Beethoven Street, Queens Park, London

Additional Contamination Investigation Report to define the condition of materials in select areas across the site which is being redeveloped as a new school

Project Overview:

The project was undertaken as an Additional Contamination Investigation Report to define the condition of materials in select areas across the site which is being redeveloped as a new school with an associated playground and playing fields previously on the site. This meant that a number of the old school buildings were in the process of being demolished at the time of the investigation. Access was further restrained by the presence of Knotweed and a Sub-Station with associated services. As part of the works, a complete service survey was also undertaken and helped advise on safe investigation locations. At all times social distancing was maintained at the site in compliance with current guidance and in consultation with the site.

What Soils Limited Brought To The Table

The Geology of the site comprised a variable Made Ground overlying London Clay at depth with no noted superficial deposits. Previous investigation by others had identified potentially elevated levels of contaminants typical of redeveloped areas found in London, mainly in the form of metals and PAH’s. These findings could present a risk to vulnerable receptors.

Works comprised 15no. 1m windowless sampler boreholes with 5no. locations in each of 3no. highlighted areas across the site where it was identified that potential risk may be present to vulnerable future receptors as identified in the initial Conceptual Site Model (CSM), i.e. areas of open space accessible to minors through the inhalation and exposure pathways. In addition, the investigation was also structured to provide information in relation to current waste and materials management guidance.

Samples were analysed from the whole range of the depth investigated, which was Made Ground to 1.00m below current ground levels at all points. Materials encountered were described to current UK/ISO standards for both soils and wastes and in line with the AGS guidance on Made Ground description. Samples were analysed at a Certified UKAS accredited laboratory following logging and scheduled for a generic suite based on the findings of the previous investigations and the identified potential risks noted in the initial CSM as required by current guidance.

A Tier 1 assessment of the results against generic guidance criteria was used assuming an Open Space Land use scenario and model. PAH ratio analysis identified 1no. outlier due to the presence of historic coal-based tarmacadam and determined the material as being most likely defined as non-hazardous in a waste context. The Local Planning Authority has been appraised of these findings and we await their response as to if a remediation strategy will be required under planning.

By undertaking this additional work, the Client is now in a much better position to comply with their planning obligations. It can now be seen to have followed the appropriate CDM and planning guidance in determining and assessing the key risk factors in the context of the proposed site development and gathering the evidence required to make justified and rational cost-benefit decisions in relation to the works that may be required.  Additionally, they are now able to determine their potential costs, works implications and duty of care obligations including Health and Safety.