Summary
The high expense of decontaminating polluted land frequently prevents brownfields from being put to use, thereby leading space being wasted.
The project’s aim was to develop a method for evaluation of contaminated spaces that differs from the BBodSchV. The approach here is to make bioavailability of pollutants, including their interrelations with the soil matrix, the primary evaluation criterion rather than the overall pollutant contents.
To this end, the potential harm of contaminated soils on four model pieces of land were evaluated by means of elution tests and subsequent ecotoxicological examinations. The results were used to infer statements on the risk to the groundwater and on the retention capacity. They were further compared with the results of the conventional procedure according to BBodSchV (which excludes bioavailability).
Results:
- The leachates’ PAH concentrations exceed the BBodSchV limit value. However, the pollutants displayed negative, ecotoxic impact neither in the fluorescent bacteria test nor in the algae test. Mobilisation was almost impossible to discern in the samples polluted with petroleum-derived hydrocarbons.
- All examinations based on bioavailability determine a significantly lower hazard potential than indicated by the total pollutant contents.
- The findings were collated into an action manual which lists the boundary conditions to be observed and explains how to conduct hazard potential estimation and pollution assessment in accordance with the integrated availability approach. A description of the required methods and evaluation concepts as well as the requirements to be met during sampling and quality assurance was drafted.
