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Chemical Fractionation of Cadmium, Copper, Nickel, and Zinc in Contaminated Soils
Author(s) -
Ma Lena Q.,
Rao Gade N.
Publication year - 1997
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1997.00472425002600010036x
Subject(s) - bioavailability , cadmium , environmental chemistry , zinc , chemistry , soil water , fractionation , extraction (chemistry) , carbonate , metal , solubility , copper , soil contamination , nickel , geology , chromatography , soil science , bioinformatics , organic chemistry , biology
Heavy metals are potentially toxic to human life and the environment. Metal toxicity depends on chemical associations in soils. For this reason, determining the chemical form of a metal in soils is important to evaluate its mobility and bioavailability. Sequential extraction was used to fractionate four heavy metals (Cd, Cu, Ni, and Zn) from nine contaminated soils into six operationally defined groups: water soluble, exchangeable, carbonate, Fe‐Mn oxide, organic, and residual. The residual fraction was the most abundant pool for all four metals examined. A significant amount (2.4–44%) of Zn was present in the potentially available fraction: nonresidual fraction. A major portion (40–74%) of Cu was associated with the organic, Fe‐Mn oxide, and carbonate fractions in most of the soils. Contamination of Cd and Ni in these soils was not as severe as Zn and Cu. Assuming that mobility and bioavailability of these metals are related to their solubility and geochemical forms, and that they decrease in the order of extraction sequence, the apparent mobility and potential bioavailability for these four metals in the soils were: Zn > Cu > Cd > Ni. Metal distributions in different chemical fractions in these soils depended on respective total metal concentrations, except for Zn.