Radioactivity of plutonium isotopes, 137Cs and their ratio in sediment, seawater and biota from the east coast of Peninsular Malaysia

Abstract

This study with sampling expeditions of marine sediment, seawater and biota were performed at 30 stations within Malaysian Exclusive Economic Zone (EEZ). A total of >400 samples were collected to determine the activity concentration of anthropogenic radionuclides (239+240Pu, 137Cs) and their activity ratio (239+240Pu/137Cs) in sediments, seawater and biota. The purpose of this study was to determine the concentration levels for these radionuclides and to evaluate any occurrence of radioactive contamination. Sediment cores were obtained using multicorer device, while water samples via co-precipitation techniques and biota was purchased from local fishermen. The activity concentrations of 239+240Pu in sediment, seawater and biota were ranged 0.21–0.45 Bq/kg dry wt., 2.33–7.95 mBq/m3 and <0.008 Bq/kg fresh wt., respectively. Meanwhile, the values of 137Cs were ranged <1.00–2.71 Bq/kg dry wt. in sediment, 3.40–5.89 Bq/m3 in seawater and <0.05–0.41 Bq/kg fresh wt. in biota, respectively. Activity ratios of 239+240Pu to 137Cs obtained seem to confirm that these artificial radioactivities were mainly due to global nuclear fallout.