OSWER 9285.7-81
DECEMBER 2008
GUIDANCE FOR THE SAMPLING AND ANALYSIS
OF LEAD
IN INDOOR RESIDENTIAL DUST
FOR USE IN
THE INTEGRATED EXPOSURE UPTAKE
BIOKINETIC (IEUBK) MODEL
PREPARED BY THE
LEAD COMMITTEE OF THE
TECHNICAL REVIEW WORKGROUP FOR METALS AND ASBESTOS
OFFICE OF SUPERFUND REMEDIATION AND TECHNOLOGY INNOVATION
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
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Members of the Lead Committee of the
Technical Review Workgroup for Metals and Asbestos
Region 1 Region 8
Mary Ballew Helen Dawson
Region 2 Region 10
Mark Maddaloni Marc Stifelman
Julie McPherson
OSRTI
Region 3 Aaron Yeow (co-chair)
Dawn loven
Linda Watson ORD NCEA-Cincinnati
Harlal Choudhury
Region 4
Kevin Koporec ORD NCEA-RTP
Andrew Rooney
Region 5
Andrew Podowski Associate Member
Scott Everett (Utah DEQ)
Region 6
Ghassan Khoury Advisors-Washington DC
Karen Hogan (ORD NCEA)
Region 7 Paul White (ORD NCEA)
Michael Beringer (co-chair) Larry Zaragoza (OSRTI)
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GUIDANCE FOR THE SAMPLING AND ANALYSIS OF LEAD
IN INDOOR RESIDENTIAL DUST FOR USE IN
THE INTEGRATED EXPOSURE UPTAKE BIOKINETIC (IEUBK) MODEL
1.0 INTRODUCTION
1.1 PURPOSE AND OBJECTIVES
The purpose of this guidance document is to recommend methods for collecting and
analyzing indoor residential dust data to estimate the mean concentration of lead in dust for use
in the Integrated Exposure Uptake Biokinetic (IEUBK) model. The recommendations apply to
applications of the IEUBK model in Superfund lead risk assessments and may not be appropriate
for other applications (e.g., HUD lead risk assessments). Implementation of the sampling and
analysis recommendations in this document will enhance consistency in lead risk assessments at
Superfund sites. It is recommended that EPA risk assessors and risk managers consult with the
Lead Committee of the Technical Review Workgroup (TRW) for Metals and Asbestos if site
sampling plans specify (or existing data were obtained using) sampling methods that differ from
those recommended in this document.
This document provides technical and policy guidance to EPA staff on making risk
management decisions for contaminated sites. It also provides information to the public and to
the regulated community on how EPA intends to exercise its discretion in implementing its
regulations at contaminated sites. This document does not substitute for statutes that EPA
administers, EPA implementing regulations, nor is it a regulation itself. This document does not
impose legally-binding requirements on EPA, states, or the regulated community, and may not
apply to a particular situation based upon the specific circumstances. Rather, the document
suggests approaches that may be used at particular sites, as appropriate, given site-specific
circumstances.
1.2 BACKGROUND
Due to the widespread use and ubiquitous nature of lead, humans are exposed to lead
from multiple exposure pathways including ingestion of lead-contaminated soil, dust, water, and
food, as well as inhalation of lead-containing particles of soil or dust in air. The predominant
pathway for lead exposure in young children is ingestion of indoor surface dust, as a result of the
hand-to-mouth pathway (U.S. EPA, 1986; Lanphear et al., 1998, 2002; Sterling et al., 1998;
Succop et al., 1998; ATSDR, 1999; Manton, et al., 2000). Studies have shown that lead-
contaminated house dust is the strongest predictor of blood lead (PbB) levels in children (Roberts
and Dickey, 1995; Lanphear et al., 1998, 2002; Succop et al., 1998; Jacobs et al., 2002).
