VOC sampling locations table for Ground Zero area, Jan 2002

NYC 9/11 Public Portal Document

simple model to predict body burden increase, and it was fotmd that the exposure of the WTC workers suggests that their body burden could rise up to 10% above current average background. These cancer and non-cancer results resulting from dioxin exposure were evaluated as not significant risks over average background risks for this class of compounds.

VI.b. Data on Indoor Environments

EPA Region 2 is currently conducting extensive monitoring and clean-ups of indoor residences. Much of the information on this effort can be seen on the following website:www.epa.gov/wtc. Part of their effort is to also evaluate background conditions, so that measurements can be compared to this background. It is expected that this effort will provide data from which EPA can conduct further health risk assessments. Also, EPA’s Region 2 has been collecting data from various public and private monitoring efforts, and have provided a tabular summary of their preliminary compilation for use in this report (table provided by M. Maddaloni, Region 2, to M. Lorber, EPA Washington, August 18, 2002). The Agency for Toxic Substances and Disease Control (ATSDR) has conducted the only systematic study of the residential environment to date, and the results of their efforts are summarized below. Other summaries are provided below only for the systematic efforts that have been conducted or are underway.

Vl.b.l. ATSDR Study on Apartments in Lower Manhattan The New York City Department of Health and Mental Hygiene (NYCDOHMH) and ATSDR have released the Final Report of the Public Health Investigation to Assess Potential Exposures to Airborne and Settled Surface Dust in Residential Ares of Lower Manhattan (NYCDOHMH/ATSDR, 2002). From November 4 through December 11, 2001, environmental samples were collected in and around 30 residential buildings in lower Manhattan. In addition, four buildings above 59th Street were sampled and used as a comparison area for this investigation.

Bulk dust samples were collected both indoors and on outdoor surfaces and analyzed for the presence of asbestos by both the PLM (polarized light microscopy) and TEM methods. PLM can distinguish between fiber types in a bulk sample by their unique appearance and color when viewed under different wavelengths of light. Asbestos was detected in settled indoor dust in 10 out of 57 (18%) residential units sampled, with the positive samples showing a maximum of 1.5% asbestos in dust. By comparison no asbestos was detectable in dust samples collected in the 5 comparison residences. In outdoor dust collected at Lower Manhattan properties, asbestos was detected in 6 of 14 (43%) samples, with a maximum asbestos concentration in dust of 3.4%.

Importantly, airborne fibers were not detected above background levels (stated as 0.003 fZcc — fibers meeting criteria for optical visibility) in any of the indoor air samples collected at the 57 residences in Lower Manhattan. Some understanding of the protocol design is needed to interpret the air sampling data. All air filter samples were analyzed first using PCM to determine if fibrous materials were present. If the PCM count (which does not distinguish fiber type) exceeded a 0.003 free level identified as background (using the upper Manhattan measurements), then a TEM analysis for asbestos fibers was performed. Airborne asbestos fibers (meeting equivalent criteria for optical visibility) were not detectable in any TEM analyses (generally <

DRAFT-DO NOT QUOTE OR CITE 128 October 2002

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