Uptake and Transfer of Cesium‐137 by Chlamydomonas, Daphnia, and Bluegill Fingerlings
1964
King, Susan F.
Concentration factors of Cs—137 for Chlamydomonas moewusii, Daphnia pulex, D. magna, and Lepois macrochirus fingerlings were determined following direct exposure to the isotope in solution and following ingestion of labeled food by the daphnids and fish. Cesium specific activity, temperature, and algal cell concentration were varied to determine effects on Cs—137 uptake. of Cs—137 by all organisms was less at 8° than at 22°C. Chlamydomonas uptake rose with increase of available cesium in the water up to 1.0 ppm and fell with increasing algal densities. Cesium uptake bu D. pulex and D. magna differed. D. pulex uptake of Cs—137 increased but D. magna uptake was not affected when available labeled Chlamydomonas was increased. In direct uptake studies at 22°C, D. pulex concentrated three times the amount of Cs—137 concentrated by D. magna. Direct uptake of Cs—137 by L. macrochirus was negligible. Fingerlings showed increased uptake when allowed to feed for 24 hr on labeled daphnids. Efficiency of removal of Cs—137 from ingested food was 21% for D. pulex, 13—14% for L. macrochirus, and 0.0% for D. magna. In on food chain study at 22°C, Chlamydomonas, at 20 x 10⁷ cells/liter, reached a 24 hr concentration factor of 319; D. pulex, after feeding on the labeled alga for three days, had a concentration factor of 354; and the striated muscle tissue of L. macrochirus, which had fed for one day on the labeled D. pulex, had a concentration factor of 7.8. Rad dosages received by each species from Cs—137 decay in the water and organisms were calculated. Based on the concentration factors given in the above food chain study, Chlamydomonas received 0.11 rads/day, D. pulex 8.5 rads/day, and L. macrochirus muscle 0.38 rads/day.
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