NYC 9/11 Public Portal Document
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Gilsenan, Michael
From: [email protected]
Sent: Tuesday, March 18, 2003 11:59 AM
To: Theodorellys, Penny
Cc: Radhakrishnan, Krish; Gilsenan, Michael; [email protected];
[email protected]; [email protected]
Subject: Re: FW: PAH results US DEP - WTC
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Letter.pdf Report, pdf Letter.pdf Report, pdf
Penny,
I am back from vacation and had a chance to take a look at the data
(i.e., asbestos, lead and PAH) from 114 Liberty that you sent over last
week. Overall the data that you sent looks good but there are several
problems with the reporting limits (i.e., analytical sensitivity).
1) The PAH data indicates that the reporting limit used is 5 ug. This
does not allow us to compare the results to the health-based benchmark
because the reporting limit is higher than the benchmark. The reporting
limit that was supposed to be used was 1 ug (as stated on page 3, item
#5 in the scope of work). I hope future PAH analyses can use the
appropriate reporting limit as it will result in data that can be
compared to the health-based benchmark.
2) The asbestos data indicates that the reporting limit used is 0.0009
s/cc. This is acceptable for comparing to the health-based benchmark
but the reporting limit that was supposed to be used was 0.0004 s/cc (as
stated on page 4, Asbestos Collection and Analysis, item #2). Using the
lower reporting limit will add confidence that the concentrations are
below the health-based benchmark rather than being "at" the health-based
benchmark and it is also what is being used in our residential cleaning
project and it is what was used for 125 Cedar Street.
3) The lead data indicates that the reporting limit used is 20 ug/ft2.
Again, this is acceptable for comparing to the health-based benchmark of
25 ug/ft2, but for our projects we used a reporting limit of 2.32 ug/ft2
and a reporting limit of 9 ug/ft2 was used-for 125 Cedar Street.
A summary of the data I have received to data is presented below:
Asbestos - TEM
40 samples at or below the health-based benchmark of 0.0009 (28 were
below the reporting limit of 0.0009), 1 above health-based benchmark @
0.0018 s/cc
Asbestos/Fibrous Glass - PCM
3 samples were below the health-based benchmark of 0.01 f/cc and 2
samples were overloaded and could not be analyzed.
Lead I
13 samples were above the health-based benchmark of 25 ug/ft2 and 17
samples were below the analytical sensitivity of 20 ug/ft2.
PAH
30 samples were below the reporting limit of 5ug. The resulting TEF for
each sample would be 580 ug/m2 which is above the current health-based
benchmark of 300 ug/m2. This is why a reporting limit of 1 ug should be
used (i.e., item #1 above).
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