In Superfund lead risk assessments, lead in indoor dust typically is accounted for in the
IEUBK model as an input parameter. By default, indoor dust lead concentrations are estimated
from outdoor soil lead concentrations using the mass fraction of soil in indoor dust variable
(MSD). However, the accuracy of the IEUBK model estimates for a specific site will improve
when site-specific exposure data for media concentrations, such as indoor dust, are used. When
feasible, the use of site-specific residential dust lead data is preferred over the use of the default
IEUBK model's indoor dust calculations. The intent of collecting indoor dust is to better
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characterize risk at the site, not necessarily for indoor dust remediation. There are limitations on
EPA's authority to abate interior lead dust contamination to the extent they are not related to
releases or threatened releases to the environment.1 Remediation of outdoor soil contamination
using preliminary remediation goals (PRGs) informed by the IEUBK model would be expected
to reduce the concentration of lead in indoor dust over time.
Site-specific indoor dust sampling data, under appropriate circumstances (e.g.,
considerations of data quality and representativeness), can also be used to develop a site-specific
MSD (U.S. EPA, 1998). A site-specific MSD may then be used to calculate risk as well as in the
development of a PRO for outdoor soil at the site.
1.3 DUST DATA
1.3.1 Dust Lead Metrics and IEUBK Model Input
The amount of lead in residential dust may be quantified by two metrics: lead loading
and lead concentration. For the purposes of this guidance:
• Lead loading is the concentration of lead per unit area measured in micrograms
per square meter (|ig/m2).
• Dust loading is the amount of dust per unit area expressed as micrograms per
square meter (|ig/m2) or micrograms per square foot (jig/ft2).
• Lead concentration is the mass concentration of lead per mass of dust (Co),
typically reported as micrograms per gram (|ig/g or ppm). The IEUBK model
uses lead concentration data as the metric to represent the extent and magnitude of
lead in residential dust at a site. Dust lead concentration (Co) can be calculated
from lead loading (LPb) and dust loading (LD) as follows:
CD= Eq.(l)
However, the model also accepts inputs of lead intake (e.g., jig Pb in dust ingested/day) in the
Alternate Source module. In this case, the transformation from concentration or lead loading to
lead intake (IPb) would be as follows:
IPb=CD-ID Eq.(2)
IPb=^T-ID Eq.(3)
LD
where ID is the dust intake (jig dust ingested/day).
1 As part of the larger risk management strategy, EPA should strive to work with HUD, state and local governments,
PRPs, or individual homeowners to address these interior dust risks unrelated to site releases (U.S. EPA, 1998).
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Although the IEUBK model only accepts inputs on dust lead in units of lead
concentration, both the dust lead concentration and the dust lead loading metric have been
correlated with PbB levels in children (e.g., Clark et al., 1996; Lanphear et al., 1996) and the dust
lead loading metric is used by the U.S. Department of Housing and Urban Development (HUD)
for determining the level of lead health hazard (HUD, 2004) and effectiveness of abatement
activities (i.e., lead clearance standards) (HUD, 1995).
Using a single metric (i.e., dust lead concentration or dust lead loading) to represent a
child's exposure has its limitations. Multiple measures can provide complementary information.
For instance, dust lead concentration is the ratio of lead mass to dust mass; it does not provide a
measure of the mass of lead that is available for exposure. In contrast, dust lead loading
accounts for the mass of lead per unit area; however, it does not measure the amount of dust
present, and therefore does not provide a measurement of the concentration of lead that is
present.
2.0 RECOMMENDED DUST SAMPLING METHODS
2.1 APPROACHES FOR COMPARING SAMPLING METHOD TYPES/BASIS FOR
RECOMMENDATIONS
Various dust sampling methods, protocols, and analyses were evaluated against several
recommended criteria that are desirable for lead risk assessment using the IEUBK model and are
shown in Table 1. The recommended criteria are divided into primary criteria, which identify
methods that are capable of producing data that can be used with the IEUBK model (see
Section 1), and secondary criteria, which were developed to aid in choosing between the
alternative methods that satisfy the primary criteria. If a method did not satisfy either of the
primary criteria, it was not considered further. Those sampling methods that satisfied the
primary criteria were evaluated qualitatively against the secondary criteria as shown in Table 1.
