Subcellular distribution of Cd and Pb in earthworm Eisenia fetida as affected by Ca2+ ions and Cd–Pb interaction

A semi-static solution culture method was used to study the effects of Ca2+ supply and interaction of Cd–Pb on the subcellular distribution of Cd and Pb in earthworm Eisenia fetida. The subcellular distribution of Cd and Pb was shown to be metal specific. About 80% of the Cd was distributed in the cytosol (fraction G), and only about 20% of total Cd was found in the tissue and cell membrane (fraction E) and the microsomes (fraction F). Nearly 50% of the Pb was rich in the tissue and cell membrane (fraction E). The supply of Ca2+ ions significantly decreased Cd concentration in the cytosol (fraction G) and the whole tissue of the E. fetida. At the subcellular level, the addition of Pb2+ ions significantly decreased the Cd percentage associated with fraction G from 83.7% to 58.4% and increased fraction E from 10.7% to 34.0%, respectively.