NYC-WTC_000199730

NYC 9/11 Public Portal Document

NYC/ER (Oct 11)-Metals o Ten samples collected. o All metals were either not detected or were below applicable E PA Removal Action level guidelines, OSHA PELs, and the NAAQS for lead. o Note: Further QA/QC review of chromium in air analytical data generated in the past for the WTC monitoring effort, including the results for Oct 11"’, has revealed that chromium is not present in these samples. This includes the results for samples collected on Sep 16"’, Sep 23’", Sep 27‘", Oct 2”", and Oct 4‘".

NYC/ER (Oct 8)-PCBs o Trace amounts detected in 4 of 10 samples well below levels of concern. o 6 samples did not detect any PCBs. o All levels are below the EPA Removal Action level guidelines. NYC / ER (Oct 2) - Silicates

o All 10 samples did not detect any silicates.

NYC / ER (Oct 4) - Silicates

o All 10 samples did not detect any silicates.

NYC / ER (Oct 17) - Particulate Monitoring (PMjj) o Pace University (Site 1) - 24-hr average concentration for this period was 15.50 ug/m^. o Manhattan Boro Community College (Site 2) - 24-hour average concentration for this period was 6.52 ug/m\ o Coast Guard Building - Battery Park (Site 3) - 24-hour average concentrations for this period was 5.18 ug/m^. o All readings below the National Ambient Air Quality Standard for PM. , (65 ug/mQ.

NYC / ER (Oct 18) - Particulate Monitoring (Dataram ) o Particulate levels noted at three locations (Stations L, N, R ) were below the OSHA TWA. o Instruments operated between 8 to 9.5 hours. o Station L values ranged from 0 to 37.4 ug/m3 with an average of 17.8 ug/m3. o Station N values ranged from 4.4 to 23.9 ug/m3 with an average of 8.8 ug/m3. o Station R values ranged from 7.2 to 71.2 ug/m3 with an average of 10.9 ug/m3.

NYC / ER (Oct 18) - Volatile organics (TAGA) o These samples, and all those previously collected for VOC analysis via GC/MS in the TAGA, represent grabs collected over a period of a few minutes. The analytical results should be view ed in that context. o Benzene exceeded O SHA TWA PEL (1 ppm) at one location on the debr is pile in the plume at ground level. NOTE: benzene PEL was previously identified as 0.5 ppm. This concentration actually represents an OSHA action level u sed to trigger certain monitoring requirements. o Overall VOC levels in the debris pile improved significantly from previous results.

CITY_21MC100_002458742

NYC-WTC_000199731