Uptake of Cs-134 from a sandy soil by two earthworm species: The effects of temperature

The uptake of Cs-134 by the earthworm species Lumbricus rubellus and Eisenia andrei was studied in potted soils at different temperatures. Concentration factors were between 0.23 and 0.37 for E. andrei, and between 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 Cs-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 concentration in E. andrei and a 2.1-fold increase in L. rubellus. Maximum difference between Cs-134 concentrations of the two species was 2.4. The increase in internal Cs-134 concentration with increasing temperature could be mainly explained by earthworm-related factors such as increased metabolism or feeding rate since Cs-134 concentrations in solution 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 conductivity, were also affected by adding earthworms. The Cs-134 accumulation in earthworms was calculated as a function of the Cs-134 concentration in the soil solution over time. The results indicate, at least in the case of L. rubellus, that since the accumulation pattern could not be explained by concentrations in soil solution, uptake through food must contribute considerably to the total uptake.