Chemical fractionation of trace elements in an amphibolite soil amended with municipal solid waste composts
Résumé
An agricultural acid soil developed on amphibolites was amended with 5% of five commercial composts (produced mainly from municipal solid wastes) and incubated in the laboratory during 90 days, with the objective of studying the fate of trace elements in soil after compost addition by means of chemical analyses based on BCR fractionation schemes. In general, the addition of the composts had little effect on the distribution of trace elements, because of their high previous contents in the soil. Compost addition increased the oxidizable (organic matter) and reducible (iron oxides) fractions of soil Cu, and the soluble and reducible fractions of soil Zn. None of the composts modified Pb distribution, which was mostly found in the reducible fraction, nor that for Cr or Ni, present in more than 80% in the residual non-extractable fraction. Among the elements studied, Zn was that of most concern, since the addition of some composts increased the soluble forms of this element.