c/EPA
           United States
           Environmental Protection
           Agency
           Research and Development
                 Atmospheric Research and Exposure
                 Assessment Laboratory
                 Research Triangle Park, NIC 27711
April 1995
                                    EPA600/R-95/052
Standard Operating Procedure
for Solubilization of Lead on
Dust Wipes by Hotplate Acid
Digestion

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       STANDARD OPERATING PROCEDURE
 FOR SOLUBILIZATION  OF LEAD ON DUST WIPES
         BY HOTPLATE ACID DIGESTION
                    Prepared For:

                 Ms. Sharon L. Harper
               Work Assignment Manager
  Atmospheric Research and Exposure Assessment Laboratory
           U.S. Environmental Protection Agency
           Research Triangle Park, NC 27711
             EPA Contract No. 68-D1-0009
RTI Project Nos. 91U-5960-126, 91U-6960-231, 91U-6970-260

                     Prepared By:

D. A. Binstock, E. D. Estes, E. E. Williams, and W. F. Gutknecht
Center for Environmental Measurements and Quality Assurance
               Research Triangle Institute
         Research Triangle Park, NC  27709-2194

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                               DISCLAIMER
      The information in this document has been funded wholly or in part by the
United States Environmental Protection Agency (U.S. EPA) under EPA  Contract No.
68-D1-0009 to the Research Triangle Institute (RTI). It has been subjected to the
Agency's peer and administrative review, and it has been approved for publication as
an EPA  document.   Mention of trade names or commercial  products  does not
constitute endorsement or recommendation for use.

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                          ACKNOWLEDGMENTS

     This document was prepared under the direction of Ms. Sharon L. Harper,
Atmospheric Research  and Exposure  Assessment  Laboratory (AREAL),  U.S.
Environmental Protection Agency, Research Triangle Park, NC.
                                   in

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                         Table of Contents

Section                                                      Page

Disclaimer	ii
Acknowledgments  	iii
List of Tables	v

1.0  PRINCIPLE AND APPLICABILITY	   1
     1.1   SCOPE AND APPLICATION 	   1
     1.2   SUMMARY OF METHOD	   1

2.0  APPARATUS	   8
     2.1   SAMPLING  	   8
     2.2   EXTRACTION	   9
     2.3   PROTECTIVE EQUIPMENT	11

3.0  PROCEDURES	  13
     3.1   COLLECTION OF MATERIAL  	  13
     3.2   QUALITY CONTROL SAMPLES	  14
     3.3   EXTRACTION PROCEDURE 	15
     3.4   DATA PROCESSING	17

4.0  QUALITY CONTROL  	  18
     4.1   SAMPLE COLLECTION  	18
     4.2   WIPE EXTRACTION  	18
     4.3   QUALITY CONTROL SAMPLES	18

5.0  SAFETY	  20
     5.1   COLLECTION	:	20
     5.2   ANALYSIS	  20

6.0  WASTE DISPOSAL	  21
     6.1   PROTECTIVE CLOTHING	21
     6.2   WASH WATER	21
     6.3   EXCESS DUST WIPE SAMPLES 	21
     6.4   SOLUTION WASTE	21

7.0  CORRECTIVE ACTION 	  22

8.0  REFERENCES  	  23
                               IV

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                                List of Tables

Table                                                                   Page

 1     Wipe Sampling Methods	  2

 2     Dust Wipe Hotplate Digestion - K-Mart Little Ones Baby Wash Cloths®
      Spiked With 0.100 g Reference Material	  6

 3     Dust Wipe Hotplate Digestion - Wash'n Dri Moist Disposable Towelettes"
      Spiked with  0.100 g Reference Material	  6

 4     Dust Wipe Hotplate Digestion - Nuclepore" Filters
      Spiked with  0.100 g Reference Materials  	  7
                                      v

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1.0   PRINCIPLE AND APPLICABILITY
1.1   SCOPE AND APPLICATION
      The  adverse  health effects resulting  from exposure  of young children to
environmental lead have received increasing attention in recent years.  Studies have
shown that chronic exposure even to low levels of lead can result in impairment of the
central nervous system, mental retardation, and behavioral disorders.1'2  Although
young children are at the greatest risk, adults may suffer harmful effects as well.3
      As a result of the growing concern about these  adverse health effects, the
identification and assessment of hazards from lead-based  paint (LBP)  and LBP-
containing dust and soil  have become critical  environmental issues. To quantify the
magnitude  of these hazards and to develop  and implement strategies  for their
reduction, methods for measuring lead in paint, soil, and dust must be developed and
validated.
      Measuring lead in dust involves collecting the dust, in most cases extracting the
lead from the dust, and finally instrumentally measuring the extracted lead.  Current
methods of dust collection include vacuuming,4'5 which  may result in the collection
of bulk dust or dust on filters, and surface collection using a wipe. A  large number
of wipe methods have been developed, several of which  are described in Table  1.
Protocols  for evaluating wipes  have  been  published,  including the  protocol by
Chavalitnikul and Levin.19  Procedures have been developed  for measuring lead  in
dust20'21 and lead in  dust on air filters.22'23  This standard operating procedure (SOP)
describes a hotplate acid digestion of lead in dust collected on wipes.  This procedure
is based on  a method  provided by Ms. Harriotte Hurley,  formerly of  Azimuth
Laboratories, Charleston, SC.24

1.2   SUMMARY OF METHOD
1.2.1  Sampling and Analysis
      The dust wipe sample collection procedures vary  considerably (See Table 1).
The basis of each method, however, is to manually move the  wipe material (natural
or synthetic fabric, paper, etc.) across a fixed area of surface. The material may or
                                      1

