Afternoon all,
A local consultant has made me aware that the NHBC have just published revised guidance on validating cover systems / topsoil in issue 8 of Technical Extras:
http://www.nhbc.co.uk/Builders/ProductsandServices/TechnicalExtra/
I had a brief discussion with the consultant about the guidance and we shared the same concerns. Consequently I wondered whether list members were aware of the guidance and whether others had similar concerns. My concerns include:
1. I can't agree that soils raised from agricultural land would not need testing (pesticides, herbicides, fungicides, fertilisers, PAHs (stubble burning) etc etc);
2. I would also need convincing that any topsoil manufactured from a waste stream, green or not, would not require any testing at all (although in reality I guess it would probably be subjected to a certain degree of testing as part of manufacturer QA/QC?); and
3. I cannot agree that imported topsoil which is, "...not being used as a cover system as part of a contamination remediation strategy..." will not require testing. There is no logic to that statement at all. If you place contaminated top soil over clean or contaminated subsoil the result is the same: a viable pollutant linkage. In my opinion a developer must be able to PROVE that ANY topsoil / subsoil imported onto site is suitable for the intended end use. If that use is residential then the chemical composition must be judged against current SGVs / GACs etc etc.
Maybe I’m being overly conservative so I would be very interested in other opinions. I’m not convinced that this document is very helpful and I expect that it will be cited in many validation reports to justify no / low level testing. I am curious as to how the HNBC formulate such guidance and whether any regulators etc are consulted during the process so if any NHBC list members could comment I would be very grateful.
Thanks,
Mark.
Mark Seaman
Waveney District Council
Environment Protection Officer
01502 523153
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