DOH/DEP asbestos fact sheet draft, 105 Duane Street

NYC 9/11 Public Portal Document 12/11/2001 17:06 FAX 212 353 8306 ATC ll 008

•,•1 D 5755 that the filters are centered and pulled flat without air 10.4.11 Apply vacuum to the flask and draw the mixture bubbles. Any irregularities on the filter surface requires the through the filter. discard of that filter. After the filter has been seated properly, 10.4.12 Discard the pipette. replace the funnel and reseal it with the tape. Return the 10.4.13 Disassemble the filtering unit and carefully re- flask to atmospheric pressure. move the sample filter with fine tweezers (7.11). Place the 10.4.5.2 If a glass filtration unit is used, place a 5 µm pore completed sample filter particle side up, into a prccleaned, size MCE (backing filter) on the glass frit surface. Wet the labeled, disposable, plastic petri dish (7.48) or other similar filter with particle-free water, and place an MCE or PC filter container. (50.22 µm pore size) on top of the backing filter. Apply a 10.4.14 In order to ensure that an optimally-loaded filter vacuum, ensuring that the filters are centered and pulled flat is obtained, it is recommended that filters be prepared from without air bubbles. Replace the filters if any irregularities several different aliquots of the dust suspension. For this are seen on the filter surface. Before filtration of each set of series of filters, it fs recommended that the volume of each sample aliquots, prepare a blank filter by filtration of 50 mL aliquot of the original suspension be a factor of five higher of particle-free water. If aliquots of the same sample are than the previous one. If the filters are prepared in order of filtered in order of increasing concentration, the glaze filtra- increasing aliquot volume, all of the filters for one sample tion unit need not be washed between filtration. After can be prepared using one plastic disposable filtration unit, completion of the filtration, do not allow the filtration funnel or without cleaning of glass filtration equipment between assembly to dry because contamination is then more difficult individual filtration. Before withdrawal of each aliquot from to remove. Wash any residual suspension from the filtration the sample, shake the suspension without additional assembly by holding It under a flow of water, then rub the sonification and allow to rest for 2 min. surface with a clean paper towel soaked in a detergent 10.4.15 There are many practical methods for drying solution. Repeat the cleaning operation, and then rinse two MCE filters. The following are two examples that can be used: times in particle-free water. (1) dry MCE filters for at least 12 h (over desiccant) in an 10.4.6 With the flask at atmospheric pressure, add 20 tnL airtight cabinet-type desiccator (7.21); (2) to shorten the of particle-free water into the funnel. Cover the filter funnel drying time (if desired), remove a plug of the damp filter and with its p)kstie cover if the disposable filtering unit is used attach it to a glass slide (7.19) as described in 12.1.2 and 10.4.7 Briefly hand shake (3 3) the capped bottle with the 12.1.3. Place the slide with a filter plug or filter plugs (up to sample suspension, then place it in a tabletop ultrasonic bath eight Plugs can be attached to one slide) on a bed of (7.12) and sonicate for 3.0 min. Maintain the water level in desiccant, in the desiccator for 1 h. the sonicator at the same height as the solution in sample 10.4.16 PC filters do not require lengthy drying before preparation, but shall be placed in a desiccator for at least 30 bottle. The ultrasonic bath shall be calibrated as described in min before preparation. 20.5. The ultrasonic bath must be operated at equilibrium 10.5 Prepare TEM specimens from small sections of each temperature After sonic ating, return the simple bottle to the dried filter using the appropriate direct transfer preparation work surface of the HEPA hood. Preparation steps 10.4.8 method. through 10.4.14 shall be carried out in this hood. 10.4.9 Shake the suspension lightly by hand for 3 s, then 11. Blanks let it rest for 2.0 min to allow large particles to settle to the 11.1 Prepare sample blanks that include both a process • bottom of the bottle or float to the surface. blank (50 mL of particle-free water) for each set of samples • 10.4.9 Estimate the amount of liquid to be withdrawn to analyzed and one unused flier from each new box of sample produce an adequate filter preparation. Experience has filters (MCE or PC) used In the laboratory. If glass filtering shown that a light staining of the filter surface will yield a units are used, prepare and analyze a process blank each time suitable preparation for analysis. Filter at least 1.0 mL, but the filtering unit leaned. Blanks will be considered no more than half the total volume. If after examination in is

contaminated, if after analysis, they are shown to contain the TEM, the smallest volume measured (1.0 mL) (7.13) more than 53 asbesboa structures per square millimetre. This yields an overloaded tatmple, then perform additional serial gully Corresponds to three or four altos structures dilutions of the suspension. If it is estimated that less than found in ten grid opening. The source of the contamination 1.0 mL of aolutian has to be filtered because of the density of must be found before any further analysis can be performed. the suspension, petfiorm a serial dilution. Rgect samples that were processed along with the contami- 10.4.9.1 If serial dilutions are required, repeat step 10.4.8 nated blanks and prepare new samples after the source of the before the serial dilution portion is taken. Do not re-sonicate contamination is found.

the original solution or any serial dilutions. The recom 11.2 Prepare field blanks which are included with sample mended Prveedtue fora serial dilution is to mix 10 mL of the sets in the same manner as the samples, to test for contami- sample solution with 90 mL of particle-free water In a clean nation during the sampling, shipping handling, and prepa- sample bottle to obtain a 1:10 serial dilution, Follow good ration steps of the method. laboratory practices when perfbrmin6 dilutions 10.4.10 Insert a new disposable pipette halfway into the 12. TEM

5pedme. Preparation

of

Mixed

Cellulose Ester

, sample suspension and withdraw a portion Avoid pipetting (MCE) Palters

any of the large floating or settled particles. Uncover the filter funnel and dispense the mixture from the pipette into the Norte I

-Use of either

the acetone

or the

diamethylformamlde.

acetic acid

method

ac eptabie. is

wade in the funnel. 12.1

Acemne Fusint

Method

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