Radiological risk assessment of fish feed and feed raw materials

In this study, natural radioactivity concentrations of fish feed and feed raw materials were assessed. Several feeds and raw materials were provided from the suppliers who dominate the aquaculture sector. Ra-226, Th-232 and K-40 concentrations were determined by using a high-purity germanium detector. The measured activity concentrations of samples ranged from 3.28 +/- 0.27 to 15.90 +/- 1.36, from 1.27 +/- 0.10 to 12.07 +/- 1.21 and from 52.01 +/- 2.60 to 1,158.96 +/- 54.42 Bq/kg for Ra-226, Th-232 and K-40 respectively. The gamma dose rate and annual effective dose rate of samples were calculated to be in the range of 1.99-50.47 nGy/h and 2.44-61.89 mu Sv/yr respectively. Since the calculated radiological risk parameters of the samples were lower than the world wide average values, the radiation hazard is insignificant for human handlers.