Table 1 Recommended Criteria For Selecting Sampling Methods For Residential Dust.
Primary Criteria
1 . Measures lead concentration
2. Samples fine particles of dust
(representative of hand-to-mouth
exposure)
Secondary Criteria
3. Useful for a variety of surfaces:
hard/nonporous and soft/porous
4. Accuracy and precision (sampler
Rationale
Current IEUBK model accepts dust lead data as
concentration of lead in dust (mass basis).
Sampling methods are recommended that can adequately
measure the lead concentration in the <250 |im size
fraction (fine fraction) of dust particles, which is the size
fraction that has been associated with ingestion (U.S.
EPA, 2000). (See Section 3.3 for additional information).
Rationale
The recommended method should be compatible with a
variety of surface types.
The goal is to have low variability in sampling results,
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variability, sampling method
precision, sampling method bias)
5. Validation of method
6. Sampling cost / Ease of
implementing method
i.e., consistent from person to person. Methods with high
accuracy and precision will produce better predictions of
risk using the IEUBK.
The recommended method is supported by several studies
that document testing its accuracy and precision.
Lower per-sample cost will allow more data to be
collected that will tend to yield better estimates of dust
lead concentration.
2.2 DUST WIPE SAMPLING
Protocols for using wipe methods typically utilize a premoistened towelette or paper wipe
to collect a sample within a measured sampling area using a specific wipe pattern or number of
passes. Most wipe methods for sampling lead in house dust do not collect lead concentration or
dust loading data. (For more discussion of calculation of lead concentration, see Section 1.3.1.)
Because most dust wipe methods generally do not measure lead concentration or produce
data that can be used to calculate lead concentration, most wipe methods do not satisfy primary
criterion #1. Hence, most dust wipe methods are not appropriate sampling methods for use with
the IEUBK model. However, there are exceptions, such as the Vostal, Farfel, Lioy-Wiesel-
Wainman (LWW) (Adgate et al., 1995) and the Edwards/Lioy (EL) (Edwards and Lioy, 1999)2
wipe methods, which do allow for collection of data that can be used to calculate lead
concentration, and thus satisfy primary criteria #1. These wipe methods, however, do not sample
fine particles of dust (<250 jim) and thus do not satisfy criterion #2. Hence, these methods are
not recommended for collecting data for use in the IEUBK model.
Although dust wipe methods are routinely used for HUD and produce data that are
informative for HUD, dust wipe methods are not recommended dust sampling methods for
Superfund lead risk assessments using the IEUBK model. They do not satisfy primary
criterion #1 and/or #2.
2.3 VACUUM METHODS
A large variety of vacuum devices are available that range from commercial vacuums to
hand-held personal air sampling pumps. The following discussion presents an overview and
evaluation of low flow and high flow methods.
The LWW and EL wipe methods have been used to measure lead concentration. The LWW method was designed for
bare, smooth surfaces. The EL method has been used for bare and carpeted surfaces, although there are insufficient data
available to evaluate the precision of the EL method.
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2.3.1 Low Flow
Several low flow vacuum approaches have been described in the literature. For example,
the University of Cincinnati Method low flow vacuum was described by Que Hee et al. (1985).
This method has two variants, referred to as the DVM ("dust vacuum method") and the MVM
("modified vacuum method"). The sampling device is constructed from common industrial
hygiene sampling materials (U.S. EPA, 1995a) by attaching a filter cassette with Tygon tubing to
a standard industrial hygiene vacuum pump (Reynolds et al., 1997). The pump flow rate is 2.5 to
3.0 liters per minute (0.11 cubic feet per minute) and is designed to collect the particle size
fraction of dust (<250 jim) that has been found to stick to a child's hands (U.S. EPA, 1995a).
