Octolasion tyrtaeum
Octolasion tyrtaeum is an endogeic earthworm feeding dead roots, root exudates and decaying organic matter in shallow and even deeper soil layers prefering mineral and humus rich soil. (ref. ID; 6703)
[ref. ID; 6703]
Test system
The effect on heavy metal (Pb, Zn and Cd) fractionation of processing the soil through earthworm's digestive tracts, mobility, and oral-bioavailability in earthworms casts
Strains
Worms were collected manually during turning over in a non-polluted managed vegetable garden, were used fully clitellated adult specimens and subadult specimens with developing tubercula pubertatis.
Toxicants
Soil was collected from the upper 30 cm layer of a managed vegetable garden near the abandoned lead smelter in the Mezica Valley in Slovenia. Pb mining and smelting activity in the Mezica Valley ceased in 1990, after more than 300 years of uninterrupted activity.
Test design
Pot experiment: Clean plastic pots (height 9 cm, diameter 12.5 cm) were filled with 250 g of air-dried non-leached and leached soil, in three replicates. 80% of soil field water capacity. 10 earthworms (average 0.74 g fresh weight) introduced into each pot and kept in the dark at 20 degrees C for 4 weeks.
Lead bioavailability in warm casts was determined as oral bioavailability in simulated stomach (pH 2.50+/-0.05) and intestinal (pH 7.00+/-0.05) phases of human gastrointestinal tract, using Ruby's physiologically based extraction test.
Measurements/observations
The concentration of Pb, Zn, Cd and pH in O. tyrtaeum casts. Fractionation of Pb, Zn and Cd in worm casts.