We carried out a site investigation, human health risk assessment, and controlled waters risk assessment at a former foundry and dyeworks situated near Manchester. An area containing elevated arsenic contamination was identified for remediation. Validation data collected after the completion of the remedial works demonstrated that the site was fit for residential redevelopment, and the brownfield site was subsequently redeveloped.
In early 2003 ESI, now part of Stantec, was commissioned to conduct a human health risk assessment for a former manufacturing plant occupying approximately 2.2 hectares and located around 13 km south-west of the centre of Manchester. The site was used for the manufacture of water and solvent-based inks. Operations ceased in 2002 and the intention was to redevelop the site for residential use.
Some previous site investigation work had been carried out in order to determine the nature and extent of any potential contamination. These investigations had found that the site was subject to contamination by heavy metals and petroleum hydrocarbons. We were commissioned by the client to undertake additional site investigations and to assess the potential risk to human health from the concentrations of contaminants detected in the ground.
A review of the available data relating to the site was undertaken, including the site’s history, geology, hydrology and hydrogeology, and the previous investigations of site contamination. A site visit to verify the site conditions was also carried out.
Conceptual site and exposure models were developed based upon the detected contaminant sources, and the potential contaminant transport pathways and receptors of concern for the proposed future land use. Risk assessments for controlled water and human health linkages were then undertaken.
Contaminant concentrations were demonstrated to pose no significant risk to controlled water receptors. Only arsenic exceeded the site-specific assessment criteria derived for the site. The area containing elevated arsenic contamination was identified for remediation by excavation and replacement with clean fill. Validation data collected after the completion of the remedial works demonstrated that the site was fit for residential redevelopment.
Our site investigation, risk assessment and remediation validation allowed the maximum land value to be realised at the site.