Crash and Diesel Spill
A tractor pulling a 10000 litre bowser of diesel crashed on the bend of a main road and destroyed the earthen bank it crashed into. Oil from the bowser was lost to the road, its surface water drains, and nearby allotment land. The spill was in a protection zone of a major chalk aquifer. Emergency works were undertaken by the local authority to pump diesel from the drains and replace 1800 m2 of severely oil damaged tarmac.
Site surveys were undertaken to assess the extent of the contamination. Eye witness accounts were collated to identify spill events. Intrusive investigations identified that residual contamination around the drains was minimal, but that there were significant concentrations of diesel remaining in the soils of the allotment and adjacent to the road. Regular well monitoring was undertaken to check and report to the Environment Agency the condition of groundwater in the underlying aquifer.
Risks and Remediation
To reduce the risks to allotment users and controlled waters to acceptable levels, the removal and disposal to licensed landfill of 10 tonnes of oil contaminated soils near the spill source was proposed, followed by application of an oxygen releasing compound to reduce residual contamination in deeper soils. The remediation and reinstatement work was conducted successfully over a one week period, working under approved traffic management, and minimising traffic disruption at peak times. The earth bank destroyed by the crash was rebuilt, reinforced, and planted.
Validation was undertaken utilising field monitoring and submission of soil samples for analysis to a UKAS accredited laboratory and using Soil Guidance Values for residential land use with plant uptake.Back