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TABLE 1. WIPE SAMPLING METHODS
Method/ .
Researcher
ASTM
ES-30-94






Georgia
Tech






HUD







Kennedy-
Krieger
(Farfel)





Lepow
(1974)
Surface
Type
Hard (floors.
windows)






Hard (floors.
windows)






Hard (floors,
windows)






Hard







Hard

Wipe Matrix

Disposable
towelette
moistened with
wetting agent




Little Ones Baby
Wash Cloths"
(K-Mart)





Commercial non-
alcohol wipes






Non-alcohol
wipes






Preweighed
adhesive labels
Area

Template 30
cm x 30 cm
(12" x 12")
measured
area



Measured
area






Template
12" x 12",
or measured
area




Template
12" x 12",
or measured
area




—

Sampling Procedure

• Wipe with "S" motion
L-R, F-B
• Fold wipe
• Repeat with "S" motion
F-B, L-R,
• Fold wipe
• Repeat with "S" motion
L «• R, F - B
• Wipe with "S" motion
F - B, L « R
• Fold wipe
• Repeat with "S" motion
F-H-B, L-R
• Fold wipe
• Repeat with "S" motion
L«.R, F-B
• Wipe with "S" motion
L «• R, F - B,
• Fold wipe inside
• Wipe with "S" motion
90° to first wipe
• Fold wipe
• Repeat with "S" motion
L «• R, F - B
• Wipe with "S" motion
L«-R, F-B,
• Fold wipe inside
• Repeat with "S" motion
F«B, L-R
• Fold wipe
• Repeat with "S" motion
L~R, F-B
—

Container

Hard-walled
container
recommended





Centrifuge
tube (50 mL)






Polypropylene
tube (50 mL)






Ziploc bags







—

Units

//g/cm2







//g/ft2







jug/ft2







A/g/ft2







PQ/9

Reference

6







7







8







9







10

                                                          (continued)

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                                             TABLE 1. (Continued)
Method/
Researcher
Rabinowitz


LWW







NIOSH










Stark

State of
MA


State of NC



Surface
Type
Hard


Hard







Hard










Hard

Hard (floors,
windows)


Hard (floors,
windows)


Wipe Matrix

Preweighed filter
paper (Whatman
541)
3 polyethylene
filters
(preweighed) 3.8
cm x 6.35 cm




• Gauze 2" x 2"
wetted with 1-
2 mL distilled
water*
• Wash'n Dri®
(Canaan
Products, Inc.)
wipes
(individually
wrapped) or
equivalent
Prewetted cotton
gauze
Individually
wrapped alcohol
wipes (Triad
Medical, Inc.)
Johnson &
Johnson Baby
Wipes

Area

930 cm2


Template
27.3 cm x 4
cm





1 0 cm x 10
cm
disposable
template







—

Template
1ft2


Template 1
ft2 or
measured
area
Sampling Procedure

	


• Wipe within template with
filter 1 (moistened with
Type I water)
• Wipe within template with
filter 2 (moistened with
Type I water)*
• Wipe within template with
filter 3 (dry)
• Wipe with "S" motion 3-4
vertical strokes
• Fold wipe inside
• Wipe with "S" motion 3-4
horizontal strokes
• Fold wipe inside
• Wipe with "S" motion 3-4
vertical strokes



—

Wipe area once L -» R



• Wipe with "S" motion
• Wipe with "S" motion 90°
to first pass

Container

Resealable
polyethylene
bags
Aluminum
pouch inside
of plastic bag





Ziploc bag










...

Plastic tube



Ziploc bag



Units

A/g/wipe


^g/ft2
fjg/a






A/g/ft2
(mg/m2)









A/g/g

A*g/ft2



A/g/ft2



Reference

11


12







13
14









15

16



17



(A)
                                                                                                    (continued)

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                                         TABLE 1.  (Continued)
Method/
Researcher
Vostal







Surface
Type
Hard
(uncarpeted)






Wipe Matrix
Disposable paper
towel (14 cm x
20cm)
moistened with
20% denatured
alcohol or 1 :1 50
benzalkonium
chloride
Area
Template
1ft2






Sampling Procedure
	







Container
	







Units
^g/ft2







. Reference
18







LEGEND:

  L «» R = Left to Right, Right to Left in Overlapping "S" Motion
  F -» B = Front to Back (Top to Bottom)
  * American Society for Testing and Materials (ASTM) Type 1 water: resistance
16.67 megaohm-cm

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may not be pretreated with liquid solubilization or wetting agents (detergents).  The
wipe is folded to enclose the collected dust and may be used to wipe a second or
even third time before being placed in a labelled container or bag.
      Using the digestion method described in this  SOP, the loaded dust wipe is
placed into  a 250-mL beaker  and  digested  using  30% hydrogen peroxide  and
concentrated nitric acid.  The digestion mixture is quantitatively transferred to a
50-mL polyethylene centrifuge tube, and the tube is filled to the mark with doubly
deionized water.  The residue is separated from the supernatant by centrifugation or
simply by permitting it to settle overnight. The supernatant is analyzed for lead by
inductively coupled argon plasma (ICP) emission spectrometry, using the 220.35-nm
emission  line and  the  optimum instrumental  conditions  recommended  by the
manufacturer.25

