Ealing Council has also commissioned independent soil monitoring on the site. The first results are now available.
Hydrocarbons (including benzene, naphthalene and 4-isopropyltoluene), poly-aromatic hydrocarbons, metals and cyanide were identified as being present in the soil before development started. These chemicals are commonly found on sites previously used as gasworks; the remediation work is designed to treat the soil to deal with these contaminants. Very little asbestos was found and what was detected was in cement form. This was collected by hand, double-bag, labelled and safely removed from the site by qualified persons.
The contaminated soil has been treated using a process known as stabilisation/solidification. This involved treating the soil with lime, which immobilises the contaminants within a concrete-type material.
Treating contaminated land is a highly regulated activity. Ealing Council has received ongoing assurances from the Environment Agency, which is responsible for regulating the soil treatment, that it is satisfied that the proper mitigations are in place at the site. This includes a legal requirement for the developer to put in place air quality monitoring to ensure it is within the terms of the permit set by the regulator.
Officers from Ealing Council and the Environment Agency visit the site every month to ensure works are being carried out correctly. The officers liaise with representatives of the remediation contractor Blackwell, the supervising environmental consultant Atkins and developer Berkeley West Thames.