The HELGA model was developed by Atkins and many features were incorporated into CLEA. I have it as a spreadsheet somewhere and can send to anyone that is interested. It is however >6yrs old and I have not used it for a long time.
Adam
________________________________
From: Contaminated Land Management Discussion List on behalf of Willcox, Ruth (DEVELOPMENT)
Sent: Wed 04/08/2010 10:49
To: [log in to unmask]
Subject: Re: Contamination Depth and Vegetable Uptake
Hi Steve
Are you aware of any modelling guidance, tools or methodology for my
reference. I am aware of dispersion modelling techniques, CIRIA C665
and gas/vapour risk assessment principles.
If anyone is aware of anything pertinent please feel free to enlighten
me!
Regards
Ruth
Ruth Willcox
Environmental Protection Officer (Land Quality)
Plymouth City Council
Public Protection - Floor 6
Civic Centre
City Centre
PLYMOUTH
Devon
PL1 2AA
Tel: 01752 304154
Fax: 01752 226314
Email: [log in to unmask]
-----Original Message-----
From: Contaminated Land Management Discussion List
[mailto:[log in to unmask]] On Behalf Of Steve
Wilson
Sent: Wednesday, August 04, 2010 10:11 AM
To: [log in to unmask]
Subject: Re: Contamination Depth and Vegetable Uptake
Themis
A hydrocarbon resistant membrane may not be sufficient on its own to
deal with vapour pathway. They are not totally impermeable to vapours
and when considering the very low allowable concentrations internally
may not remove the pathway.
You should model the effect of the membrane in your risk assessment to
make sure it reduces migration sufficiently.
Steve Wilson
Sent using BlackBerry(r) from Orange
-----Original Message-----
From: Themida Kantara <[log in to unmask]>
Sender: Contaminated Land Management Discussion List
<[log in to unmask]>
Date: Wed, 4 Aug 2010 09:33:51
To: <[log in to unmask]>
Reply-To: Themida Kantara <[log in to unmask]>
Subject: Contamination Depth and Vegetable Uptake
Dear All,
many thanks to all those who replied. The general concensus is that just
600mm of topsoil cover might not be adequate but it also depends on the
amount and type of contamination. Some with arboricultural experience
also commented that for medium sized trees a good 2m of good quality
soil is required. Of course everyone commented that the vapour pathway
could be the predominant exposure route. I should have mentioned on my
original memo that the TPH levels are up to 30000mg/kg (and at depth up
to 2.5mbgl). They will put a HC/vapour resistant membrane for the
buildings.
I think that a lot more information will be required on this subject
before I accept the magic number (which the report states that is the
standard BRE guidance).
Once again thank to everyone for their help (Albert thank you for the
attached docs I am sure they will make an interesting reading).
Regards
Themis
********************************************************************************************************************************************
IMPORTANT: This e-mail (including any attachments to it) is strictly confidential and intended solely for the person or organisation to whom it is addressed. It may contain privileged, confidential or sensitive information. If you are not the intended recipient, you must not copy or distribute it to any other person or take any action in reliance. If you have received it in error, please notify your system manager and the sender as soon as possible and then delete it from your system.
|