Special Investigative Audit #14 Draft, WTC Site, Nov 2001

NYC 9/11 Public Portal Document

Metals

The NYC Response database include results for metals in air, water, bulk dust, sludge, and sediment samples. The lead, cadmium, chromium, arsenic, beryllium, and mercury results in air samples are discussed. To date (November 19"'), metals in air concentrations have been reported for samples through October 18`h. Of those described above, lead was the most frequently detected metal. The lead results 'from five (5) Lower Manhattan locations are presented below in Table 15 and the following figures. Lead was detected at a maximum of 5.4 ug/m3 on September 23`d at the WTC Building 5 SW site. 'Not detected' results were also reported for October 2nd samples without sample begin dates or signs and are therefore omitted in the table and graph.

At three (3) of the five (5) sites listed in Table 15, the linear fit lines and correlation coefficient calculations indicate a steady decrease in lead air concentrations. The correlation coefficients comparing concentration with time (day) is -0.9459 for Location A, -0.8780 for Location B, and -0.6386 for the WTC Building 5 site. The WTC Building 5 SW lead concentrations have been fairly steady over the past 4 sampling dates. The negative correlation coefficient indicates an inverse trend, i.e., as days increase, the concentration decreases. The trends at Location C and D are much less well defined. At Location C, the correlation coefficient of concentration vs time is 0.0148. At Location D, the correlation coefficient is 0.2136. Correlation coefficients approaching zero (0) indicate no similarity.

Cadmium was detected in only one (1) of the listed samples from the WTC-Building 5 site at 0.2 ug/m3. The only other detected cadmium in air that we have found was from Location E-Liberty St & South End Ave, at 0.13 ug/m3 on Oct 11, 2001. Chromium was detected at several sites ranging from 0.24 to 0.38 ug/m3. Arsenic was also detected at the Location A-Barclay & West Broadway site on September 27`h and October 4U' at 0.053 and 0.049 ug/m3, respectively. Beryllium and mercury were not detected in any of the air samples with detection limits for beryllium listed at approximately 0.05 ug/m3 in most of the samples.

Table 15. Lead in Air Units: ug/m3

18-Sept na 1.9 na na na 23-Sept 4.3 1.7 0.69 0.38 5.4

27-Sept 2.8 0.69 <0.043 <0.042 1.1

4-Oct 1.4 0.26 0.079 0.098 0.42

8-Oct 0.55 0.32 0.51 0.95 0.73

11-Oct 0.49 0.23 <0.05 0.093 0.48

15-Oct 0.13 0.28 0.056 0.47 1.1

18-Oct 0.065 0.16 0.56 0.32 0.66

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