St Leonard’s Court, Sandridge: groundwater pollution remediation

St Leonard’s Court, Sandridge, is a small residential development built in 1986-7. The land was previously used as a chemicals factory, manufacturing brominated compounds between approximately 1955 and 1980.

Historic contamination of this land has caused a plume of bromate and bromide in groundwater, stretching approximately 20 kilometres from the source, impacting public and private water supply abstractions, and discharging via natural springs into the River Lee.

The pollution is currently managed by ‘scavenge pumping’, a process whereby the contaminated groundwater is pumped from a closed public water supply well, treated and discharged to foul sewer. Groundwater from the other public water supply abstractions is blended to ensure it meets drinking water standards. The affected private water supply abstractions are restricted in their use.

Under the Environmental Protection Act 1990, Part IIA (Part IIA) and associated contaminated land regulations, St Leonard’s Court was determined as a contaminated land site by St Albans District Council on 20 June 2002. On 8 August 2002 it was designated a special site, thereby transferring responsibility for enforcement from the Council to the Environment Agency.

We identified the parties responsible for the pollution, called the Appropriate Persons under Part IIA, as two companies: Crest Nicholson Residential PLC (Crest) and Redland Minerals Limited (Redland). In 2005, we served a remediation notice on them. Both companies appealed against the notice. The appeal was heard at a public inquiry in 2007. The Secretary of State for the Environment issued a decision on 22 July 2009. This upheld the actions of the notice that the Environment Agency recommended to the Inspector at the appeal hearing, but slightly varied the division of responsibility between Crest and Redland (the First Notice). The First Notice is appended to the Consultation Document.

Crest and Redland have so far completed 11 of the 12 actions in the First Notice. The remaining action is the ongoing procurement of the interim scavenge pumping from the well that was closed for public water supply. This action will expire on 21 July 2019. We are working to ensure the interim scavenge pumping does not cease on this date, because it is essential in managing bromate and bromide concentrations at downstream public water supply wells.

The Appropriate Persons and the owners of any land to which the notice relates (the statutory consultees) have received hard copies of the consultation document. This represented the start of a statutory consultation period on the next phase of remedial actions, as required by Section 78H(1)(b) of the Environmental Protection Act 1990.

This online consultation is to allow participation from others, including local interest groups, industry and academia.

The key documents can be found in the Consultation Hub. Some documents are hard copy only and must be viewed in person at the Environment Agency’s Hertfordshire and North London Area office at: Environment Agency, Customers and Engagement, Alchemy, Bessemer Road, Welwyn Garden City AL7 1HE