EPA interim final report on WTC background study, April 2003

NYC 9/11 Public Portal Document

2.4 Project Team/Responsibilities EPA Region 2 staff provided overall management and oversight of the project, identified participant buildings, obtained access to participant buildings and implemented the field sampling portion of the project with the assistance of EPA’s contractor, TRC Solutions Inc. (TRC). All communication regarding site work activities, work scheduling, difficulties encountered, deviations from the QAPP/sampling plan, and project progress was addressed by the EPA Project Officer on a daily basis. TRC provided deliverables and services associated with the sampling operations for this project.

2.5 Data Usage The data generated fi-om this Study were used to establish baseline information on residential contaminant levels found in typical NYC dwellings.

The analytical data collected were evaluated first for individual apartments and common areas and second, cumulatively, which consisted of combining data sets for residential dwellings and common areas (i.e., asbestos wipe sample data for residential dwellings, common areas and a combined data set for residential and common spaces) to derive background concentrations representative for Manhattan.

The confidential evaluation prepared for individual apartments compared the reported results for each sample to the health-based benchmarks developed in the peer review draft of the "World Trade Center Indoor Air Assessment: Selecting Contaminants of Potential Concern and Setting Health-Based Benchmarks" document. The analytical data for each analyte were presented in tabular format for each apartment with text that explains the reported results. Any sampling that resulted in detections exceeding the health-based benchmarks was discussed in a detailed letter and orally when requested by the resident or owner.

Cumulatively, the data were statistically evaluated to provide descriptive statistics for each analyte and sample matrix. For each analyte, a recommended concentration that is representative of background concentrations under a given set of assumptions, for upper Manhattan, is discussed in Section 6.0 and presented in Table 8-1.

Results from this Study cannot account for the variability with indoor environments in general (e.g., cross contamination from outdoor environments to indoor environments, way of life, and level of cleanliness). The measurements are limited to each specific apartment or common area sampled at that specific time the samples were collected. The selection of sample point locations within each unit were decided in the field, on a case-by-case basis and do not represent the entire apartment or common area sampled.

WORLD TRADE CENTER BACKGROUND STUDY 8

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