Historical disposal of Chromium ore processing residue (COPR) by the long-closed Whites Chemical Works in this part of south Glasgow has led to contamination of soil and groundwater by hexavalent chromium (Cr VI). However, the whole area is now part of an ambitious regeneration programme, part of which will see this large, vacant brownfield site transformed into a new business district. Other sites in the area have already been remediated by the developer Clyde Gateway. Before this site can progress to the remediation phase, the level of COPR contamination and its distribution across the site first needed to be thoroughly investigated.

The site was split into a number of packages of site investigation works and included drilling over 80 boreholes to a depth of ~50m below ground through bands of made ground containing COPR, thick seams of alluvium, glacial till and Carboniferous sedimentary bedrock. Rota-sonic drilling was proposed by ERS to minimise ground disturbance and mitigate a range of ground-related risks, including exposure of operatives to contaminants and further contamination to the wider environment. This also allowed for rapid advancement of the boreholes, and rotary core follow-on was possible with a simple switch of tooling. 

Additional techniques employed during the ground investigation included: 

• CPTu to gather detailed in-situ geotechnical and hydrogeological soil parameters.

• Trial pits and trenches to identify relict building foundations and structures.

• Down hole geophysics to map bedrock discontinuities. 

• Hydrogeological testing comprising packer tests and variable head permeability tests.

• On site PID and pH  testing 

• Installation of monitoring standpipes including continuous multi-channel tubing (CMT) piezometers for discrete multi-level water sampling.

• Post field works gas and groundwater monitoring and sampling 

• Geochemical and geotechnical laboratory testing, including geotechnical testing of heavily contaminated soils under Red lab protocol

ERS’ site team successfully completed the ground investigation works under persistent BDA Red site conditions, required to mitigate further soil and groundwater contamination via the works. The selected investigation techniques meant the quantity of drilling derived waste brought to the surface was kept to an absolute minimum, facilitating safe handling and reducing volumes of potentially hazardous waste from reaching landfill. Additionally, a special site setup was implemented with separate 'clean' and 'dirty' areas, and personnel and equipment wash down areas, to avoid cross-contamination. Dust monitoring equipment was also employed to ensure the risk to communities surrounding the site was minimised.

This extensive scope of works was carried out on schedule and well within budget, demonstrating a great deal of efficiency in delivering a complex contaminated land investigation.