Contaminated Land Case Study

A client was developing a former factory works in Tameside including the erection of multiple industrial units. The land had a history of industrial use and historical maps showed the presence of a former clay pit and an in-filled canal basin.

A condition of the planning permission required a contamination assessment whilst building regulations required a gas membrane to be incorporated within the footprint of all the units.

Pearl Environmental were commissioned to discharge the condition and investigate the gas regime on site. A desk study was undertaken which led to an intrusive investigation being designed to target the areas of interest. A window sampling rig was used to sample soils and logs were prepared characterise the soil profile.

Laboratory analysis suggested isolated contamination and drilling logs showed the presence of an anoxic degradable layer with organic odours. Gas standpipes were installed in each borehole and a programme of gas monitoring was undertaken during periods of varying atmospheric pressure events to include flow data. This enabled a risk assessment to be developed, the conclusions of which enabled the units to be constructed without the need for a gas membrane, saving the client many tens of thousands of pounds.