1.2.2 Precision and Bias
      As noted in Table 1, many different types of wipes are  commercially available.
In this study, three types of wipes  were selected for testing the wipe extraction
procedure because (1) they were representative of the various types in use and (2)
they were used in methods provided by Federal organizations or proposed for use in
federal programs.   Included were a baby wipe used in a procedure published in the
U.S. Department of Housing  and Urban Development's (HUD's) Guidelines for the
Evaluation and Control of Lead-Based Paint Hazards in Housing,8 a wipe used in a
procedure proposed by the  National  Institute for Occupational Safety and Health
(NIOSH),13 and a Nuclepore  filter used in a procedure known as the Lioy-Weisel-
Wainman  (LWW)  method proposed  for use in  the EPA National  Human Exposure
Assessment Survey (NHEXAS).12-26
      The three types of  dust wipes (Little Ones Baby Wash  Cloths",7'27 Wash'n Dri
Moist Disposable Towelettes ,13'28 and Nuclepore"  filters12-29) were spiked  with
standard reference materials (SRMs) and  method evaluation materials (MEMs) and
digested using the hotplate procedure summarized in Section 1.2.1.  The reference
materials used included National Institute of Standards and Technology (NIST) SRM

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1579, powdered lead-base paint; NIST SRM 2704, Buffalo River sediment; and two
dust MEMs from the American Industrial Hygiene Association's Environmental Lead
Proficiency Analytical (ELPAT) program.30
      Accuracy as percent bias and precision as relative standard deviation (RSD)
were determined and are presented in Tables 2 through 4.31  Accuracy as percent bias
ranged from -8.7% to  +3.7% and precision as RSD ranged from 2.54% to 11.7%.
The average bias was -2.9%  and the pooled RSD was 7.8%.
      TABLE 2.   Dust Wipe Hotplate Digestion - K-Mart Little Ones Baby Wash
                       "
                 Cloths  Spiked with  0.100 g Reference Material (fjglg Except
                 Where Noted)
Sample

NIST 1579
NIST 2704
ELPAT 3D2
ELPAT 3D4
Reference Value

11.87 ± 0.04%
161 ± 17
551 ± 55a
2210 ± 401a
Mean Value ± SD
(N = 3)
11.9 ± 0.32%
147 ± 14.1
516 ± 27.5
2150 ± 247
Accuracy
as % Bias
0
-8.7
-6.8
-2.7
RSD
%
2.69
9.60
5.33
11.5
      a ELPAT program mean value of 34 reference laboratories.30
      TableS.    Dust Wipe Hotplate  Digestion - Wash'n  Dri Moist Disposable
                 Towelettes Spiked with 0.100 g Reference Material (//g/g Except
                 Where Noted)
Sample

NIST 1579
NIST 2704
ELPAT 3D2
ELPAT 3D4
Reference
Value
11.87 ± 0.04%
161 ± 17
551 ± 55a
2210 ± 401a
Mean Value ± SD
(N = 3)
11.5 ± 0.35%
167 ± 19.5
537 ± 13.6
2110 ± 222
Accuracy
as % Bias
-3.4
3.7
-2.5
-4.5
RSD
%
3.04
11.7
2.54
10.5
       ELPAT program mean value of 34 reference laboratories.30

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                                                    ®
TAEJLE 4.    Dust Wipe Hotplate Digestion -  Nuclepore" Filters Spiked with
            0.100 g Reference Material (//g/g Except Where Noted)
Sample

NIST 1579
NIST 2704
ELPAT 3D3
ELPAT 3D2
Reference
Value
1 1 .87 ± 0.04%
161 ± 17
551 ± 55a
221 Ob ± 401 a
Mean Value ± SD
(N = 3)
10.9 ± 1.11%
162 ± 6.11
543 ± 45.1
2190 ± 75.8
Accuracy
as % Bias
-8.4
0.6
-1.4
-0.9
RSD
%
10.2
3.77
8.30
3.46
 ELPAT program mean value of 34 reference laboratories.30

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2.0   APPARATUS

      The apparatus used for sampling and analysis of the dust wipes is described
below.

      NOTE:   Before  use,  all  labware  should  be scrupulously  cleaned.   The
               recommended procedure is:

            1.  Wash with hot laboratory detergent in  water or ultrasonicate 10
               minutes with laboratory detergent in water.
            2.  Rinse and then soak a minimum of 1 hour in 50%  volume/volume
               (v/v) nitric acid.
            3.  Rinse three times with double deionized water and air dry or oven
               dryat105°C.

2.1   SAMPLING
      The dust collection  procedures referenced in this SOP use the materials and

apparatus as follows:

      2.1.1  HUD Method  Using Baby Wipe7'27
          2.1.1.1  Disposable  baby  wipe  (Little  Ones  Baby Wash  Cloths"  or
                  equivalent).

          2.1.1.2 Gloves, latex, powder-free,  disposable (Fisher Scientific Catalog
                  No. 11-393-53 or equivalent).

          2.1.1.3 Centrifuge  tubes:    50-mL disposable  polypropylene (Fisher
                  Scientific Catalog No. 05-526B or equivalent).

          2.1.1.4 Template:   either  masking tape or reusable made of laminated
                  paper, metal, or plastic; typically 1 ft2 (929 cm2) to enclose the
                  area to be wiped.
      2.1.2 NIOSH Method Using Gauze or Hand Wipe13'28

          2.1.2.1  Gauze pads, 2"  x 2" sterile cotton (Curity, Johnson & Johnson,
                  or equivalent), or Wash'n  Dri Moist Disposable Towelettes  or
                  equivalent.

          2.1.2.2  Bags, plastic, scalable (for example, with attached wire, tape, or
                  zip-type seal); (Ziploc 1-quart freezer bags or equivalent).

