Influence of soil properties on molybdenum uptake and elimination kinetics in the earthworm Eisenia andrei

This study aimed at determining the uptake and elimination kinetics of molybdenum in the earthworm Eisenia andrei, and the influence of soil properties on molybdenum bioaccumulation. Three natural and four artificial soils were spiked at concentrations of 10 and 100 μg Mo g−1 dry soil. Earthworms were exposed individually to spiked soils and sampled at different time intervals for 21 d. Remaining earthworms were transferred to non-spiked soil to determine elimination, also for 21 d. Uptake and elimination rate constants and bioaccumulation factors (BAFs) were calculated using a one-compartment model, and related to total, water and CaCl2 extractable molybdenum concentrations in soil. Molybdenum was rapidly accumulated by the earthworms with uptake rate constants between 0.05 and 1.70 g dry soil g−1 dry earthworm d−1, and equilibrium generally was reached within 10 d. Molybdenum was not strongly bioaccumulated (BAF ⩽ 4). Mo availability and bioaccumulation in earthworms was mainly affected by soil pH and organic carbon content.