(See Section 3.3 for additional information.)
2.3.2 High Flow
There are a wide variety of high flow vacuum methods available. In general, the high
flow samplers provide flexibility for sampling in large or small areas, and because of their high
flow rate may require less time to sample as compared to low flow methods. Selected high flow
methods are discussed below in terms of their distinguishing characteristics that relate to the
secondary criteria.
The Comprehensive Abatement Performance Study (CAPS) cyclone is a portable sampler
with a hand-held cyclone vacuum attached to an AC-powered particle separation chamber with
PVC piping and fittings. Advantages of this device are that it is easy to use, very portable,
inexpensive, and can be made from parts that are readily available in hardware stores. This
device was used in the EPA Comprehensive Abatement Performance Study and developed by
the Midwest Research Institute (Battelle, 1995).
Commercial vacuums have also been used in a variety of ways for sampling house dust
for lead concentration and lead loading. One method requires the use of preweighed vacuum
cleaner bags as described in the modified American Society Testing and Materials (ASTM)
method F608-79 (ASTM, 1987). The dust collected in the vacuum bag is analyzed for lead
concentration per gram of dust (|ig/g). Using this method, the metric lead loading can be
estimated for an area of the home such as the floor. The estimated lead concentration is
multiplied by the mass of dust per unit area, or dust loading. Samples taken from vacuums of
residential homes, particularly the fine dust that has settled at the bottom of the vacuum bag,
have been used for lead concentration analysis (Kaye et al., 1987; Moffat, 1989; Davies et al.,
1990; Thornton et al., 1990; Jensen, 1992; U.S. EPA, 1995a). Commercial vacuums such as the
GS80 (NILFISK of America, Inc.) have also been used for house dust lead sampling. The GS80
is a high-efficiency industrial vacuum with a three-filter system — a pre-filter vacuum bag,
microfilter, and high efficiency particulate air (HEPA) filter. Another type of commercial
vacuum used for sampling lead in house dust is the "Omega Vac", a hand-held vacuum with a
HEPA filter produced by ATRIX International, Inc.
There are also high volume surface samplers (HVS series) that were first designed to
assess pesticide concentrations in carpet dust (Roberts et al., 1993). The HVS2 is a high
powered vacuum cleaner designed to sample dust from carpeted and uncarpeted surfaces. It has
a nozzle that can be adjusted to a specific static pressure and air flow rate. The HVS2 was
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incorporated into the ASTM method "Standard Practice for Collection of Floor Dust for
Chemical Analysis (D5438-93)" (1993). The HVS3 is a lighter version of the HVS2 due to the
removal of the quartz fiber filter; it has a flow rate of 20 cubic feet per minute. The ASTM
method for collection of floor dust for chemical analysis has also been updated (ASTM, 2005).
The ASTM method is generally recommended as an appropriate method for collection of indoor
dust at Superfund sites. The BRM-HVS3 is a smaller and more portable version of the HVS3. It
has the same cyclone vacuum as the standard HVS3, but uses a hand-held vacuum as the particle
separator. Its flow rate is 15-15.5 cubic feet per minute. Another version of the HVS3 that can
be used to sample surfaces in small areas is an HVS3 with an attachable small wand. It was
developed by Lewis at EPA in 1993 (Lewis, 1993).
2.3.3 Evaluation of Vacuum Methods
In general, vacuum methods allow for the collection of dust lead concentration, lead
loading, and dust loading. Vacuum methods also typically collect and allow users to sample fine
particles of dust by sieving. Thus, vacuum methods satisfy the primary criteria. Both low-flow
and high-flow vacuum methods satisfy secondary criteria #3 - they are generally useful for a
variety of surfaces (hard/nonporous and soft/porous). The remaining secondary criteria (e.g.,
sampler accuracy and efficiency) were evaluated using published reports of studies that
compared vacuum devices.
