Memo re: environmental monitoring, 1 North End Ave, Nov 2001

NYC 9/11 Public Portal Document

ambient group inc. NATIONAL HEADQUARTERS

Indoor environmental quality surveys 55 WEST 39T STREET I2n FLOOR Water treatment consulting

O ® Asbestos & lead field services Regulatory compliance programs NEW YORK, NEW YORK IOO18 TEL: (2Iz) 463-7812 FAX: (212) 463-9397 Air, water & soil analytical laboratories WEB: WWW.AMBIENTGROUP.COM

November 1, 2001

Mr. Elliott Zuckerman Director of Pldperty Management New York Mercantile Exchange 1 North End Avenue New York, New York 10282

Re: Environmental Monitoring for Combustion Byproducts

Dear Mr. Zuckerman:

In order to address additional environmental concerns raised by the prolonged combustion processes that continues at the World Trade Center site, in early October your firm directed Ambient Group, Inc. to acquire specific sampling equipment and perform additional analysis of environmental compounds that might be generated by the combustion process. The equipment used and the analysis performed were chosen in accordance with EPA Compendium of methods for the Determination of Toxic Organic Compounds in Ambient Air. Samples were analyzed for chlorinated dioxins, PCBs, brominated dioxins and polycyclic hydrocarbons (PAHs). The four groups represent over 300 types and/or isomers of chemicals that are known to be hazardous substances associated with combustion.

Ambient air analysis, as opposed to occupational analysis, has many unique differences that make sampling, analysis and interpretation difficult. For instance, ambient sampling requires a very large sample volume for analysis, which in turn requires specialized equipment and a lengthy sampling period. In addition, each group of diverse compounds must be prepared separately and analyzed by distinct procedures. Finally, there are no reference standards with which to compare the results of airborne concentrations in order to determine the health risk to office workers.

One approach which is often used is to transform the air concentrations of all the different specific congeners of PCBs, dioxins and furans into Toxicity Equivalents (TEQs) of 2,3,7,8 (2,3,7,8 TCDD). 2,3,7,8 TCDD is thought to be the most hazardous of this group tetrachloro-p-dioxins of compounds and is given a weighting of 1, while other less toxic compounds are given a weighting of less than I relative to 2,3,7,8 TCDD.

With that said, our preliminary findings indicate that the levels found at 1 North End Avenue between October 16 and October 23, 2001 are as follows:

The 2,3,7,8 TEQs of the total

PCBs 0.004 picograms/m3 Chlorinated Dioxins 0.100 pg/m3 Chlorinated Furans 0.097 pa/m3 For a total TEQ of 0.201 pg/m3 for all chlorinated congeners

1 pg = 0.000000000001 gram

GLEN COVE, NY MIAMI; FL CHICAGO, IL ORANGE, CA 516 609-0009 305 86o-oio1 312 527-5526 714 282-2525

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