WTC environmental investigation report, Sep 2002

NYC 9/11 Public Portal Document

Final Technical Report of the Public Health Investigation Page 33 of 56 to be similar, and in some cases showed a similar profile in areas with elevated quartz (see Figures 13, 15, and 16). In general, where quartz was greater than 5%, calcite and portlandite were also present, but as smaller proportions of the dust. Gypsum, although often present with the other minerals, varied from being the most abundant to the least abundant in the dust.

4. Buildings Impacted by Asbestos, Synthetic Vitreous Fibers, and Crystalline Minerals

There was no clear pattern of which buildings were impacted by asbestos, SVF, and crystalline minerals. Figure 17 shows the approximate locations of the buildings and the level of contaminants in settled surface dust that were above or below the levels found in the comparison areas. The data are summarized and presented to indicate the indoor areas within a building with higher levels of a material in settled surface dust than was found in the comparison areas above 59th Street (Table 12). In this table, quartz was considered representative of the two other minerals associated with concrete, portlandite and calcite.

In 6 of the 29 buildings (approximately 21%) sampled in lower Manhattan, concentrations of these materials were not detected at levels higher than the levels in the comparison buildings above 59th Street. These six buildings tend to be among the buildings farthest from the World Trade Center and not located along what appear to be major streets or intersections. Map 17 shows the approximate locations of the buildings and the level of contaminants in settled surface dust that were above or below the levels found in the comparison areas.

Twenty-three buildings (approximately 79%) had levels of at least one of these materials in the dust at levels higher than the maximum found in the comparison buildings. Four of these buildings (buildings 4, 5, 6, and 9) contained all four materials above levels seen in the comparison areas above 59th Street in at least one indoor sample (Table 7). Seven of the 23 buildings were only impacted by SVF in indoor areas (buildings 13, 14, 17, 18, 25, 26, and 28). One building was only impacted by asbestos (building 11). The remaining 11 buildings were impacted by some combination of fibers and minerals. No clear pattern emerges in terms of which fibers or minerals occurred in the indoor dust of a building. Three of these building had only the two fiber types present (buildings 15, 24, and 27). One of these building had only the two minerals present (building 8).

The limited number of buildings sampled and the limited number of indoor locations that were sampled make it difficult to draw conclusions about the relationship of geographic location and the number of different materials found in the dust above the levels found in the comparison locations. However, buildings close to the World Trade Center tend to have a greater number of these materials found.

S. Significance of Minerals and Fibers in the Settled Surface Dust

The results previously discussed indicate minerals, asbestos, and

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