VOC sampling locations table for Ground Zero area, Jan 2002

NYC 9/11 Public Portal Document

Metals

Lead. Persons caught in the initial WTC-related dust cloud experienced brief exposures to high levels of lead (Pb), based on analyses ofdeposited dust samples. In late September 2001, air lead concentrations at the WTCperimeter sites reached levels above 1.5 pg/m^ on some days. However, the air lead levels averaged over 90 days (late September - late November) did not exceed the EPA National Ambient Air Quality Standard (NAAQS) of 1.5 pg/m^ averaged over a 90-day period. After mid-October, air lead at all sites in lower Manhattan outside WTC Ground Zero dropped to levels more comparable with background concentrations typical of NYC and other northeastern United States urban areas. On the basis of ambient air and dust data, there is little indication of any substantial health risks being associated with lead exposures of the general population in lower Manhattan areas around the WTC site.

On several days in late September 2001, 24-hour Pb concentrations at the WTC Ground Zero perimeter sites exceeded 1.5 pg/m’. This level was again approached or exceeded at one or another WTC perimeter site during early October (10/3 -10/5). However, airborne Pb rapidly decreased with distance from the WTC perimeter sites, with Pb concentrations on the same days when Pb levels were elevated at Ground Zero being substantially lower at several locations within 3-10 blocks from the WTC (i.e., mostly within the 0.11 to 0.63 pg/m’ range of 24-hour Pb levels observed at some Manhattan and Brooklyn sites during the 199O's). After mid-October, 2001 Pb readings for all WTC perimeter sites and other lower Manhattan sites remained below 1.5 pg/m’, with few even exceeding 0.5 pg/m\

Lead concentrations in bulk dust samples taken close to the WTC within days after September 11 ranged up to 625 pg/g (ppm). This level is well below street dust Pb levels on or near heavily traveled roadways prior to phase-down of Pb in gasoline in the late 197O's, which often were well in excess of 1000 - 2000 ppm, and it compares well with the 500 - 1000 ppm street dust or soil lead levels found in northeastern or midwestem U.S. urban areas well into the 1990s.

In general, the observed ambient air lead levels did not appear to pose increased health risks for the general public. However, susceptible persons (especially any pregnant women) who may have experienced extended exposures to elevated Pb levels within WTC Ground Zero work areas while not wearing appropriate respiratory protective gear or who were exposed to indoor WTC-derived dusts with high Pb loadings could possibly be at increased risk for chronic health effects. Evaluation of blood lead levels and pertinent medical records for any pregnant women exposed at Ground Zero or in its immediate vicinity during late September/early October could provide useful further data by which to assess any such possible health risks associated with WTC-generated lead emissions.

Chromium. Samples evaluatedfor total chromium at Ground Zero and at sites surrounding Ground Zero never exceeded the OSHA PEL of 1 mg/m^ or the ATSDR Intermediate Minimum Risk Level (MRL) for chromium VIparticulates of 1.0 pg/m^. On the basis of the samples evaluated, exposures to chromium were not likely to cause any adverse health effects.

DRAFT-DO NOT QUOTE OR CITE 5 October 2002

NYC-WTC_000149086