          2.1.2.3  Gloves, latex, powder-free, disposable (Fisher Scientific  -  see
                  Section 2.1.1.2 or equivalent).
                                      8

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          2.1.2.4 Template, plastic,  10 cm x  10 cm or other  standard  size to
                  enclose the area to be wiped.

          2.1.2.5 Water, distilled, ASTM Type 1, in plastic squeeze bottle.
      2.1.3 LWW Method Using Nuclepore® Filter12'29

          2.1.3.1  Nuclepore" filter preweighed and stored in folded aluminum foil
                  pouch (Nuclepore8 Catalog No. 232300, Costar Corp., Cambridge,
                  MA 02140).

          2.1.3.2  Wipe sampler template with sampling area of 27.3 cm x 4 cm.

          2.1.3.3  Wipe  sampler movable plate-filter  retainer  consisting  of two
                  sections:  1) a 4-cm square block that is 7-mm thick and 2) a
                  5.1-cm x 4.7-cm frame.

          2.1.3.4  Gloves,  latex, powder-free,  disposable (Fisher  Scientific -  See
                  Section 2.1.1.2 or equivalent).

          2.1.3.5  Bags,  plastic, scalable (for example,  with attached wire, tape,  or
                  zip-type seal); (Ziploc 1-quart freezer bags or equivalent).
2.2   EXTRACTION

      The  applicability of this method has been  tested  with  three  of the  most
commonly  used lead-in-dust collection wipes (Section  1.2.2)  Applicability of this

method to other types of wipes will be verifiable through quality control (QC) activities
(sections 3.2 and 4.0).  The apparatus and reagents used in this procedure are as

follows:
      2.2.1  Hotplate with temperature control from 70° to 200° Celsius (Corning

6795,  Fisher Scientific Catalog No. 11-495-52A or equivalent).


      2.2.2  Beakers, 250-mL (borosilicate glass, Fisher Scientific Catalog No. 02-
540K or equivalent).


      2.2.3  Disposable wipes for preparation of laboratory control standards (LCS).

These  wipes are to  be  selected  at  random  from  the  set to be used for  sample

collection.

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      2.2.4  Electronic top-loading balance for preparation of LCSs (Mettler AJ 100
balance,  Mettler  Instruments  Corp.,  P.O. Box  71, Highstown, NJ  08520, or
equivalent).

      2.2.5  Pipetter, 200- to 1000-/;L (Oxford Benchmate, Fisher Scientific Catalog
No. 21-229 or equivalent).

      2.2.6  Glass (4-mm) rod to push wipe into beaker.

      2.2.7  Forceps, Nalgene polypropylene scissor-type (Fisher Scientific Catalog
No. 10-309 or equivalent).

      2.2.8  Hydrogen peroxide:  30% H202, volume/volume, ACS reagent grade.

      2.2.9  Nitric acid:  Concentrated, ACS spectrographic grade.

      2.2.10 Watch glass, ribbed, borosilicate glass (Fisher Scientific Catalog No. 02-
613B or equivalent).

      2.2.11  Centrifuge tubes: 50-mL disposable polypropylene (Fisher Scientific
Catalog No. 05-526B or equivalent).

      2.2.12 Centrifuge (International Equipment Company Model CL or equivalent).

      2.2.13 Deionized water in dropper or squirt bottle:  Unless otherwise indicated,
references to  deionized water shall be understood to mean reagent water as defined
by Type  1  of ASTM  Specification D  119332  (ASTM  Type 1  Water:   minimum
resistance of  16.67 megohm-cm or equivalent).

      2.2.14 NIST Traceable Secondary Reference Materials for LCS. If these are not
                                     10

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available, use a NIST SRM such as NIST SRM 1648 (Urban particulate matter); SRM
2583 (Lead in dust); SRM 2704 (Buffalo River sediment); or SRM 1 579 or 2582 (Lead
in paint).

      2.2.15 Automatic  pipettor:  10-mL capacity, 0.1-mL  subdivision  (Universal
Repipet Dispenser, VWR  Scientific, 1230 Kennestone  Circle, Marietta, GA 30066,
Catalog No. 53528-168,  or equivalent).

      2.2.16 Two- and three-mL Class A volumetric pipettes.
      2.2.17 Chemical fume hood, Kewaunee Scientific Equipment Corp., Adrian, Ml
49221, Airflow Supreme Model.
2.3   PROTECTIVE EQUIPMENT
      Safety equipment to be  used  for protection  from both lead  and biological
contamination during dust collection and wipe extraction is as follows:

      2.3.1  If  significant airborne  dust  is  present  or being  generated by  the
collection  activity,  wear  a  fitted  respirator (Occupational Safety  and  Health
Administration (OSHA) Standard 29 CFR 1910.134) for dust collection (half-mask
respirator, Fisher Scientific Catalog No. 17-632 [size], and high-efficiency particulate
air (HEPA) filter/cartridge, Fisher Scientific Catalog No. 17-635-7, or equivalent).

      2.3.2  Disposable booties, coveralls, and head  covers  for dust collection in
high-lead environment (coveralls with shirt collar, tacked-on hood, elasticized wrists,
bound seams, Fisher Scientific Catalog No. 01-361-51  [size], or equivalent).

      2.3.3  Safety glasses with side shields for wipe extraction.

      2.3.4  Laboratory gloves (See  Section 2.1.1.2) and coat for wipe extraction.
                                     11

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      2.3.5  Dust mask to be worn while handling dust wipes (mask for dusts and
mists, NIOSH/OSHA TC-21C-132; Fisher Scientific Catalog 17-653 or equivalent).

      2.3.6  Heavy-duty  plastic bags  (6-mil  or  greater)  for disposal  of  personal
protection products and dust collection waste (IPCO, Inc., Catalog No. R3350BP,
IPCO, Inc., Norcross, GA 30091, or equivalent).

