NYC-WTC_000189687

NYC 9/11 Public Portal Document

Mr. Bernard P Orlan January 10, 2002 Air Sampling for Metals & Mercury Page 2 HS for Leadership & Pub Service ('894M') ATC Protect No. 15-19125-0290

AIR SAMPLE RESULTS - METALS

The metals that were found above the limits of detection were chromium, copper, iron and zinc The other seven metals were not detected. Table 1 lists the metals that were detected and their respective concentration ranges. TABLE 1 DETECTED METAL CONCENTRATIONS (mg/m’ *) . .... ........I! Chromium 0 000281 -0.000425 **BDL-0.000244

Copper BDL-0 00109 BDL-0.000214

Iron BDL-0.00776 BDL-0.0183

Zinc BDL-0.000424 BDL

milligrams per cubic meter of air **BDL = Below Detection Limit

Chromium was detected in six of the seven indoor samples and in the outdoor sample from the roof Copper was also in six of seven indoor samples Copper and iron were m the outdoor sample from the mam entrance but neither were of these metals were in the roof sample. Iron was in three indoor samples. Zinc was detected m only one sample, indoors in the Library, it was not detected outdoors.

The Environmental Protection Agency (EPA) has set a screening level for hexavalent chromium m air of 0.6 ug/m\ this assumes a continuous exposure for one year. The samples here were analyzed for total chromium (tnvalent and hexavalent). The concentrations are below the EPA level. The EPA has no published screening level or guideline for copper, iron or zinc.

MERCURY SAMPLE RESULTS

Air samples for mercury vapor were collected at the same locations as those for metals No sample contained mercury at a concentration greater than that detected in the blank

ATC appreciates the opportunity to provide this indoor air quality service to the BOE. Please call me at (212) 353-8280 extension 212 if you have any questions.

Sincerely, ATC Associates, Im

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

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NYC-WTC_000189688