A former firing range required remediation as part of a larger development.
The range had operated since early last century and the initial investigation had found soil lead values of up to 25g/kg. Most of the lead had degraded and solubilised into the soil matrix. Therefore, washing techniques to remove ordnance would not have worked, and bulk excavation for disposal would have been cost-prohibitive.
A process of detailed delineation showed the distribution of lead could be tightly defined to small hotspots within the range area. Field XRF was evaluated as a method of evaluation, however single analyte analysis at an accredited laboratory was chosen as the testing method due to its low cost, simplicity and ability to produce an accredited result.
The delineation was undertaken in ‘layers’ on a 4m sampling grid. Each layer being removed and segregated into low, medium and high impact materials.
The result identified a large proportion of the soil to be within re-use criteria for ‘commercial industrial’ end-use and could be re-used on the wider development under an existing MMP managed by the client’s Engineers.
The most highly impacted material was reduced to less than 25% of the overall volume of the soil in the range for very little additional processing cost over a bulk excavation method.