Abstract: Chemical speciation is a significant factor that governs the
toxicity and mobility of heavy metals in municipal solid waste incinerator fly
ash. Sequential extraction procedure is applied to fractionate heavy metals
(Pb, Zn, Cd, Cu, and Cr) into five defined groups: exchangeable, carbonate,
Fe-Mn oxide, organic, and residual fractions. The mobility of heavy metals is
also investigated with the aid of toxicity characteristic leaching procedure.
In the fly ash sample, Pb is primarily presented in the carbonate (51%) and
exchangeable (20%) fractions; Cd and Zn mainly exist as the exchangeable (83%
and 49% respectively); Cu is mostly contained in the last three fractions
(totally 87%); and Cr is mainly contained in the residual fraction (62%). Pb,
Zn and Cd showed the high mobility in the investigation, thus might be of risk
to the natural environment when municipal solid waste incinerator fly ash is
landfilled or reutilized.
Keywords: municipal solid waste incinerator fly ash, heavy metals, chemical speciation, mobility