      2.3.7  Detergent (heavy-duty cleaner  with  sodium  metasilicate;  Bondex
International, Inc., St. Louis, MO 63122, or equivalent) and wet wipes for cleanup
           ®
(Wash 'n Dri , Softsoap Enterprises, Inc., Chasha, MN  55318, or equivalent).

      2.3.8  Filter for waste water filtration:  20-/;m pore size (Spectra/Mesh Nylon;
Fisher Scientific Catalog No. 08-670-204 or equivalent).
                                     12

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3.0   PROCEDURES
3.1   COLLECTION OF MATERIAL
      As stated earlier (Section 1.1), a variety of wipe methods is described for
collection of dust on surfaces.  Check the references for complete descriptions of
operating procedures. Three methods chosen for testing are described below:

      3.1.1  HUD Method Using Baby Wipes8 - The HUD method uses a disposable
wipe material meeting the following  criteria:  a) low lead background (less than 5
/yg/wipe14); b) a single thickness; c) durable; d) does not contain aloe or alcohol; e) can
be digested in the laboratory; f) yields 80-120% spike recovery rates; and g) remains
moist during the sampling process. A template of paper, metal, or plastic, typically
with a sampling area of 1 ft2, is placed on the surface to be sampled.
      The wipe is placed at one corner of the template and wiped side to side  with
as many horizontal "S" strokes as necessary to cover the entire template area.  The
wipe is folded in half with the contaminated side facing in and placed in the template
top corner, and the  wiping is repeated but in a top-to-bottom direction.  Finally, the
side- to-side wiping is repeated. When all the visible dust is removed, the wipe is
inserted into a labelled centrifuge tube.

      3.1.2  NIOSH Method Using Gauze or Hand Wipe13 - The NIOSH method  uses
                                ®
a 2" x 2" gauze pad or a Wash'n Dri towelette and a plastic template with a sampling
area of 10 cm x 10 cm. The template is placed over the area to be sampled, and the
surface is wiped using three to four vertical "S" strokes.  The wipe is folded with the
exposed side in, and the area is again wiped with three to four horizontal "S" strokes.
Finally, the wipe is folded once more and the area wiped with three to four vertical
"S" strokes.  The wipe is then  folded with  the exposed sides in  and placed into a
labelled plastic bag.

      3.1.3  LWW Method Using Nuclepore® Filter12'26 - The LWW method is a new
dust wipe sampling technique utilizing the LWW sampler. The sampler consists of
two sections constructed from Delrin :  (1) a movable plate-filter retainer consisting
                                     13

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of a 4-cm square block 7 mm thick and a 5.1 -cm x 4.7-cm frame that holds the 4-cm
block; and (2) a template 3 mm thick with a sampling area of 27.3 cm x 4 cm.  The
frame plus block traces the rectangular opening within the template.
      For sampling, a Nuclepore" filter cut into a rectangle of 3.8 cm x 6.35 cm is
preweighed, folded, and placed into the sample frame so that  the filter edges are
touching the frame sides. The 4-cm square block is inserted into the frame to hold
the filter in place.  The filter is wetted with deionized water and slid across the length
of the template. It is passed back and forth three times, removed from the plate-filter
retainer, and placed into an aluminum foil  pouch.

3.2   QUALITY CONTROL SAMPLES
      3.2.1   Blank -  If  a blank wipe  was not submitted from  the  field, initiate a
laboratory blank by placing a clean,  unused wipe in a clean, labelled 250-mL  glass
beaker.  The filter should come from the same  lot as those used to collect the
samples. Record  the sample number in the laboratory notebook.

      3.2.2   Quality Control Check - Initiate a QC check by placing a wipe spiked
with 250 fjg of lead in a clean, 250-mL beaker.
      Prepare the spiked wipe as follows:
      3.2.2.1 —    Place an unused, clean wipe in a clean 250-mL glass beaker.
      3.2.2.2 -    Using a  500-//L micropipette, measure 250 //L  of commercial
                  1000-/;g/mL Pb standard onto the wipe.
      3.2.2.3 --    Allow the wipe to air dry.

      3.2.3   Laboratory Control Standard - Initiate an  LCS by using the calibrated
Mettler  balance to carefully weigh out an NIST-traceable reference material (Section
2.2.1.4) on  a piece of clean  glassine weighing paper.   Record the exact weight.
Quantitatively transfer the entire amount into a clean, unused dust wipe.  Fold the
dust wipe so that all the weighed material is contained, and place  it in a clean, labelled
250-mL beaker. Record the sample number in the laboratory notebook. For example,
                                     14

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to prepare a 1000 /yg Pb LCS, 0.1 527 g of a 6550 fjg/g reference material would be
used.

3.3   EXTRACTION PROCEDURE
      The extraction process should be conducted in a chemical fume hood.
                                                                           ®
      3.3.1  Carefully remove the field sample wipe from its container using Teflon
tipped tweezers or clean, gloved fingers.

      3.3.2  Place the wipe in a clean, labelled 250-mL glass beaker and push down
with an acid-washed glass rod.

      3.3.3  Using a volumetric pipette, add 3 ml of 30% hydrogen peroxide.

      3.3.4  Add  20 ml_ of concentrated nitric acid using the automatic pipettor.
Use the glass rod to mix and agitate the wipe and extraction reagents until the wipe
is thoroughly wetted. Withdraw the glass rod, rinsing it with about 1 ml of deionized
water.  Allow the  sample to sit until any visible reaction ceases.

