Behaviour of metalloids and metals from highly polluted soil samples when mobilized by water – Evaluation of static versus dynamic leaching

The mobilization behaviour of metalloids and metals when leached by water from highly polluted soil/sediment samples was studied using static and dynamic approaches employing batch methodology and rotating coiled columns (RCC), respectively. Increasing the solution-to-solid ratios during batch leaching resulted in different enhanced mobilization rates, which are element-specific and matrix-specific. When dynamic leaching is employed with continuous replacement of the eluent, a higher portion is mobilized than when using batch elution with an identical solid-to-water ratio.Using RCC the time-resolved leaching of the elements was monitored to demonstrate the leaching patterns. For the majority of elements a significant decrease could be shown in the mobilized portion of the elements with ongoing leaching process. The data were discussed targeted at solid liquid partitioning coefficients of the metal(loid)s. The capabilities in application of Kd values was demonstrated for dynamic leaching which is relevant for environmental processes.

► We examine the mobilization of metal(loid)s by water under simulated conditions.
► Static versus dynamic leaching (RCC) with continuous supply of extractant was compared.
► RCC is favourable for detailed time-resolved investigations of the leaching behaviour.
► The influence of matrices on the leaching behaviour was investigated.
► The capabilities of the Kd values in environmentally relevant processes is shown.