Agenda item

In their Remediation Method Statement discussing “Contaminants of concern” Vertase noted:

(A) The recommended targets produced by Atkins are certainly protective of all identified receptors …. However, for the avoidance of doubt we do not believe these targets are achievable through the use of readily available and commercially viable remediation technologies or without significant export of contaminated materials off site. (Page 60, Section 18.1)

(B) It does mean that some material will be replaced at the site that does not meet the present generic criteria  (Page 14, Section 6.4).

Which are, and what is the nature of the chemicals that cannot be remediated -  or not to the target levels - and so will be replaced and, more importantly, what measures  will be taken to isolate them to ensure the safety of humans and groundwater?

From Dr Charles Turner on behalf of the Cam Valley Forum to the Environmental Services Portfolio Holder:

“In their Remediation Method Statement discussing “Contaminants of concern” Vertase noted:

“(A) The recommended targets produced by Atkins are certainly protective of all identified receptors …. However, for the avoidance of doubt we do not believe these targets are achievable through the use of readily available and commercially viable remediation technologies or without significant export of contaminated materials off site. (Page 60, Section 18.1)

“(B) It does mean that some material will be replaced at the site that does not meet the present generic criteria  (Page 14, Section 6.4).

“Which are, and what is the nature of the chemicals that cannot be remediated -  or not to the target levels - and so will be replaced and, more importantly, what measures  will be taken to isolate them to ensure the safety of humans and groundwater?”

The Environmental Services Portfolio Holder replied, “The statements quoted from the Remediation Method Statement need to be read in the context of the sections from which they have been taken.  These sections set out the possibility of reviewing the numbers that were used for the computer model to calculate the target levels for remediation. The numbers currently used are very conservative estimates, however, through the excavation and remediation process more accurate numbers will be measured on site and these can be used in the models to produce new targets.

“Any proposed changes to the remediation targets following such a review of the computer model would have to be submitted and agreed as set out in condition 2 of the planning consent.

“The Remediation Method Statement correctly identifies that some contaminants are more treatable than others.  South Cambridgeshire District Council and the Environment Agency will not accept the replacement of any soil that does not comply with agreed remedial targets.  Any soils that, after extensive treatment, still have contaminant concentrations exceeding the agreed targets will need to be exported off site to a suitable licensed landfill.  This is covered in the Remediation Method Statement to ensure that the treatment of excavated soil is comprehensive and that there is an appropriate option for all material that may be found on site.”

Dr Turner asked, as a supplementary question, "So you don't know whether there is a material that cannot be remediated?", to which the Environmental Services Portfolio Holder replied that the Council did not.

Dr Turner further asked, "In a letter to the Council from GTA Grimley in a report to Natural England, the cover system was designed to be protective to human health and must not be breached.  In a response from Claire Sproats, the human health targets are limited to the top 1 metre.  There must be some materials affecting human health and getting into the drainage system - do you regard as satisfactory the solution / remediation strategy which accepts that there are contaminants underneath and a cover on top?"  The Environmental Services Portfolio Holder promised Dr Turner a written response.