NYC-WTC_000202178

NYC 9/11 Public Portal Document

(Smtc A S S 0 C I A T E S I N C . 104 East 25th St., 10th Fl New York, New York 10010 wv\'w. ate-e n vi ro. co rn 212.353,8280 ■ Fax 212.353.8306

October 3, 2002

Mr. Bernard P. Orlan Director, Environmental Health & Safety New' York City Department of Education 28-11 Queens Plaza North Long Island City, NY 11101-4008

Re: Wipe Samples for Dioxins F.S.89M ATC Project No. 15-19125-0297

Dear Mr. Orlan:

ATC Associates Inc.- (ATC) is pleased to provide this report of the results of the wipe samples for polychlorinated dibenzo-p-dioxins (PCDDs)and dibenzofurans (PCDFs) collected on August 20, 2002 at the referenced location. The New York City Board of Education (BOE) requested these samples to evaluate possible contamination in the school building. ,

SCOPE OF WORK

The samples were collected using gauze pads and hexane as a solvent. The pads and solvent were provided and samples were analyzed by Pace Analytical Services, Inc. (Pace) of Minneapolis, MN, a laboratory experienced in dioxin analysis. The analysis was performed by modified EPA Method 8290 using combined capillary column gas chromatography/high resolution mass spectrometry. .

Tenzin Namgyal, Industrial Hygienist of ATC’s New York City office, collected the samples consistent with generally accepted industrial hygiene practices. There were inherent limitations created by constraints of time, operational and work practice variability, variations in contaminant concentrations, and sampling and analytical accuracy. The results of the sampling represent conditions found on the date the samples were collected.

WIFE SAMPLING RESULTS

ATC submitted three (3) wipe samples for PCDDs/PCDFs to Pace for analysis. A copy of the laboratory analysis report is provided in the Attachment. The area of each sample one (1) square meter (Im^).

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.

CITY_21MC100_003270394

NYC-WTC_000202178