Bioaccumulation and distribution of Cesium-137 in the Humpback Grouper Fish (Cromileptes altivelis)

Humpback grouper fish (Cromileptes altivelis) is a highly valuable export commodity of food products. The high demand of this species needs to be supported by the intensive coastal aquaculture. However, the coastal aquaculture has been jeopardized by several threats, for an example radionuclide pollutant 137Cesium (137Cs) generated from nuclear reactor wastes. The pollutant accumulation in fish occurs because of continuing exposure to the pollutant-containing medium. This research was conducted from May to June 2015 at the Laboratory of Oceanic Radioecology, Center for Technology of Radiation Safety and Meteorology, National Nuclear Energy Agency, South Jakarta. This research observed the level of bioaccumulation and distribution of 137Cs in C. altivelis bodies. Radionucleid 137Cs of 2 Bq/mL concentration was inducted to two groups of fish, i.e. medium size (average body mass of 65.8 g ) and small size (average body mass of 34.7 g ). The calculation of concentration factor values at steady state (CFss) was done to determine the level of bioaccumulation 137Cs in fish body. The distribution of 137Cs in fish body was analyzed by calculating the percentage of accumulation 137Cs in a certain organ to the total accumulation in fish body. The results showed that the value of CFss of medium size fish was 1.23 and CFss for small fish was 2.01. It means that small size fish accumulated 137Cs almost twice as much as larger fish. The accumulation of 137Cs in C. Altivelis was found most in its muscle (meat), which was 63.34%. This research findings provide reason for us to be more careful in consuming humpback grouper fish coming from 137Cs polluted water due to the impact of biomagnifications of 137Cs in fish.