NYC-WTC_000219113

NYC 9/11 Public Portal Document

Mr. Bernard P. Orlan March 20, 2002 Wipe Samples for Dioxins Page 2 P. S. 89 ('Manhattan) ATC Project No. 15-19125-0297

ATC submitted three (3) wipe samples for PCDDs/PCDFs (plus one blank) to Pace for analysis. Copies of the draft laboratory analysis results are provided in Attachment 1. Samples were taken from areas specified by the parents association consultant. The sample area was one square meter (m^).

Each sample was analyzed for sixteen (16) PCDD/PCDF isomers. The results for each isomer were then converted to 2, 3, 7, 8 -tetrachloro-dibenzo-p-dioxin (2, 3, 7, 8-TCDD) equivalents by multiplying by an established equivalency factor. This provides a single value (in nanograms) for the analytical results for each sample. The sample locations and the results are shown in the table:

DIOXIN WIPE SAMPLE RESULTS (2, 3, 7, 8 TCDD EQUIVALENTS) February 14,2002

(Illi/in-, 1st Floor Hallway-north/DXl 0066070 1 st Floor Hallway-south/DX2 Oo” 2^“^ Floor Hallway-south/DX3 0.000050 Field Blank/DX4 0.0025

The concentrations on indoor surfaces ranged from 0.000050 to 0.000070 nanograms per square meter (ng/m^). The dioxin concentrations in these sample are below the NYSDOH guideline.

It is not possible to determine when the 2, 3, 7, 8 - TCDD equivalents detected in these samples were deposited. Dioxin samples were not collected from these locations prior to December 20, 2001.

It is our pleasure to provide these indoor environmental services to the NYC Board of Education. If you have any questions about this report, please call (212) 353-8280, extension 212.

Sincerely, A TC ASSOCIA TE^C.

James R. Cohn, CIH, CSP Regional Manager Industrial Hygiene Division

Attachment

CITY_21MC100_002879291

NYC-WTC_000219114