UPTAKE OF CESIUM-134 BY THE EARTHWORM SPECIES EISENIA-FOETIDA AND LUMBRICUS-RUBELLUS

The uptake processes of Cs-134 in two earthworm species were investiga ted as well as the effect of temperature on these processes. The resul ts show that equilibrium concentrations in the two species differ by 1 .5- to fivefold. Equilibrium concentrations range from 367 to 963 Bq g (-1) in Lumbricus rubellus and from 920 to 1,893 Bq g(-1) in Eisenia f oetida; biological half-lives range from 56 to 119 h and 52 to 64 h, r espectively. Assimilation was two to four times higher in E. foetida a nd elimination rate one to two times higher in E. foetida than in L. r ubellus. Further, the results show that temperature may affect the Cs- 134 concentration in these earthworms by a factor of 1.4 to 2.1 betwee n 10 and 20 degrees C, depending on the species. The maximum differenc e found within one species was a factor of 2.6. Our results show no cl ear effect of temperature on the assimilation, but a small negative ef fect on elimination, resulting in an increasing biological half-life a nd concentration factor with higher temperatures.