Effect of weathering transformations of coal combustion residuals on trace elements mobility in view of the environmental safety and sustainability of their disposal and use. II. Element release.

Abstract This paper is the second one of two companion papers. It presents results of a study aimed at assessing the effect of real time weathering transformations of Coal Combustion Residuals (CCRs) on trace element binding/release and its environmental implications. The study is based on the chemical composition of pore solutions extracted from primary alkaline Class F CCRs, 0 to >40 years old, sampled from the surface layer and vertical profiles at four selected typical CCRs impoundments. The long-term weathering transformations were found to lead to gradual acidification to pH   8), Dissolution II (8 ≥ pH ≥ 7) and Delayed Release III (pH