Speciation of metals in the fine fracion of solid waste from an excavated landfill

Abstract

In this current study, speciation of metals in the fine fraction (<10 mm) of excavated solid waste from an Estonian landfill was performed in order to evaluate metal contents and their potential mobility and bioavailability. The fine fraction speciation was carried out following the BCR sequential extraction method for Pb, Cu and Cd and the exchangeable (F1), reducible (F2), oxidizable (F3) and residual (F4) fractions were determined. The results have shown that Pb was highly associated with the reducible (F2) and oxidizable (F3) fractions suggesting the potential mobility of such metal mainly when in contact with oxygen, despite the low association with the exchangeable fraction (F1). The metal Cu has shown also potential for mobility and bioavailabilty when in contact with oxygen since high associations with the oxidizable fraction (F3). On the other hand, Cd was mostly found associated with the residual fraction (F4) were observed raising low concerns regarding mobility and toxic effects in case of excavation. To conclude, studies addressed to understand not only the total concentration of metals in solid phase, but also the speciation and which form metals are bound, are very important in order to bring information on how to manage fine fraction from excavated waste both in terms of environmental impacts and also recovery/extraction.