Laboratory experiment on the determination of radiostrontium transfer parameter in water – fish compartment system

Abstract

A laboratory experiment was conducted to investigate the water – fish transfer parameter of radiostrontium that potentially contaminate human body through water – fish – human pathway in the nuclear accident cases. In this experiment, carp fish (Cyprinus carpio), generally produced and consumed by Indonesian people, were cultured in a tank filled with 500 L water contaminated with 85Sr for two months. The observation of fish growth and radioactivity were conducted every five days by taking up three fish and water samples. The fish were dissected and separated into muscle, bones and internally organ, then destructed using chloric acid. The fish and water samples were then measured using gamma spectrometer with HPGe detector. The transfer parameter of transfer factor (Tf), uptake rate constant (u), elimination rate constant (k), and the effective half life (Te) were analyzed by mathematical equations. The high 85Sr concentration was observed in the bone by the Tf value of 67.99 ± 9.68 mL g−1 wet weight, whereas the concentration in muscle and internal organ were lower with the Tf of 26.05 ± 4.44 mL g−1 wet weight and 16.95 ± 2.34 mL g−1 wet weight, respectively. The values of u obtained from the mathematical calculation were 0.025 day−1, 0.029 day−1, and 0.04 day−1 for bone, muscle, and internal organ, respectively. Those values were higher compared to the k values, i.e. 0.018 day−1, 0.025 day−1, and 0.022 day−1 indicating the accumulation were take place in bone, muscle, and internal organ. The effective half life, which is the sum of physical and biological half life, of 85Sr in carp was about 30 days. The transfer parameter values determined from this experiment can be used in internal radiation doses assessment through water – fish – human pathways in case of radiostrontium contamination in freshwater environment, so a recommendation can be considered relating to the fish consumption during or after radiostrontium release to the environment.