Determination of natural radioactivity levels and gamma radiation attenuation coefficients in propolis samples and the study of its antioxidant properties

Thanks to its rich content, propolis has been used to protect the hive from all kinds of external influences and for disinfection by bees. Furthermore, it is an important marker for monitoring environmental pollution because the main sources of propolis are plant and secretions. So, the present study aimed to research radiation attenuation capability and the natural radioactivity level of propolis samples. For this reason, both natural radioactivity concentrations (Ra-226, Th-232 and K-40) and attenuation coefficients (Linear and Mass) in the propolis samples collected from 10 different points in Turkey were measured using high purity germanium detector (HPGe). The average natural radioactivity concentrations in samples were found to be 0.56 +/- 0.19, 2.65 +/- 0.31 and 70.08 +/- 2.42 Bq/kg for Ra-226, Th-232 and K-40, respectively. These values were much lower than the average world values (35 Bq/kg for Ra-226, 30 Bq/kg for Th-232 and 400 Bq/ kg for K-40) reported by United Nations Scientific Committee on Effects of Atomic Radiation (UNSCEAR) in foodstuff. The average linear attenuation coefficient, mass attenuation coefficients and half value layer values for gamma rays with 59.54 keV energy were determined as 0.1970 cm(-1), 0.1831 cm(2) g(-1) and 3.56 cm, respectively. In addition, antioxidant properties of the samples were measured using total phenolic content and ferric reducing antioxidant power. Their correlations with radioactivity were investigated.