E-mails 2003 M. Gilsenan

NYC 9/11 Public Portal Document

Gtlsenan, Michael From: Theodorellys, Penny Sent: Wednesday, March 19. 2003 9:03 AM To: agasparro@jlcenvironmental .com Co: Radhakrishnan, Krish; Gilsenan, Michael; [email protected] Subject: 114 Liberty Sampling

The following are comments received from the USEPA for the analytical data received to date. The analytical sensitivity was an issue I had addressed with you as well. We discussed the matter and you had gotten clarification from the lab. Please contact Mr. Chuck Nace of the USEPA directly and address the comments below. (Chuck Nace, Environmental Toxicologist, USEPA - Region 2 212.637.3459/212.637.4164

Excerpts of the e-mail I received...

..... 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 OjS5M 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 O.i 9), 1 above health-based benchmark @ 0.0018 s/cc Asbestos/Fibrous Glass - PCM 3 samples were_^low the health-based benchmark of 0.01 f/cc and 2 samples were overloaded and could not be analyzed. Lead 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)......

1

NYC-WTC_000163074