UPTAKE OF CS-134 FROM A SANDY SOIL BY 2 EARTHWORM SPECIES - THE EFFECTS OF TEMPERATURE

The uptake of Cs-134 by the earthworm species Lumbricus rubellus and E isenia andrei was studied in potted soils at different temperatures. C oncentration factors were between 0.23 and 0.37 for E. andrei, and bet ween 0.30 and 0.41 for L. rubellus. Biological half-lives ranged from 3 to 11 days for E. andrei and from 3 to 9 days for L. rubellus. The C s-134 uptake increased with temperature in both species. A 10 degrees C rise in temperature resulted in a 1.6-fold increase in Cs-134 concen tration in E. andrei and a 2.1-fold increase in L. rubellus. Maximum d ifference between Cs-134 concentrations of the two species was 2.4. Th e increase in internal Cs-134 concentration with increasing temperatur e could be mainly explained by earthworm-related factors such as incre ased metabolism or feeding rate since Cs-134 concentrations in solutio n did not increase with temperature in pots without earthworms. Cs-134 concentrations in soil solution from pots with earthworms compared to those in pots without earthworms were increased. Other soil solution characteristics, such as potassium, calcium concentration and conducti vity, were also affected by adding earthworms. The Cs-134 accumulation in earthworms was calculated as a function of the Cs-134 concentratio n in the soil solution over time. The results indicate, at least in th e case of L. rubellus, that since the accumulation pattern could not b e explained by concentrations in soil solution, uptake through food mu st contribute considerably to the total uptake.