Spelthorne Borough Council

Providing Quality Services to the People of
Ashford, Laleham, Shepperton, Staines, Stanwell & Sunbury

Latest contaminated land information

This page includes further information about the investigation and clean up of land determined as Contaminated Land under Part IIA of the Environmental Protection Act 1990, including copies of Determination Notices and Remediation Statements from the Part IIA Remediation Public Register.

The Council is not currently involved in any intrusive investigations of potentially contaminated land in accordance with its duties under Part IIA. As and when this occurs, information will be provided on this page to keep local residents up to date on such investigations.

Public Open Space, Denman Drive, Ashford

Introduction
An area of public open space at Denman Drive, Ashford was determined as Contaminated Land in May 2011 following detailed inspection of a former landfill at Denman Drive, Mayfield Close, and Caroline Court. No properties at the estate were found to be on contaminated land, as defined by Part IIA of the Environmental Protection Act 1990.

Summary of the investigation and clean-up

During Phases 2 and 3 of the investigation, the Council determined that land at Denman Drive, Mayfield Close and Caroline Court is not contaminated land due to ground gases, groundwater pollution or sulphate attack on foundations.

This completed the investigation, by September 2009, for all but a handful of properties at the estate.

During the Phase 4 investigation, additional soil sampling was done at a small number of properties and two areas of open space. The conclusion of Phase 4 was that the land at these properties is not contaminated land, as defined by Part IIA of the Environmental Protection Act 1990.

Land at one area of public open space at the green in the centre of Denman Drive has been determined by the Council, on the basis of the work by our consultants, to be Contaminated Land in accordance with Part IIA of the Environmental Protection Act 1990. The land was contaminated by virtue of elevated levels of cyanide in shallow soils. These soils could have caused serious harm to young children if accidentally ingested. The contamination is from black ashy sand material deposited before the housing was built and the land was part of a landfill tip. The contaminated material is likely to have been waste from the manufacture of town gas at a gas works site.

The contaminated land was subject to clean-up in August 2011. Shallow soils were dug out and new clean soils placed over a special plastic layer. Unfortunately two trees had to be removed during the work, but these were replaced with young saplings. Turf has been laid and the site re-opened in early September 2011 once the turf had become established.

Further information
Part IIA Remediation Register Entry
Record of Determinaton
Remediation Statement

56 Station Crescent, Ashford

Introduction
The land determined relates to part of the former plot of 56 Station Crescent. The land was being redeveloped under the planning regime. However the original developer pulled out when their site investigation revealed a former Victorian borrow pit on the rear of the site, where the ashy fill materials contained elevated levels of polycyclic aromatic hydrocarbons (PAHs).

The land was subsequently determined as Contaminated Land in October 2000 due to a significant possibility of significant harm from elevated PAHs in shallow soils. The site was ultimately clean up by another developer during construction of 7 new residential dwellings on the site between October 2001 and March 2002. The land is now occupied by no.s 1 to 5 Lancaster Close, Ashford.

Summary of investigation and clean-up

WSP Environmental (WSPE) were initially commissioned to undertake a site investigation on the site in 1999. The result of the investigation highlighted the presence of an historic landfill to the rear of the site.

WSPE were subsequently commissioned by Landsdean Ltd to continue as environmental consultants throughout the investigation and clean-up. WSPE undertook a Quantitative Risk Assessment to assess the risks associated with the landfill to the existing residential property and proposed residential development. A Remediation Method Statement was produced for the site specifying the necessary remedial works, namely the import of clean inert materials to form a clean and distinct barrier between the contamination and the future residents. The degree of works required varied according to the end use of each section of site.

In summary, the remedial works comprised:

i)	Removal of contaminated soil from the rear gardens of the houses at the back of the plot and to the west of the central block of houses to be disposed of off-site;
ii)	Removal of contaminated soils from along the lines of any services and the culvert installed within the rear of the site;
iii)	Placement of geotextile barrier membranes as identification layers above the contaminated materials with a 250mm layer of crushed hardcore in between in rear garden areas;
iv)	Import of clean inert subsoil and clean inert topsoil to the depths of at least 750mm in the rear gardens and 600mm in front gardens and landscaped areas; and
v)	Collection of groundwater samples, before, during and after completion of the site works to ensure no derogation of the groundwater.

Further information
Part IIA Remediation Register Entry
Record of Determinaton
Remediation Statement

Contact us

The Pollution Control team will endeavour to keep residents as up to date as possible. In the meantime, should you have any queries, please don't hesitate to contact us

01784 446 251

pollution.control@spelthorne.gov.uk

Environmental Health, Council Offices, Knowle Green, Staines, TW18 1XB.

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