EPA interim final report on WTC background study, April 2003

NYC 9/11 Public Portal Document

Revised May 14,2003 Backgroimd concentrations that were derived based on the analytical results from the samples collected in this study. The concentrations listed in the table represent the 95% upper confidence limit (UCL) on the arithmetic mean.

Settled Dust Compound Air Bulk Dust Porous Hard Surface Surface Asbestos iiii n/a (<1%) 6,192 s/cm’*

ililil ■■ . ' - •

Asbestos - PCM 0.0023 s/cc’^ y: • 1 - ,

Asbestos - TEM OJ as24 s/cc’^ ■; • ' AHERA • . : 3 Asbestos - TEM as24 s/cc”^ O.i By PCMe IB MMVF Ojaw s/cc’^ n/a (<1%) 52 s/cm^^ Lead 0.03 pg/m’"^ 186mg/kg^ 1.98 pg/fV^ 1.78 pg/tf’^ Dioxin IBiBSil 0.693 ng/m^^ PAH ifclSlBi (<290n/apg/m^) ' Cl Y"i‘ ’‘-”7

Alpha-quartz 61.9 pg/m^^ 3.66 79.6 pg/ft^ (w/o max. value) (7.8 pgZm») Calcite 9.3 3.41 132.3 T—TT V / '• , Cristobalite . 9.3 4.69 103.7 >T Gypsum 9.3 2.33 49.9 B f Portlandite 9.3 //g/m^^ 4.69%^ 99.8 Tridymite 9.3 //g/m^^ 4.69%^ 99.8pg/ff’Z Total Dust 14.4 mg/fV^

n/a - indicates that a upper confidence limit could not be calculated, value in parenthesis indicates that the value is less than the detection limit italics - indicates a theoretical UCL due to all data being below the detection limit T - indicates the total data set was used R - indicates only the residential data set was used

WORLD TRADE CENTER BACKGROUND STUDY 4

NYC-WTC_000145879