Activity Concentrations and Gamma Dose rate Levels in Poultry Feeds and Manure used in Ibadan, Nigeria
Workers and dealers in poultry feeds, and commercial farmers may be exposed to elevated gamma radiation doses via internal and external exposure during handling of feeds and manure in farming operations. The measurement and evaluation of internal and external exposure to gamma radiation doses due to the distribution of activity concentrations of 40K, 226Ra and232Th in starter/grower poultry feeds, finisher poultry feeds and resulting poultry manure is therefore necessary from the radiation protection point of view. The measurement was done using Sodium Iodide activated with Thallium 𝑵𝑵𝑵𝑵𝑵𝑵(𝑻𝑻𝑻𝑻) gamma–ray spectrometer. The mean activity concentrations of 40K, 226Ra and232Th in finisher poultry manure were 382.33±67.12 𝑩𝑩𝑩𝑩 𝒌𝒌𝒌𝒌 −𝟏𝟏, 8.92±3.48 𝑩𝑩𝑩𝑩 𝒌𝒌𝒌𝒌 −𝟏𝟏, 39.20±5.58 𝑩𝑩𝑩𝑩 𝒌𝒌𝒌𝒌 −𝟏𝟏 respectively, and in finisher poultry feeds were 284.31±27.46 𝑩𝑩𝑩𝑩 𝒌𝒌𝒌𝒌 −𝟏𝟏, 15.21±8.88 𝑩𝑩𝑩𝑩 𝒌𝒌𝒌𝒌 −𝟏𝟏, 38.43±4.08 𝑩𝑩𝑩𝑩 𝒌𝒌𝒌𝒌 −𝟏𝟏. The distribution of 226Ra was more heterogeneous in all the samples than homogeneous distributions obtained in 40K and 232Th. The significant radiation exposure pathway to the farmers is from internal exposure due to inhalation of poultry and manure dust particles. The mean annual effective dose of 3.62±0.23 𝝁𝝁𝝁𝝁𝝁𝝁 𝒚𝒚−𝟏𝟏, 3.73±0.38 𝝁𝝁𝝁𝝁𝝁𝝁 𝒚𝒚−𝟏𝟏, 2.25±0.23 𝝁𝝁𝝁𝝁𝝁𝝁 𝒚𝒚−𝟏𝟏 were obtained for starter/grower feeds, finisher feeds, and finisher poultry manure respectively. The total annual effective dose calculated from the three major pathways for finisher poultry manure (2.94±0.48 𝝁𝝁𝝁𝝁𝝁𝝁 𝒚𝒚−𝟏𝟏) were lower than the results obtained for starter/grower (4.70±0.37 𝝁𝝁𝝁𝝁𝝁𝝁 𝒚𝒚−𝟏𝟏) and fin
