Here is something to get the grey matter working.
Has any one any oppinions on this.
A former gravel pit.
Used as a highways depot.
to be developed as residential use with mixed houses and flats.
Initial report indicated PAH's of ~1,000mg (1997)
later report indicated SEM(TEM) of ~2000mg and PAH's of ~300-400(2002)
Visual observations confirmed road scalpings
Gas survey and spike testing indicated no volatiles.
We agreed 1m of clean across the sites and gas membranes in premisses.
Residents were not happy about the development and mounted a campaign
regarding removal of carcinogenic waste (we had given a councilor a copy of
the 2nd report and explained to her the chemistry of PAH)
We commissioned second oppinion and then asked the developers consultant to
do Speciated TPH with Aliphatic aromatic splits. SVOC/VOC.
Results came back as C12-C35
C12-C16 ~10-20mg
C16-C21 ~50-80mg
C21-C35 ~500-900mg
Having put the data into the CLR7 stats tests
X mean C21-C35 = 574
US95 C21-C35 = 673
total numbers are less favourable as there is a significant aromatic load
but even so total TPH numbers are
X mean 1033mg
US95 1302mg
My oppinion is that given the other data and the uniformity of the fill the
site has been adequately characterised and I personally feel that
<100mg of C21-C35 @ 1.0m is still a conservative clean up standard, provided
we have a decent break layer in the gardens.
The problem is I dont see how you can model it when it supposedly is not
volatile.... and we have 1.0m of clean.!
Any thoughts.
________________________________________________________________________
This e-mail has been scanned for all viruses by Star Internet. 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
________________________________________________________________________
|