Sickerwassertransport von Kolloiden und Schwermetallen in Bergbaufolgelandschaften - Felduntersuchungen und Laborversuche

The influence of colloids on the transport of heavy metals at a former lignite mining site was investigated. A three-dimensional hydrochemical mapping allows a view into the disposal revealing the stratigraphy within the water body. A SEM/EDX based single-particle method for the characterization of aquatic colloids was developed. Within a size range from 30 nm to 1 μm mostly inorganic silica and salt colloids were detected, whereas the size fraction below 30 nm was predominated by organic colloids. Although some heavy metals, mainly Co and Cu, were associated to colloids, the total amount of heavy metal colloids was neglectable. Silica colloids were chosen for batch and column investigations. Though the sorption coefficients suggested that the colloids should be a sink for heavy metals, no significant changes of the transport behaviour due to the presence of colloids was observed. Instead, the colloids were filtered by the sediment. The results of the field and laboratory work indicate clearly that there is no significant enhancement of heavy metal transport at the Kanena landfill site by inorganic colloids.