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  • Author or Editor: D. H. Mu x
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Abstract  

Three kinds of marine bivalves (wild Saccostrea cucullata, aquacultured Perna viridis and aquacultured Pinctada martens), collected from Daya Bay, the South China Sea, were used to investigate the bio-accumulation of radioruthenium in the glass aquarium with natural seawater (pH 8.20, 35‰ salinity, filtered by 0.45 μm) at ambient temperature under laboratory feeding conditions. The experimental results show that the stead-state of biology concentration factor (BCF, ml/g) of radioruthenium was approached around 6 days for most species of bivalves. The values of BCF in shells are the highest in organs all the three bivalves. The orders of BCF values (ml·g−1) are as: Perna viridis (33.2) < Saccostrea cucullata (47.0) < Pinctada martensi (208.4) for shells and Saccostrea cucullata (1.5) < Pinctada martensi (2.2) ≈ Perma viridis (2.4) for soft tissues, respectively, after exposed for 14 days. The rate constants of uptake and elimination of radioruthenium on marine bivalves were also discussed by first-order kinetics model. The Pinctada martensi may be applicable to be an indicator for monitoring radioruthenium among the three bivalves.

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Abstract  

The sorption/desorption of radioruthenium was investigated by the batch method in sea water system at ambient temperature on the surface sediments obtained around the Daya Bay of Guangdong Province, where the first nuclear power station of China has been running from 1994. It was found that the sorption percentage was obtained to be around 40% for all the surface sediments in 60 minutes. Then, the sorption percentage goes up slowly. The sorption percentage of radioruthenium reached around 80% in 113 days (2713 hours). The distribution coefficients decreased from 3.16·104 to 1.35·103 ml/g with the increasing of sediment concentration in the range of 4–10000 mg/l. The results of the desorption experiments suggest that the sorption of radioruthenium is irreversible with 81.5% relative hysteresis coefficient.

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Summary  

The comprehension of the behavior of radioactive nuclides in aquifer requires the study of the sorption processes of nuclides in various geochemical conditions. The sorption/desorption of 65Zn(II) on surface sediments (0-2 cm) was investigated by batch method in sea water (pH 8.20, 35‰ salinity, filtered by 0.45mm) at ambient temperature. The surface sediments were obtained from four stations around the Daya Bay of Guangdong Province (China), where the first nuclear power station of China has been running from 1994. The sorption process is fast initially and around 39% average of sorption percentage (SP%) can be quickly obtained in 15 minutes for all the surface sediments. Then, the sorption percentage becomes constant. In 30 days of contact time 79.6% sorption percentage and K d=3.9. 103ml/g distribution coefficient was obtained. The value of K dbecame constant, 4.0. 103ml/g, in contact time more than 120 hours. The distribution coefficient K ddecreases with increasing sediment concentration from 4.0 to 250 mg/l from 1.31. 104to 1.68. 103ml/g, respectively. Then the value of K dgoes up to 5.38. 103ml/g with sediment concentration of 3000 mg/l. The desorption experiments suggest that the sorption of Zn(II) is irreversible with a hyteresis coefficient of 66%.

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