      3.3.5  Place the beaker on a hotplate and cover with a ribbed  watch glass.

      3.3.6  Turn on the hotplate  to the level  necessary to achieve  a  slow reflux.
The temperature setting required to achieve a slow reflux will depend  upon the type
of wipe being extracted, the temperature of the laboratory, and  the model of the
hotplate. Do not allow the extraction solution to boil.

      3.3.7  After 20  minutes, cautiously add  2 ml of 30% hydrogen peroxide.

      3.3.8  Continue to reflux until the volume has decreased and the sample is
nearly dry.  Do not allow to evaporate completely. There must be some liquid left to
ensure that the Pb is not lost through splattering or formation and loss of aerosols.
                                     15

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      3.3.9  Add 5 ml of concentrated nitric acid and repeat the reflux step to near
dryness.

      3.3.10 Carefully remove the beaker from the hotplate and allow to cool.

      3.3.11 Using a volumetric pipette, add 5 ml_ of concentrated nitric acid to the
sample beaker.

      3.3.12 Using a squirt bottle or dropper, rinse the watch glass with 3 - 5 ml_ of
deionized water, being careful to catch all the rinsate in the sample beaker.

      3.3.13 Carefully  pour  the  sample   liquid  into  a clean,  labelled,  50-mL
polyethylene centrifuge tube.  If any undissolved material remains in the beaker, press
the wipe material down using a clean glass  rod to  extract as much solution as
possible.

      3.3.14 Using a squirt bottle or dropper and small quantities of deionized water,
carefully rinse all interior surfaces of the beaker  and pour the rinsate into the same
centrifuge tube that contains the sample. Repeat the rinse step at least three times,
but do not exceed a final volume of 50 ml_.

      3.3.15 Dilute  to the mark on the centrifuge tube with  deionized water to
achieve  a final volume of 50 ml_. This dilution results in a nitric acid concentration of
approximately 10%.

      3.3.16 Allow  any undissolved particulate matter to settle out overnight,  if
necessary, or  centrifuge at 2500 rpm  for 25 minutes.  If the extract is not  to be
analyzed immediately, decant the solution into a separate clean, labelled  centrifuge
tube.
                                      16

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      3.3.17 The sample  is  now  ready for lead analysis  using  the  selected
instrumental technique, atomic absorption spectroscopy (AAS)  or ICP.21'25

3.4   DATA PROCESSING
      AAS or ICP analysis will result in values of /yg Pb/mL for the  extracts.  To
convert from fjg Pb/mL to //g Pb/wipe, use this formula:

              /yg Pb/wipe  = /vg/mL measured x DF1 x 50 mL/wipe

      where  DF1 = any  dilution performed prior to analysis  due  to high lead
concentrations.
                                    17

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4.0   QUALITY CONTROL
4.1   SAMPLE COLLECTION
      Check original references for details of QC procedures for sample collection.
General procedures to be applied include the following:
      4.1.1  Only use wipes that are uniform from one to another in size, thickness,
and appearance.

      4.1.2  Only use wipes that, from wipe to wipe, appear to have similar loadings
of solubilization or wetting agents.

      4.1.3  Avoid contamination of wipes before and after use.

      4.1.4  Make all reasonable attempts to maintain constant and uniform pressure
while using an individual wipe and from  wipe to wipe.

      4.1.5  Maintain uniform wiping motions from wipe to wipe.

      4.1.6  Place wipes in labelled containers.

4.2   WIPE EXTRACTION
      4.2.1  Remove used  wipes from containers carefully and deliberately to avoid
dust sample  loss.

      4.2.2  Immerse each wipe as completely as possible in extraction reagents.

      4.2.3  Do not  allow extraction solution to boil as this may result in splattering
and sample loss.

4.3   QUALITY CONTROL SAMPLES
      Preparation of the QC samples is described in Section 3.2.  Criteria for the
extraction procedure being under control are as follows:
                                     18

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      4.3.1 Blank - The blank wipe shall contain  < 5 jjg Pb.  If a higher level is
measured,  repeat the blank analysis. If this blank is also > 5 //g Pb per wipe, either
identify a new source of wipes that have blank values < 5 fjg Pb per wipe and discard
the current batch, or make replicate measurements of the blank (n  = 5 to 7) and
calculate an average blank value.  Report this value with the field sample results.

      4.3.2 Quality Control Check - The QC check  shall yield a recovery of > 90%.
If the recovery is < 90%, repeat the test. If the repeat value is also < 90%, identify
the source(s) of error, including, for example, overheating of the digestion beaker or
miscalibration of the measurement instrument, and make appropriate corrections.

      4.3.3 Laboratory Control Standard - The LCS shall yield a recovery between 80
and 120%  relative to that which would be achieved with direct HN03/H202 digestion
of the reference material.  If the recovery is outside these limits, repeat the test.  If
the recovery remains outside the 80 to 120% window, either (1) identify the source(s)
of error and make appropriate corrections, or (2) make replicate measurements of the
LCS (n = 5 to 7) and calculate an average recovery  value.  Report this value with the
field sample results.
                                      19

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5.0   SAFETY
5.1   COLLECTION
      Appropriate  safety procedures must be followed during collection  of  dust
material from paint abatement sites or other sites that might have high airborne lead
levels. Collection from areas where paint chips and dust could contaminate a person
requires full-body protection to  protect the worker and to prevent take-home lead
contamination.  This includes wearing disposable booties, coveralls, head cover, and
gloves during collection. A respirator and safety glasses with side shields or goggles
must also be worn. At the end of the collection period, remove the disposable safety
wear in a relatively clean area and place it in a plastic bag for disposal (Section  6.0).
After  collecting the dust samples, take a shower as soon as is practically possible.
      If worker contamination is not a potential problem, gloves still need to be used
to prevent contamination of the samples. In some cases, the use of booties may also
be needed.

