I think the question of how you would be required to demonstrate, with an acceptable level of uncertainty that 80% removal has been undertaken, particularly given the limited scope of some of the intrusive site investigations that cross some of our desks.
Kind regards
Ruth
Ruth Willcox
Environmental Protection Officer
Public Protection Services
Plymouth City Council
Civic Centre
Plymouth
PL1 2AA
T +441752304154
E [log in to unmask]
www.plymouth.gov.uk
-----Original Message-----
From: Contaminated Land Management Discussion List [mailto:[log in to unmask]] On Behalf Of Russell Corbyn
Sent: 18 August 2014 10:43
To: [log in to unmask]
Subject: Re: question about uk vs French methodology
Sorry for the late reply
I know what you are saying Mike and I hear you all loud and clear but...
It is taken that generally we know roughly where all the contamination is on a site (via Desk Study) and that hotspots are the main problem and we should be able to identify them etc.
However, I have rarely been on a brownfield/contaminated site where this ends up being the case due to the vast ranges of types of contamination: gas, pervasive PAH, pervasive metals, asbestos, and so on.
I just think we need to be careful of dumbing down. An 80/20 rule in my mind is just that. Rules of thumb can all too quickly be adopted as "Burger Van Rules" by non-specialists that may even be involved in signing off the site ("oh it's alright, we've probably got 80% out of the way now....").
As lovely and fluffy as things can be in this world [probably in some leafy suburb ;)] people will use things to their advantage when it suits them to apply pressure. Then comes the question of what other rules apply... 3 second rule? ;)
All the best
Russell
-----Original Message-----
From: Contaminated Land Management Discussion List [mailto:[log in to unmask]] On Behalf Of Michael Smith
Sent: 14 August 2014 08:49
To: [log in to unmask]
Subject: Re: question about uk vs French methodology
Russell,
There seems to be some misunderstanding here.
You "remove" 20% of the soil and consequently remove 80% of the "problem". The remaining 20% is not ignored - the risk assessment can then be revised and a decision made as to whether any further action is required. On a seriously polluted site, you could act quickly to deal with the major problem and then take more time to decide what to do in the longer term. Otherwise, you risk taking five-years to come up with the ideal solution whilst the site continues to impact various receptors.
You could view it is as a form of hot-spotting.
And to continue that line of thought, and referring to the need to follow BS10175, it might drive people to do better SIs. Too often, removing a few hot-spots is seen as solving the problem completely, when the SI is not capable of having found more than, for example, 50% or less of hot-spots (however, these are defined in a particular case).
We have guidance on how many samples to take to find hot-spots of a particular size - but I have yet to see any reference in an SI report to that guidance and the confidence that there can be that all hot-spots have been identified.
Regards,
Mike Smith
-----Original Message-----
From: Contaminated Land Management Discussion List [mailto:[log in to unmask]] On Behalf Of Russell Corbyn
Sent: 13 August 2014 15:18
To: [log in to unmask]
Subject: Re: question about uk vs French methodology
Come again?
Do we stop doing science now then and just remove 20% of the problem?
I'm sure there are cases where it will work and those where it won't. But because something isn't yellow doesn't mean it is green. Many things are interesting but that doesn't make them in anyway robust.
Where does this stop or be rationalised?
Has it actually resorted to this?
Russell
"There is a straw somewhere that will make a difference."
-----Original Message-----
From: Contaminated Land Management Discussion List [mailto:[log in to unmask]] On Behalf Of Chris Dainton
Sent: 12 August 2014 18:56
To: [log in to unmask]
Subject: Re: question about uk vs French methodology
The 80/20 rule does appear (quick Wiki search) to have been applied in occupational health and safety (not followed up references):
http://en.wikipedia.org/wiki/Pareto_principle
Interesting concept - not one that should be dismissed immediately.
This made me chuckle:
"Pareto developed the principle by observing that 20% of the pea pods in his garden contained 80% of the peas."
Chris Dainton
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