-14 March 2010, Hurghada, Egypt they ranged from 3.58 ± 0.17 to 4.31 ± 0.17, 2.63 ± 0.15 to 5.33 ± 0.23, 1.99 ± 0.13 to 2.51 ± 0.14 and 282.72 ± 10.13 to 397.12 ± 14.15 Bq/Kg, respectively. The mean values of these radionuclides in Qena Governorate farm fodder mixture were 1.62 ± 0.06, 1.85 ± 0.07, 0.23 ± 0.04 and 195.26 ± 6.36 Bq/Kg, respectively, while in grass fodder (Hay and Rice straw), they were 3.20 ± 0.15, 3.31 ± 0.22, 2.36 ± 0.17 and 377.02 ± 13.33 Bq/kg, respectively. The results showed that the average values of Qena Governorate farm were higher than South Valley University farm values. Table 1. Ra-226, Ra-228, Th-232 and K-40 activity concentrations (Bq/kg) in fodder samples from two farms. Activity concentration (Bq/Kg) (dry weight) Samples Farm Farm Ra-226 Ra-228 Th-232 K-40 Type feed Type feed Fodder mixture (FM) 0.30 ± 0.01 0.31 ± 0.02 0.28 ± 0.02 83.52 ± 2.99 Silage (Zea mays) (Sz) 3.58 ± 0.17 3.16 ± 0.18 1.99 ± 0.13 282.72 ± 10.13 Silage (Sorghum) (Ss) 4.31 ± 0.17 5.33 ± 0.23 2.17± 0.15 363.08 ± 12.31 Cattle’s food Cattle’s food Rice straw (Rs) 3.91 ± 0.17 2.63 ± 0.15 2.51± 0.14 397.12 ± 14.15 Poultry feed 1 (PF1) 0.35 ± 0.02 0.95 ± 0.05 0.27 ± 0.03 62.98 ± 2.25 S.V.U. farm S.V.U. farm food Poultry feed 2 (PF2) 0.38 ±0.02 0.49 ± 0.03 0.33 ± 0.02 60.51 ± 2.13 Poultry’s Fodder mixture (FM) 1.62±0.06 1.85±0.07 0.23±0.04 195.26±6.36 Hay (H) 2.46±0.11 2.82±0.24 1.87±0.17 292.95±10.51 food Cattle’s Rice straw (Rs) 3.93±0.19 3.79±0.20 2.85±0.16 461.09±16.15 Q.G. farm farm Q.G. Poultry feed 1 (PF1) 1.12±0.06 1.33±0.05 0.84±0.04 80.87±2.87 s foods 1.17±0.04 1.58±0.08 1.07±0.06 91.21±3.19 Poultry’ Poultry feed 2 (PF2) Poultry fodder In South Valley University farm, the mean values of Ra-226, Ra-228, Th-232 and K-40 activity concentrations were 0.35±0.02, 0.95±0.05, 0.27±0.03 and 62.98 ±2.25 Bq/kg, respectively for (Pf1), whereas corresponding values in (Pf2) were 0.38±0.02, 0.49±0.03, 0.33±0.02 and 60.51±2.13 Bq/kg. Whereas the mean values of these radionuclides in Qena Governorate farm are 1.12±0.06, 1.33±0.05, 0.84±0.04 and 80.87±2.87 (Bq/kg), respectively in Poultry feed1 and in Poultry feed2 are 1.17±0.04, 1.58±0.08, 1.07±0.06 and 91.21±3.19 (Bq/kg), respectively. From results the average values of these radionuclides in poultry fodder from Qena Governorate farm were higher than South Valley University farm values.