Document header for 61 Broadway records, 2002

NYC 9/11 Public Portal Document

FROM : FAX1 w4NO. Jan. 08 2000 1033PM PIG 1/lilI .&StU.Wá W .%I I1 Vs.V BIII•V%W$X

t.EAD b>r Plains A&V t Rod 7oi2,isle __dated 16 August 1J94 Pscm_3of7

NOTE: If the concentration (M) of any of the following is expeected to exceed the lead ooncentnation(M)by 10-fold or more. add I rnL I M NgDTA to each flask before dilution to volume: C -. POQ I -. F CH,COO-. if Car- or SQ, - are present In 104eld or greater excess, make ail standards and samples I % (wlw) In X133.

CALi®RATION AND QUAL" CONTROL: 11. Prepare a series of wolfing standards covering the range 0.25 to 20 pg/mL Po (2.5 to 200 yo Pb per sample).

a. Add aliquots of calibration stock solution to 100•mLvalumetriicfissiaa. Dilute to volume with 10% I4NQ' . Srere The werltirrp standards In polyethylene buttles and prepare trash weekly. b. Analyze the working standards together with The blanks and samples (ateps 14 and 15). o. Prepare a otlibratlon graph of abso,bgnoe vs. solution concentration (pg/mL). 12. Aspirate a standard for every 10 samples to cheek for instrument drift. 13. Check recoveries with at least one spiked media blank per 10 samples. Use method of standard additions to check for intettsrencaw. occasionally

M UREMEt4T: 14. Sept apsctrophotometer as apeoilied by the manufacturer end to Conditions on page 7002.1. NOTE: An alternate wavelength to 217.0 nm [8J. Analyses at 217.0 nm have slightly greater sensitivity, but poorer signal-to-noise ratio Dompared to 283.3 nm. Also, non-atomic absorption is stgnillcantky greater at 217.0 MM. mat4ng the use of k r Hs continuum, or Zeeman background correction mandatory at that wavelength, 16. Aspirate standeRq, samples, and blaniq- Record absorbance readings. NOTE: if the absorbance valves for the samples are above the linear range of the standards, dilute with 10% i4Nq, reenalyue, and apply the appropriate dilution factor in the calculations,

CALCULATIONS: 16. Using the measured ebsoibences, calculate the correappndinQ oorr0sntrattons sample, C,. and average media blank, Q, from the culibr*tlon graph. (pg!mL) ofload in the 17. the solution volumes (rnL) of the sample. ' and Using

blanks, \, calculate the concentration. C (mg/n1), of lead bh the air volume sampled. V (1_): media

NOTE: p01mL ■ mg/m

VALUATION OF METHOD: Method 5341 191 issued 24, 1076, and vaabated overtha 0.13 0,4 was

on

October

range

to

a mg%r

180-L

air

sample,

using

generated

atmospheres

of le ered

nkhebe [1].

Recovery In the

to range 18

pg 72

Pb per

sample

was

08%,

and

collection

efficiency

0.&m

of

mbted

eater cellulose

fi lters

(Millipore

A) Typ

was

100%

forthe

aerosols.

Subsequent

studies on

anetytical

recovery

of 200 pg

Pb

pereampte

the

gave

following

results

[2,43:

ouu

t Ms+W

arnn1s!

O

NAPA

FW*

Udwn

NYC-WTC 000105594