5.2   ANALYSIS
      Take normal laboratory precautions when digesting the  dust wipe samples.
Wear  gloves,  a laboratory coat, and safety glasses with side shields when performing
acid-based extractions. Also, follow the manufacturer's instructions for safe usage
of the ICP or  AAS.
                                     20

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6.0   WASTE DISPOSAL
6.1   PROTECTIVE CLOTHING
      Disposable protective clothing including dust masks and spent respirator dust
filter cartridges will generally not be categorized as hazardous waste because they
typically pass the EPA Toxicity Characteristic Leaching Procedure (TCLP).33  If there
is any uncertainty about the characterization of these materials, subject them to the
TCLP.  This procedure involves an extraction in an aqueous solution at constant pH
in a closed vessel for 18 ± 2 hours followed by analysis of the solution for lead. If
the extracted lead  exceeds 5 mg/L, consider the material a hazardous waste, and
place it in a State-licensed  or -permitted hazardous waste landfill.  If this level  is not
exceeded, place the material in a municipal landfill.

6.2   WASH WATER
      Filter wash water using a 20-/;m pore  size filter (Section 2.3.8) and allow to
drain into  a sanitary sewer system. A coarse screen may be used as a prefilter.

6.3   EXCESS DUST WIPE SAMPLES
      Subject excess dust wipe samples to the TCLP and treat them as hazardous
waste should the extract exceed the allowed limit of 5 mg/L.

6.4   SOLUTION WASTE
      Pour all leftover extract solutions, reagent wastes, and rinse water into a plastic
carboy.  Rinse with water any centrifuge tubes or other vessels containing nitric acid
as one of the reagents before putting them into a plastic bag for disposal or  reuse
after cleaning.  Dispose of waste solutions according to applicable regulations.
                                     21

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7.0   CORRECTIVE ACTION
      See Section 4.3 for corrective actions in response to unacceptable QC sample
analysis results.
      Corrective action for the measurement of lead is described in the "Standard
Operating Procedure for Lead in Paint by Hotplate- or Microwave-Based Acid Digestion
and Atomic Absorption of Inductively Coupled Plasma Emission Spectrometry."25
                                    22

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8.0  REFERENCES

1.     Agency for Toxic Substances and Disease Registry. "The Nature and Extent
      of Lead Poisoning in Children in the United States:  A Report to Congress."
      U.S. Department of Health and Human Services, 1988.

2.     Grand, L.D., and J.M. Davis.  "Effects of Low Level Lead Exposure on Pediatric
      Neurobehavioral Development: Current Finds and Future Direction." In: Smith,
      M.S., L.D. Grant, and A.I. Sors, eds.  Lead Exposure and Child Development:
      An International Assessment. Kluwer Academic Publishers: London, pp. 49-
      115, 1989.

3.     Goyer, R.A.  "Toxic Effects of Metals." In: Klassen, C.D., M.O. Amdur, and
      J. Doull, eds. Casarett and Doull's Toxicology, Third Edition, Macmillan:  New
      York, 1986.

4.     Que Hee,  S.S., B. Peace, C.S. Clark, J.R. Boyle, R.L. Bornshein, and P.B.
      Hammond.  "Evolution  of efficient methods to sample lead  sources, such as
      house dust and hand dust, in the homes of children." Environmental Research,
      38:  77-95, 1985.

5.     Roberts, J.W.,  W.T. Budd, M.G.  Ruby, A.E. Bond,  R.G. Lewis, R.W. Weiner,
      and D.E. Camann. "Development and field testing of a high volume sampler for
      pesticides and toxics in dust." Journal of Exposure Analysis and Environmental
      Epidemiology. 1 (2) 143-155, 1991.

6.     ASTM ES 30-94.  "Emergency Standard Practice for the Field Collection of
      Dust Samples Using Wipe Sampling Methods for Lead Determination by Atomic
      Spectrometry Techniques." ASTM Standards  on Lead-Based Paint Abatement
      in Buildings:  Am. Soc. Test. Mat., Philadelphia, PA 19103.  1994.

7.     Georgia Technical Research  Institute.  "Georgia Technical Research Institute
      Wipe Sampling Procedures: Inspecting for Lead Hazards and Lead-Based Paint
      Risk Assessment." 1993.

8.     Office of  Public and Indian Housing, Department of Housing and  Urban
      Development. "HUD wipe sampling procedure."  In: Lead-Based Paint: Interim
      Guidelines for  Hazard  Identification and Abatement in Public and  Indian
      Housing.  U.S.  Government Printing  Office, Washington, DC, 1990.

9.     Farfel, M.R., and J.J. Chisolm.  "Health  and environmental outcomes of
      traditional and modified practices for abatement of lead-based paint." Am. J.
      Public Health, 80: 1240,  1990.

10.   Lepow, M.L., L.  Bruckman, R.A. Rubino, S.  Markowitz,  M. Gillette, and J.
      Kapish.  "Role  of airborne lead in increased body burden of lead in Hartford
      children."  Environmental Health Perspectives. 99:  1974.


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11.   Rabinowitz, M., A. Leviton, H.  Needleman, D.  Bellinger,  and C. Waternaux.
      "Environmental correlates of infant blood levels in  Boston."  Environmental
      Research. 38:  96, 1985.

