Investigation and Remediation of a site for Residential Development, UK

Abricon were commissioned to carry out an investigation into the site located in Lympne in Kent to enable planning conditions relating to contamination to be discharged.

The development was located on land that had been formerly used as a forge and as a public house.  A previous site investigation had been carried by a third which flagged up the presence of heavy metals and polynuclear aromatic hydrocarbons (PAH). The report concluded that all soils should be removed from the site to a depth of 1m and disposed of at a suitable facility - which would have been prohibitively expensive.

Abricon reviewed the site investigation report, and concluded that this result was mainly due to inadequate sample distribution. Abricon then took a number of samples from across the site at varying depths, using window sampling techniques, to assess both the horizontal and vertical distribution of contaminants. The sampling density enabled a more accurate assessment of contaminant distribution to be made. This in turn enabled a risk assessment to be carried out showing that contaminants were not uniformly distributed across the site but instead were present in hotspots where the Generic Assessment Criteria guideline values were exceeded.

Following sampling, analysis and risk assessment Abricon devised a remedial strategy in agreement with the local planning authority which would enable soil that had been excavated from the contamination hotspots to be reused under raised areas of hardstanding. Following testing to ensure hotspot removal, topsoil was bought in and placed in areas where elevated contaminant levels remained to ensure that human health risks were ameliorated.

The remediation carried out on the site enabled the local authority to discharge the planning conditions imposed on the site.

As a consequence of the remediation strategy the client was able to develop the site without having to remove contaminated soil from the site.

This provided a considerable costs saving in comparison to disposal at a licence waste facility.