In March 2005 Gateshead Council determined that Dewhurst Terrace (as marked on attached plans and as situated within the Council's area), was contaminated land for the purposes of section 78A(2) of the Act because:
The Council had identified a source (contaminant), a pathway and a receptor with respect to the current use of the land and was satisfied that this pollutant linkage presented a significant possibility of significant harm being caused to that receptor.
Hydrocarbon contamination from leaking former underground fuel storage tanks (now removed) at the former fuel filling station which migrated under the A692 to the footpath and certain properties of Dewhurst Terrace.
Soil, made ground, service conduits and groundwater.
Human beings living and working in the properties, through inhalation of indoor vapours, and property in the form of buildings.
Remediation and Validation
Remedial works were undertaken in 2006-2008. The underground fuel storage tanks and hydrocarbon contaminated soils were removed from the garage forecourt area to remove the source of the contamination.
A network of ‘high vacuum extraction’ (HVE) and air sparging wells were installed both in the footpath of Dewhurst Terrace, connected into trenches which extended part way into the A692, and in the footpath on the garage side of the A692, to facilitate reduction of hydrocarbons in groundwater and hydrocarbon vapours in soil to predetermined target levels.
Floor slab removal and excavation of impacted soils under No 6 Dewhurst Terrace was undertaken followed by slab reinstatement including the installation of a hydrocarbon vapour resistant membrane.
The 2010 Remediation Consultant completion report concluded that the ‘site specific’ remediation target levels had been achieved and that the ‘significant risk of significant harm’ (SPOSH) to the Dewhurst Terrace receptors had been removed.
The conclusion was verified by an independent Remediation Validation Consultant following ‘post remediation monitoring works’ commissioned by the Council undertaken over a 2 year period (2012- 2014)
Extent of 2005 determination and subsequent remediation works.
Groundwater treatment and vapour extraction well system plan.