In a study (Bero et al., 1997) comparing the efficiencies of low and high flow cyclonic
vacuums, the HVS3 (upright version) had a 101% dust lead concentration efficiency compared to
the actual concentration of lead applied to the sampling surface. The two low-flow vacuums
(MVM and Sirchee-Spittler) had lead concentrations 10% higher than the actual concentration.
The particle size distribution of collected soil particles and dust removal efficiency was
comparable for the high-flow cyclonic vacuums (including the HVS3), but much lower for the
low-flow vacuums. In another study (Sterling et al., 1999) comparing collection efficiency and
precision, the HVS3 had a higher collection efficiency and precision than the DVM (also called
MVM) and the wipe sampling method for hard and soft surfaces. In a similar study (Lanphear et
al., 1995), the BRM version of the HVS3 reported greater collection efficiency than the DVM or
MVM method.
These studies indicate that high-volume cyclonic vacuums methods have greater
precision and collection efficiency than low flow vacuum methods. High flow-vacuum methods
satisfy secondary criteria #4 and #5.
3.0 SAMPLING AND ANALYSIS RECOMMENDATIONS
Because IEUBK model accuracy is improved when site-specific information is used, it is
recommended that residential dust samples be collected from all residences or as many
residences as possible for Superfund site risk assessment. When it is not feasible to sample all
homes, it is recommended that residences be randomly selected from the population of the
residences where soil samples will be collected. Under appropriate circumstances, these data
from representative homes may be appropriate to form the basis of a site-specific MSo to
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estimate an indoor dust concentration for those homes where no indoor dust lead concentration
data are available (U.S. EPA, 1998). A site-specific MSD may also be used when developing a
PRG number for the site.
High-volume cyclonic vacuums are recommended for collecting house dust lead data
according to the ASTM method (ASTM, 2005; with the modification of using a sieve size of
250 f^m) for the IEUBK model because they provide concentration data that can be directly
entered into the model; they allow for the sampling of fine particles of dust; they are useful for a
variety of surfaces; and they have documented greater precision and collection efficiency than
other sampling methods.
3.1 SELECTION OF RESIDENCES TO SAMPLE
When it is not feasible to sample all homes, it is recommended that residences be
randomly selected from the population of the residences where soil samples will be collected.
Ideally, residences are selected using a stratified random sampling plan to increase the likelihood
of obtaining a representative sample. For the purposes of this guidance, a representative sample
is defined as a sample that contains ranges of values for attributes (e.g., PbB, soil lead
concentration, etc.) that are deemed important and that are consistent with the range of values for
the attributes that are found in the population. For example, the sampling strategy would
generally avoid homes with lead-based paint due to confounding of the determination of a site-
specific MSD- Also, it is generally recommended that paired outdoor soil and indoor dust
samples should be collected to develop a site-specific MSD. If PbB data are available, then the
population may be stratified by PbB to ensure the range of PbB levels in residences that are
included in the sample is approximately equal to the range of PbB levels in the population. For
lead case management and preventive efforts, it is preferable to maximize dust sampling in
homes occupied by pregnant women or young children.
If soil concentration data are available from previous sampling efforts (e.g., from
preliminary assessments/site investigations), then residences may also be stratified by soil
concentration. In the absence of, or in conjunction with, soil concentration data, strata may be
defined based on distance from the sources(s). This assumes the transport mechanisms are
known with some certainty (e.g., aerial deposition from a smelter), and the pattern of
contamination has not been greatly disturbed (e.g., partial cleanups). Other site-specific
variables that could be used to define strata include building age (older buildings may have lead-
based paint) and direction from the source (to account for prevailing wind directions when aerial
transport may be an important mechanism for contaminant transport at the site).
The expertise of a statistician is recommended for assistance in designing the sampling
plan. Ideally, environmental samples (and PbB samples, if collected) will be collected within the
same period of time (see Section 3.5 for discussion).
