EDTA Extractability of Trace Metals in Polluted Soils: A Chemical-Physical Study

• Published in: Environmental technology Vol. 19; no. 4; pp. 409 - 416
• Main Authors: Ghestem, J. P., Bermond, A.
• Format: Journal Article
• Language: English
• Published: London Taylor & Francis Group 01.04.1998; Selper
• Subjects: Applied sciences; Decontamination. Miscellaneous; Earth sciences; Earth, ocean, space; EDTA; Engineering and environment geology. Geothermics; Exact sciences and technology; polluted soils; Pollution; Pollution, environment geology; Soil and sediments pollution; trace metals; Cadmium; Sandy soil; EDTA; pH effects; Soil pollution; Clay loam soil; Zinc; Heavy metal; Trace element; Loamy soil; Decontamination; Complexing agent; Concentration effect; Lead; Kinetics; Copper; Performance; Chemical reactivity
• ISSN: 0959-3330; 1479-487X
• DOI: 10.1080/09593331908616696

The reactivity of a few trace metals (Cd, Pb, Zn, Cu) present in three polluted soils was studied using a classical extractant: EDTA. The effects of the concentration of this reagent (from 0.0001 M to 0.05 M) as well as those of the pH of the extracting solution (from 2 to 8) on the extracted amounts of metals have been determined. The behaviour of the cations seems to depend heavily on an excess or a lack of EDTA. In the case of an excess, concentrations of cations extracted are most of time pH-independent. On the contrary, when using a lack of EDTA, amounts of extracted cations show a complex behaviour versus pH which changes with the type of cation and with the degree of soil pollution. A competition phenomenon between minor and major cations of the soil seems to be revealed. These major cations seem to be Fe 3+ in acidic media and Ca 2+ in neutral media. However, when in excess, this reagent reveals a powerful extractant of trace metals in soils: recovery rates greater than 60 % have often been observed.