Redistribution of residual Pb, Zn, and Cd in soil remediated with EDTA leaching and exposed to earthworms (Eisenia fetida).
After soil remediation with ethylenediamine tetraacetate (EDTA) leaching/washing, the residual Pb, Zn, and Cd species are left in the soil in non-labile forms. The effect of earthworms as main soil biotic factors on the residual Pb, Zn, and Cd fraction lability (mobility, bioavailability to plants, and oral-availability) was investigated. Contaminated soil from a smelter site was treated with increasing EDTA concentrations (2.5 to 4-times 40 mmol kg(-1) to gradually reduce the heavy metal content and lability. Leached soils were processed by Eiseniafetida and heavy metal lability and fractionation determined in casts and earthworm-processed soils. In general E. fetida increased heavy metal accessibility/mobility, but the induced changes diminished with the intensity of soil EDTA treatment. Fractionation results indicate the possibility of a time-dependent complexation of heavy metals to carbonates favoured by earthworms' gut processes. The transition of residual heavy metals in time (ageing) should be considered.
Udovic
Metka
M
Agronomy Department, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia.
Lestan
Domen
D
D000042:Absorption; D000818:Animals; D001673:Biodegradation, Environmental; D002104:Cadmium / Q000302:isolation & purification / Q000493:pharmacokinetics; D004492:Edetic Acid / Q000737:chemistry*; D005374:Filtration / Q000379:methods; D007854:Lead / Q000302:isolation & purification / Q000493:pharmacokinetics; D019216:Metals, Heavy / Q000302:isolation & purification* / Q000493:pharmacokinetics*; D009835:Oligochaeta / Q000378:metabolism*; D012989:Soil Pollutants / Q000737:chemistry* / Q000493:pharmacokinetics*; D015032:Zinc / Q000302:isolation & purification / Q000493:pharmacokinetics
D019216:Metals, Heavy; D012989:Soil Pollutants; D002104:Cadmium; D007854:Lead; D004492:Edetic Acid; D015032:Zinc