3.2 SELECTION OF SAMPLING LOCATIONS WITHIN RESIDENCES
For site-specific Superfund risk assessment using the IEUBK model, the purpose of
collecting dust samples generally is to estimate the exposure concentration (the arithmetic mean)
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of lead in dust. A schematic drawing of a residence (Figure 1) and flowchart (Figure 2) have
been prepared to illustrate the selection of sampling locations within a residence. The location of
samples within the residence may be selected to assess the variability of dust lead concentration
within the residence while also characterizing the dust lead concentration in areas of the home
where children <7 years (<84 months) of age spend most of their time. Dust sample collection
may be conducted on hard or carpeted surfaces, depending on the location where children spend
their time. The committee recommends sampling from floors because these areas best represent
average long-term dust exposure for children.
Parents may be able to provide information on what areas of the home the children spend
the most time. If the activity patterns of a child are known with some certainty, a time-weighted
average dust lead concentration could be estimated by collecting samples in the areas of the
home that are frequented by the child. In addition, a weighted average of these sample
measurements could be calculated by using the fraction of the day the child spends in each area
of the home as the weights.
When information on children's activity patterns is not known (e.g., future exposure
scenarios and current exposure scenarios for homes without children), judgment can be used to
locate samples where children would be likely to spend most of their time. If children are not
present in the home, it is recommended that samples be collected from areas that are most
frequently used by the residents. At a minimum, it is recommended that sample locations
include 1) either a bedroom of a child who is <7 years old (<84 months) or any bedroom, if
children are not present in the home, 2) the most frequently used living space (preferably by
children <7 years old (<84 months), if present), and 3) just inside the most frequently used
entrance to the home (see Table 2 and Figures 1 and 2). Special consideration for sampling attic
dust is discussed in the Appendix.
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Table 2. Recommendations For Sampling Locations Within Residences For Dust Lead Concentration.
Room
A bedroom used by a
<84-month child or any
bedroom (when no
children occupy the
home)
The living space most
frequently used (e.g.,
living room, kitchen)
An entrance most
frequently used
Other various rooms
Selection of
Room
Typically sample at least
one child's bedroom3
Typically sample
Typically sample
Optional, based on activity
patterns of child <84 months
Selection of
Sampling Location Within the Room
Based on activity patterns or random method
Based on activity patterns or random method
Sample just inside most frequently used
entrance, in main traffic pattern
Use random method
alf there are no children <84 months old in the residence, a bedroom may be selected at random for
sampling. Bedrooms that are used as offices, dens, etc. may be the most frequently used living space and as
such, are recommended sampling locations.
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Within each selected residence
child <84 months
old present?
Yes
Select child closest to 2 years
of age (<24 months)
Select this child's bedroom,
and the other most frequently
visited room by this child
Randomly select a
bedroom and the most
frequently used room in
the residence
Within the selected
bedroom and the most
commonly used room
(e.g., kitchen, living
room) collect floor
sample (random
selection or on activity-
pattern based, if known)
Sample floor
just inside
most
frequently
used
entrance
Optional: sample
floor in additional
rooms, using
random selection
or based on activity
patterns
Figure 1. Recommendations for selecting rooms, and room components, for dust lead sampling.
The purpose of sampling is to estimate the average residential dust lead concentration for use with the
IEUBK model. The sampling design should employ a mixture of activity patterns (when known) and
random sampling methods.
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most frequently
used entrance
main
entrance
dust sampling
locations
living room
kitchen
>
bedroom #
2
o
family room
/\
outdoor
deck
entrances
A.
master
bedroom
bath room
bedroom #3
child's
bedroom #4
bath
room
Figure 2. Typical sampling locations for residential dust sampling. The sample locations and the number of
samples are hypothetical. The actual sample locations should be selected based on the general activity patterns of
the children. In some residences the most frequently used entrance may be the garage. Laundry rooms may be
sources of substantial exposure to young children, particularly when one or more members of the residence are
employed in an occupation, or participate in a hobby, where lead contamination is present. It is recommended that
samples be collected: 1) from either a bedroom of a child who is <7 years old (<84 months) or any bedroom if
children are not present in the home, 2) in the most frequently used living space (preferably by children <7 years
old (<84 months), if present, and 3) just inside the most frequently used entrance to the home.
