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Why do modern gps and gis systems negate the need to increase your chances of detecting elongated hotspots? Gareth Rees Contaminated Land Officer, Harborough District Council, Tel: 01858 821174 ________________________________ From: Contaminated Land Management Discussion List [mailto:[log in to unmask]] On Behalf Of Ivens, Rob Sent: 11 September 2007 10:32 To: [log in to unmask] Subject: Re: CLR7 Test At risk of carrying on the pain.. you don't need to use a herringbone... we never have not with modern GPS and gis systems. I wouls allow an elavetd value in a garden... it is simply a representation of the real world.... The clever bit is giving it the context to make a decision. BUT if you can show that (internally homogenous) ZONES, that may comprise several averaging areas, of the site are suitable for specific land uses then fine. I would sugest that this is the key- why assess every garden if the area is similar an estimate of the population can be obtained from sufficient sampling across the area... Attached is a jpg of a boundary area of a site we investigated- 25 houses on the edge of a clay pit assumed clean and how we divided up the work. Ps I would not rely on the outlier test to pick up hot spots Cheers. Rob Ivens Scientific Officer 01306 879232 ________________________________ From: Contaminated Land Management Discussion List [mailto:[log in to unmask]] On Behalf Of Adam Czarnecki Sent: 10 September 2007 10:16 To: [log in to unmask] Subject: Re: CLR7 Test I thought so every answer received so far different.... which just highlights the problems we are experiencing. The point was entirely academic and it could have been any potential contaminant. The outliers were not identified using the Max Value Test..Mean + 2StandardDev should tell you that. I can understand the reluctance to allow an isolated elevated concentration in a garden, however does this mean you need to treat each garden as an averaging area? If the site was a commercial end use, would anyone be worried about the outliers? -- Adam Czarnecki Head of GeoEnvironmental Division Clancy Consulting Ltd. Dunham Court 2, Dunham Road Altrincham Cheshire WA14 4NX Tel: 0161 613 6000 Fax: 0161 613 6099 Clancy Consulting Ltd. Registered Office: 2 Dunham Road, Altrincham, Cheshire, WA14 4NX Registered in England No: 3693529 We cannot accept any liability for any loss or damage sustained as a result of software viruses. It is your responsibility to carry out such virus checking as is necessary before opening any attachment. The information contained in this message is private and confidential. It is intended only for the use of the named E-Mail addressee. If you are not the named E-Mail addressee please E-Mail or telephone us immediately with your confirmation that you have destroyed it. In no event should you disclose the contents of this E-Mail to any other person nor copy, use, print, distribute or disseminate it or any information contained in it. Thank you for your co-operation. Please visit our website at www.clancy.co.uk ________________________________ From: Contaminated Land Management Discussion List [mailto:[log in to unmask]] On Behalf Of Steve Buss Sent: 07 September 2007 13:31 To: [log in to unmask] Subject: Re: CLR7 Test Sarah, I only know that ESI sent our part of this to Defra in March and we understand it's now out to a select group of consultees. We weren't working for the EA - perhaps there's another project? Cheers Steve Buss Principal Hydrogeologist, ESI ________________________________ From: Contaminated Land Management Discussion List [mailto:[log in to unmask]] On Behalf Of Sarah Dack Sent: 07 September 2007 13:20 To: [log in to unmask] Subject: Re: CLR7 Test Does anyone know when guidance is due to come out on sampling and stats? I understood that ESI, Atkins & RSK were working on guidance for stats on an EA R&D project, but thought it was due out earlier this year. Still nothing can beat a bit of common sense and a good site understanding! Sarah Dack Principal Risk Assessor DD - 0151 348 8106 ________________________________ From: Contaminated Land Management Discussion List [mailto:[log in to unmask]] On Behalf Of Paul Nathanail Sent: 06 September 2007 18:15 To: [log in to unmask] Subject: Re: CLR7 Test Adam, If you have 5 outliers then they are drawn from a different population than your other 45 samples and must be considered separately. Statistically the us95 including proven outliers is meaningless. There are lots of caveats to the above - how do you know they are outliers, how far above a GAC are they, what soils were sampled etc etc - but the above gives a straight answer to your straight question. BTW I am surprised at such a low remedial target for arsenic! why do you have a remedial target (and presumably therefore a source management form of remediation) while you are still thinking about the risk assessment? Best regards, Paul Nathanail Paul Nathanail SiLC Professor of Engineering Geology & Head of Land Quality Management School of Geography, University of Nottingham, Nottingham NG7 2RD, UK ----- Original Message ----- From: Contaminated Land Management Discussion List <[log in to unmask]> To: [log in to unmask] <[log in to unmask]> Sent: Thu Sep 06 16:47:16 2007 Subject: CLR7 Test A simple one for you... If you perform a CLR7 test and determine that for example the upper 95%ile estimate of the population mean for arsenic is below the site specific remedial rarget of 20mg/kg (residential end use) what would you report if five(out of a dataset of 50) of the sampled concentrations are outliers? Assume that the development is part of a planning application, not a Part IIa determination and that all samples are from a topsoil material at 0.5m depth. Would you: a) Determine that there is a need to investigate the outliers as they represent contamination hot-spots; or b) Determine that there is no need for any further assessment. We (as consultants) are facing different interpretations of the CLR7 test from local authorities and have also peer reviewed a fair number of other consultants reports which also have varying opinions. Adam The information in this e-mail is confidential and may be legally privileged. It is intended solely for the addressee. Access to this email by anyone else is unauthorised. Any views or opinions expressed in this e-mail may be solely those of the author and are not necessarily those of Mouchel Parkman Mouchel Parkman Services Ltd, Registered in England at West Hall, Parvis Road, West Byfleet, Surrey UK KT14 6EZ Registered No : 1686040 ________________________________________________________________________ This e-mail has been scanned for all viruses by Star. The service is powered by MessageLabs. For more information on a proactive anti-virus service working around the clock, around the globe, visit: http://www.star.net.uk ________________________________________________________________________ ________________________________________________________________________ This e-mail has been scanned for all viruses by Star. The service is powered by MessageLabs. 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