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Morning All I meant to post the replies on this back in January. Better late than never!! I assume you mean clr 7 annex statistics tests not clr 9 I would consider the use of bre cover systems to be appropriate with the cieh statistics as the models haven't changed merely the guidance on their appropriate application has changed The next issue is will a bre cover system break all of the appropriate pollutant linkages as a maximum cover thickness of 600mm is usually adopted. This is acceptable for residential without plant uptake and commercial sites. However if plant uptake and soil attached to plants is a potential pathway a cover layer of less than 600mm is not appropriate because for 2 reasons 1 people growing their own vegetables often undertake an activity known as double digging where they dig down 2 spade depths (400-600mm depending on the size of the spade) this will bring contamination to the surface 2 the root zone of most plants is between 200 - 500 mm below the surface this means any cover system that does not include this entire zone is inappropriate for a residential with plant uptake or an allotment land use Hi Kay, as a former CLO, i would have thought BRE would work better with CIEH/CLAIRE as the latter should give you greater confidence in the stats then CLR7 best regards I don't think there is any great issue between using the new and old stats. I would be careful using the BRE cover calculator though. I have several issues with it and it doesn't take into account several things and should only be used for simple cover systems and low contamination. If this is to be used in a sensitive setting such as a garden, then human activities such as double digging etc the odd pond here and there etc need to be considered. For this reason I always insist on a minimum 600mm (can increase depending on what is present) with a physical break layer at the base (assuming no mobile or leachable contamination). I would say that's fine. Surely its all about deriving a representative concentration- for use in the model. Cheers Kay Wilcox| Contaminated Land Officer| Breckland Council Office: 01362 656870 DDI: 01362 656334| Fax: 01362 693733 [log in to unmask] <mailto:[log in to unmask]> | www.breckland.gov.uk <http://www.breckland.gov.uk/> ******************************************************************** Unless expressly stated otherwise, the contents of this e-mail are confidential, represent only the views of the sender expressed only to the intended recipient and are not intended to impose any legal obligation upon Breckland Council. If you are not the intended recipient, you are asked to notify the sender and delete the message as soon as possible. ********************************************************************