Thanks everone, all the messages have been very useful.
Essentially this is for ground water risk assessment (EA Remedial
Targets). In regards to Dan's comment below regarding porosity - I've
played with Level 3 with a range of porosity literature values for
Mudstone. The literature gave a total porosty range between 2 and 25%.
This resulted in a remedial target that varied from ~1ug/l to 240mg/l so
this would indicate that the RTM is fairly sensitive to porosity ????
Don't know if anyone has any comments on this...
Anyway, will see what the lab results flag up. Thanks again.
Chris
-----Original Message-----
From: Contaminated Land Management Discussion List
[mailto:[log in to unmask]] On Behalf Of
McMahon, Paul
Sent: 15 July 2008 13:50
To: [log in to unmask]
Subject: Re: Effective Porosity?
The link below might help too .....
Total Porosity (see Section 3) and Effective Porosity (see Section 4);
Meaurement procedure (see Section 4.2).
http://web.ead.anl.gov/resrad/datacoll/porosity.htm
Stepping back a little though, how accurately do you need to assess the
effective porosity, given the natural variability of soils and also by
reference to Dan's comments below about the assumed value for porosity
being relatively insensitive when using calculations to predict
contaminant migration.
Regards,
Paul
________________________________
From: Contaminated Land Management Discussion List on behalf of Dan
Riding
Sent: Tue 15/07/2008 12:49
To: [log in to unmask]
Subject: Re: Effective Porosity?
Chris,
Please be aware that these laboratory tests will only provide you with
total porosity (total voids). Effective porosity is dependent on
whether the voids in the soil/rock are interconnected and therefore can
only accurately be determined through large scale field tests and
calibration of models.
However as the calculation for contaminant migration are not very
sensitive to porosity, published values for typical soils and rock are
usually adequate.
Dan Riding
-----Original Message-----
From: Contaminated Land Management Discussion List
[mailto:[log in to unmask]] On Behalf Of
McMahon, Paul
Sent: 15 July 2008 10:37
To: [log in to unmask]
Subject: Re: Effective Porosity?
Hi Chris,
Any reputable geotechnical laboratory could make this determination for
you.
They will need to determine bulk density, moisture content and specific
gravity for the various soil fractions present in your soil to determine
the void ratio and hence porosity. You are also likely to require a
particle size analysis and/or sedimentation test to assess the overall
variability of the soil, since it may not have a unique porosity, but
moreover it will vary.
Unfortunately I do not have current laboratory testing rates but these
are NOT expensive tests. It would be inappropriate of me to recommend a
specific laboratory for you to approach, but there are many.
Good Luck.
Regards,
Paul
Dr. Paul H. McMahon
Senior Geotechnical Lecturer
Built Environment & Civil Engineering
University of Bolton
Deane Road
Bolton
BL3 5AB
Direct Line: 01204 903849
http://www.bolton.ac.uk/staff/phm2
<https://webmail.bolton.ac.uk/exchweb/bin/redir.asp?URL=http://www.bolto
n.ac.uk/staff/phm2>
________________________________
From: Contaminated Land Management Discussion List on behalf of Chris
People
Sent: Tue 15/07/2008 10:06
To: [log in to unmask]
Subject: Effective Porosity?
Morning Everyone.
Does anyone have any experience of assessing Effective Porosity? I
presume you may need a U100 to be tested - but cant find any further
information on it.
Is there a standard lab test that can provide this? If so do you have
any
idea of a approximate cost?
Thanks!
Chris
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