12.   Lioy, P.J., T. Wainman, and C. Weisel.  "A wipe sampler  for the quantitative
      measurement of dust on smooth surfaces:  Laboratory performance studies."
      J. Exp. Anal, and Environ. Epidem.. 3:  315, 1993.

13.   Eller, P.M. Lead in Surface Wipe Samples, Method 9100. National Institute for
      Occupational Safety and Health (NIOSH)   In:  NIOSH  Manual of Analytical
      Methods. Fourth Edition, 1994.

14.   Millson, M., P.M. Eller,  and K. Ashley, "Evaluation of Wipe Sampling Materials
      for Lead in Surface Dust." Am. Ind. Hyg. Assoc. J.. 55:  339-342 (1994).

15.   Stark, A.D., R.F.  Quah, J.W. Meigs, and E.R. DeLouise.  "The relationship of
      environmental lead to blood-lead levels in children."  Environmental Research,
      27:  372, 1982.

16.   Timperi, R.  Dust collection protocol. Department of  Public Health, Health and
      Human Services,  Commonwealth of Massachusetts, Boston, MA.  1992.

17.   Hayes, J.  Dust sampling protocol.  Environmental  Health Services Section,
      State of North Carolina, P.O. Box 27687, Raleigh, NC.  1992.

18.   Vostal, J.J., E. Taves,  J.W. Sayre, and E.  Charney.  Lead analysis of house
      dust:  A method for the detection of another source of lead  exposure in  inner
      city children. Environ.  Health Perspec.,7:  91, 1974.

19.   Chavalitnikul, C. and L. Levin. "A laboratory evaluation of wipe testing based
      on lead oxide surface contamination."  Am. Ind. Hyg. Assoc. J.,  45:   311,
      1984.

20.   Williams, E.E.,  D.A.  Binstock, J.A.  O'Rourke, P.M.  Grohse,  and   W.F.
      Gutknecht.   "Evaluation of Hotplate-  and Microwave-Based Methods for
      Extracting Lead  in  Paint,  Dust,  and Soil with Measurement  by Atomic
      Absorption   Spectrometry   and  Inductively  Coupled  Plasma   Emission
      Spectrometry."  EPA 600/R-94/147, U.S. Environmental  Protection Agency,
      Research Triangle Park, NC,  1994.

21.   ASTM, ES 36-94. Emergency Standard Practice for Hotplate  Digestion of Dust
      Wipe Samples  for Determination of Lead by Atomic Spectroscopy.  ASTM
      Standards on Lead-Based Paint Abatement in Buildings:  Am. Soc. Test. Mat.,
      Philadelphia, PA,  19103. 1994.
                                    24

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22.   Eller, P.M.   Lead  on Air Filters,  Method  7105.   National  Institute of
      Occupational Safety  and  Health  (NIOSH).   NIOSH  Manual of Analytical
      Methods, Fourth Edition, 1994.

23.   ASTM,  ES 33-94.  Emergency Standard Practice for Preparation of Airborne
      Particulate Lead  Samples  Collected During Abatement and  Construction
      Activities for Subsequent Analysis by Atomic Spectrometry. ASTM Standards
      on  Lead-Based  Paint  Abatement  in  Buildings:   Am.  Soc.  Test.  Mat.,
      Philadelphia, PA 19103.  1994.

24.   Azimuth Laboratories.  "Azimuth  Method  No.  Az-M-105,  Revision  No. 2:
      Preparation Procedure for Lead (Pb) Analysis - Dust Wipe Samples." Analytical
      Methods Manual. October 1992.

25.   Binstock, D.A., D.L. Hardison, P.M. Grohse,  and W.F. Gutknecht. "Standard
      Operating Procedure for Lead in Paint by Hotplate- or Microwave-Based Acid
      Digestion and Atomic  Absorption or Inductively Coupled Plasma Emission
      Spectrometry."  EPA 600/8-91/213, U.S.  Environmental Protection Agency,
      Research Triangle Park, NC, 1991,  19 pp.  Available  from NTIS, Springfield,
      VA; NTIS PB92-114172.

26.   "The National Human Exposure Assessment  Survey (NHEXAS):  A Workshop
      to Identify Optimal Dermal Exposure Sampling Methodologies." January 10-11,
      1994; EPA Contract 68-D1-0009.   U.S. Environmental Protection Agency,
      Research Triangle Park, NC.

27.   Little Ones Baby Wash Cloths®, K-Mart Corporation, Troy, Ml 48084.

28.   Wash'n Dri Moist Disposable Towelettes", Softsoap Enterprises Inc., Chaska,
      MN 55318.

29.   Nuclepore Filtration Products.  Costar Corporation, Cambridge, MA 02140,
      CAT #232300.

30.   American Industrial Hygiene Association (AIHA) Environmental Lead Proficiency
      Analytical Testing (ELPAT) Program, 2700  Prosperity Avenue, Suite  250,
      Fairfax, VA 22031.

31.   Binstock, D.A., E.D. Estes, E.E. Williams, J.D. Neefus, and W.F. Gutknecht.
      "Development and Evaluation of a Procedure for Determination of Lead on Dust
      Wipes  by Hotplate Acid   Digestion."   EPA Contract  68-D1-0009,  U.S.
      Environmental Protection Agency, Research Triangle Park, NC, 1995.
                                    25

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32.   American Society for  Testing and  Materials.   "Standard  Specification for
      Reagent Water,  Designation D 1193-77 (Reapproved 1983)."  1991 Annual
      Book of ASTM Standards. Vol. 11.03, 1991. 3 pp.

33.   Toxicity Characteristic Leaching Procedure. Federal Register, Vol. 55, No. 126,
      Friday, June 29, 1990.
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