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3.3 SAMPLE PREPARATION AND ANALYSIS
3.3.1 Sieving
It is strongly recommended to analyze the portion of the dust sample that passes through
a No. 60 sieve (250 jim). Researchers who have examined the particle size distribution of dust
and soil on children's hands have found that dust particles <200-250 jim are most likely to stick
to a child's hands (U.S. EPA, 1995a, 2000). Sieving will also remove non-dust material from the
sample (e.g., lint, hair). Studies have also shown that there is generally an enrichment of lead in
the fine fraction of soil and dust particles (U.S. EPA, 1995a, 2000). Enrichment of lead in the
coarse fraction has also been observed, although it is thought to be far less common (U.S. EPA,
1995a).
3.3.2 Sample Digestion and Analysis
There are currently four laboratory (wet chemistry) methods that are used to measure dust
lead concentration: flame atomic absorption spectroscopy (FAA; SW846-7420), graphite
furnace atomic absorption (GFAA; SW846-7421) spectroscopy, inductively couple plasma-
atomic emission spectroscopy (ICP-AES; SW846-6010B), and inductively couple plasma-mass
spectroscopy (ICP-MS; SW846-6020). It is recommended that dust samples be prepared for
analysis by digestion according to EPA SW846-3050B or 3051. Instrument detection limits for
the digestion extract vary between 0.1 (FAA) - 1 mg/L (GFAA) (U.S. EPA, 1992, 1996);
method detection limits will be higher than the instrument detection limits, and will vary
depending upon many factors related to the analytical equipment and the sample matrix. In
addition, laboratory (stationary) X-ray fluorescence (XRF) may also be used to measure dust
lead concentration. Dust samples for XRF should be prepared using the same approach as for
outdoor soil samples (e.g., sieved, homogeneous, dried).
3.4 DATA ANALYSIS
It is recommended that an estimate of the (arithmetic) mean dust lead concentration be
used as an input to the IEUBK model. Variability in other exposure parameters (e.g., dust
ingestion rate) is represented by the geometric standard deviation (GSD) term in the IEUBK
model. It is also recommended to review each sample result individually to decide if specific
areas of the residence pose a potential lead hazard.
3.5 SEASONAL VARIATION (IN BLOOD LEAD AND DUST LEAD CONCENTRATION)
Due to frequently observed seasonal patterns in PbB levels and transport of lead indoors
(Hunter, 1977; Billick et al., 1979; Rabinowitz et al., 1985; Blatt and Weinberger, 1993; U.S.
EPA, 1995b; Johnson et al., 1996; Rothenberg et al., 1996; Edwards et al., 1998; Lorenzana et
al., 2003; Laidlaw et al., 2005), recommendations on the seasonal timing of sampling are
important for the IEUBK model. It is recommended that house dust samples be taken during the
late summer months to early fall, in order to capture peak house dust lead concentrations and
loadings potentially responsible for peak PbB concentrations reported in numerous studies
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(Hunter, 1977; Billick et al., 1979; Rabinowitz et al., 1985; Johnson et al., 1996; Lorenzana et
al., 2003).3
3.6 COMPOSITE SAMPLING ISSUES
In general, the analysis of discrete samples is preferred over composite samples to avoid
losing information on the variability of dust lead concentration within the residence. In
particular, it is not recommended to composite samples from areas of the residence with little or
no dust (low dust loading) with samples from areas with high dust loading, because exposure is
related to dust loading.
