NYC-WTC_000199886

NYC 9/11 Public Portal Document

Polychlorinated Biphenyls (PCBs) (December 6, 8, and 11, 2001)

Eight air samples were analyzed from inside and outside PS 234 on December 6, 8 and 11, 2001. PCBs were not detected in any of the 8 samples collected on any of the three days.

Polycyclic Aromatic Hydrocarbons (PAHs) (December 6, 8, and 11. 2001)

The only PAH compound detected in the samples from outside the school was naphthalene, at concentrations from below the detection limit to 0.32 ug/m^, while inside the school, naphthalene (ND to 0.69 ug/m’), 1-methylnaphthalene (ND to 0.49 ug/m’), and 2-methylnaphthalene (ND to 0.92 ug/m’) were detected. Naphthalene is the major constituent of mothballs, and all three compounds are found in cigarette smoke. The detected concentrations are all within documented urban background levels. While there are no relevant standards for these compounds, the USEPA Region 9 preliminary remediation goal (PRO) for naphthalene in air, adjusted for a school exposure scenario, is 8.7 ug/m’ for naphthalene. There is no PRG for either 1-methylnaphthalene or 2- methylnaphthalene. Naphthalene concentrations in all samples were well below the adjusted Region 9 PRG.

Dioxin and Dibenzofurans (December 6, 9, and 12,2001)

Trace levels of dioxins were detected in all the indoor and outdoor samples collected on all three days. Reported TCDD Equivalents (a measure of the toxicity of the dioxin and dibenzofuran constituents detected in the sample expressed in terms of the toxicity of 2,3,7,8-tetrachloro-dibenzo-p-dioxin, the most potent of the dioxin isomers) were as follows (in picograms per cubic meter, pg/m’):

Date oof Concen^rq^ion Outdoor Ccncentration

December 6 0.0078-0.028 pg/m^ 0.038-0.073 pg/m’ December 9 0.0079-0.022 pg/m’ 0.028-0.037 pg/m’ December 12 0.0013-0.0035 pg/m^ 0.0014-0.0022 pg/m’

There are no relevant standards for dioxins in air in a school setting. USEPA is utilizing a screening level of 160 pg/m’, assuming a one-year exposure, and 5.4 pg/m\ assuming a 30-year exposure. The USEPA Region 9 preliminary remediation goal (PRO) for dioxin in air adjusted for a school exposure scenario is 0.126 pg/m’. The dioxin levels were all well below any of these screening levels.

Mercury (December 7,9, and 12, 2001)

Mercury was not detected in any of 8 samples collected on December 7, 9, and 12, 2001 above the level detected in the method blank.

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NYC-WTC_000199890