A Cyclic Approach for the Qunatification and Remediation of Subsurface Contamination

A new approach to contaminated land assessment and revitalisation, focusing on groundwater quality and complex contamination patterns at urban industrial megasites was developed. The new approach comprises three cycles: (a) the assessment of groundwater contamination using an integral mass flux based investigation method at the scale of entire industrial sites, (b) the delimiting of potential contamination source zones using backtracking and contaminant fingerprinting techniques, and (c) the development of emission oriented remediation strategies. The major advantage of the new approach is that the number of areas to be considered for further investigation and remediation is reduced from one cycle to the next. Consequently, a large potentially contaminated area is screened initially, but only a small area may be finally remediated, yielding a significant reduction of costs. The results from the integral investigation at the scale of entire megasites can be used for risk assessment purposes, for the quantification of the natural attenuation potential, as well as for the development of priorities for clean-up and / or further investigations and for the design of remediation measures. In addition, a consistent quantification of uncertainties in the results from the application of the integral groundwater investigation method is possible. Finally, the delimiting of the source zone extent and its uncertainty allows to define priorities for further investigation measures at a smaller scale, and to develop cost-optimized clean-up strategies. In this contribution, the focus will be on the three cycles of the new approach. Also, examples of application will be presented.