Contamination Risk Assessment

Residential Development –  Nuneaton

JPP Geotechnical and Environmental Ltd were appointed to undertake a detailed Phase I and Phase II geotechnical and geoenvironmental assessment at a former factory site which was recently demolished to floor slab level. It is proposed to redevelop the former industrial site into a new care home development.

Our Phase I desk study assessment identified that the site had been occupied by a historic works building for nearly 100 years and was considered to have a moderate to high risk of encountering residual on site contamination which could impact upon the redevelopment of the site.

Following a detailed review of the historical maps and the production of a site-specific risk assessment of the potential sources of both on site and off-site contamination, JPP scoped a detailed site investigation to target the identified risks.

Our ground investigation comprised the excavation of trial pits across the site to assess ground conditions in regard to both geotechnical design parameters and potential to encounter on site sources of contamination. In addition, a series of windowless sampler boreholes were drilled across the site to target potential sources of onsite contamination identified in the conceptual model and to allow for the installation of land gas and groundwater monitoring wells.

Following completion of the intrusive investigation works a range of both soil samples and groundwater samples taken from across the site were tested for a wide range of contamination associated with the sites historical land use which included heavy metals, metalloids, PAHs, petroleum hydrocarbons, VOCs and asbestos.

During our post fieldwork monitoring visits, groundwater samples were collected for contamination testing and land gas monitoring was undertaken to ascertain the site-specific gas screening value for the site to help determine to need for any land gas precautionary measures in the new development.

Our detailed assessment of the site in a staged manner enabled the ground investigation works to be undertaken in a phased approach, allowing the key risks associated with the sites historical usage to be identified at an early stage. The subsequent ground investigation works were therefore targeted at known risks enabling a more cost and time effective investigation of the site, helping to reduce the risks to our client whilst delivering the work within the required timescales and budget.

The ground investigation identified low levels of contamination which were addressed through the production of a Remediation Method Statement, enabling the identified hotspots of contamination to be addressed during the construction phase of the project. JPP managed the submission of the Remediation Method Statement to the Local Authority and secured discharge of the associated planning condition on behalf of our client.