Multiple Contamination Assessment and Consultancy Services at Holiday Park, Cornwall
A full range of contamination investigation and assessment services have been provided for a large and on-going holiday accommodation development in Cornwall.
The Phase 1 Contamination Assessment identified that much of the site was underlain by a former licensed and unlicensed landfill site.
The dynamic sampling/ windowless sample boreholes and trial pits, together with contamination laboratory testing, identified the site to be underlain by made ground/ fill, most of which comprised locally derived soil with no significantly elevated levels of contamination; however, localised areas of elevated levels of contamination were identified.
A detailed quantitative risk assessment (DQRA) was undertaken, which included bioaccessibility testing and modifying the exposure duration within the CLEA model, to demonstrate that whilst some of the recorded levels of contamination might exceed the generic assessment criteria (GAC) for a standard residential land use, the recorded levels of contamination were unlikely to be harmful to human health given the proposed end use.
Particularly high levels of ground gas (methane and ground gas) have been recorded. Long-term gas monitoring and a large dataset has been required to undertake a robust ground gas assessment, where peak and steady flow rates and maximum concentrations, together with groundwater level and atmospheric pressure fluctuations, have been studied in detail to ensure the correct site characterisation and gas protection measure proposals.
Continuous client and local authority engagement together with clear reporting have been crucial at this site to ensure that relatively complex issues were understood by all and the relevant planning conditions have been discharged.