4.0 CONCLUSION
High-volume cyclonic vacuums are recommended for collecting house dust lead data
(according to ASTM methodology with a 250 jim sieve) for the IEUBK model because they
provide concentration data that can be directly entered into the model. Table 1 can be used to
evaluate the appropriateness of other methods; however, it is recommended that the TRW be
consulted prior to using data collected with other methods in Superfund lead risk assessments. It
is recommended that dust samples be collected from floors. Samples may be collected from
carpeted and bare floors. It is recommended that residential dust samples be collected from all
residences when feasible to do so. The location of samples within the residence may be selected
to assess the variability of dust lead concentration within the residence while also characterizing
the dust lead concentration in areas of the home where children <7 years of age (<84 months)
spend most of their time. Generally, it is recommended to collect samples from the following
locations: 1) either a bedroom of a child who is <7 years old (<84 months) or any bedroom if
children are not present in home, 2) the most frequently used living space (preferably by children
<7 years old (<84 months), if present), and 3) just inside the most frequently used entrance to the
home (see Table 2 and Figures 1 and 2).
3 For some locations, it may be appropriate to sample at other times of the year (e.g., wet weather season to capture
season when track-in is anticipated to be greatest). The timing of sampling is a site-specific decision.
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APPENDIX
Attic Dust Sampling and Analysis
The purpose of this appendix is to recommend methods for collecting and analyzing dust
lead data from attics or areas of the attics that are not used for living space. Attics or areas of
attics that are used for living space (e.g., bedroom[s]) should be sampled according to the
recommendations provided in Section 2.0. Data on dust lead concentrations in non-living space
areas of attics can provide useful information for risk management decisions, but should not be
used with the IEUBK model if exposure to the dust in these non-living space areas occurs very
sporadically (i.e., <1 day/week for 3 months; U.S. EPA, 2003).
Risk management issues related to the cleanup of attic dust are not addressed in this
appendix. This appendix assumes the decision to sample attic dust has already been made and
does not address how to make that determination. However, some of the factors to consider
when making that determination include:
• historical site information that suggests contamination may have occurred as a result of
outdoor soil or air sources,
• a complete exposure pathway exists between the attic dust and potentially exposed
individuals (as defined by the site conceptual exposure model),
• there is no other plausible explanation for observed elevated PbB concentrations,
• attic dust is likely to recontaminate residences that have been cleaned or have been
proposed for cleaning.
Background
Recent studies indicate that residential attic spaces can contain a number of contaminants,
including pollutants such as plutonium, pesticides, and lead. In a sampling of homes near a
nuclear test site in Nevada, Cizdziel et al. (1998) encountered plutonium in attic dust that the
authors attributed to above ground nuclear detonations that occurred in the 1950s and 1960s.
During a later resampling of the same locations, Cizdziel and Hodge (2000) detected pesticides,
some of which had been banned for many years (e.g., DDT). Cizdziel and Hodge (2000) also
found that pollutants in attic dust were enriched relative to surrounding soil. Lead was
consistently the pollutant with the highest enrichment factor; concentrations of lead in attic dust
were up to 10 times greater than the lead concentrations in nearby soils (Cizdziel and Hodge,
2000). Ilacqua et al. (2003) also detected lead in attic dust in samples of 201 houses of varying
age located in Dover Township, NJ. The study observed a positive correlation between home
age and the amount of lead in attic dust. Temporal variability of lead in attic dust closely
followed the temporal variability in lead emissions from leaded gasoline combustion.
Contamination of attic dust occurs when ambient air containing pollutants enters the attic
and airborne particulate matter settle on attic surfaces such as the floor, insulation, roof, and
rafters. In a typical attic, warm air is vented near the peak of the roof. As the warm air is vented,
cooler outside air is drawn into the attic through vents and other openings located lower in the
attic (e.g., soffit/eave vents). Reduced air flow promotes increased particulate deposition rate
and less re-entrainment. Over time, contaminated particles build up in the attic and may remain
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in the attic for the life of the home if left undisturbed. In some cases where attic dust has been
undisturbed, studies have shown that attic dust can provide a historical record of ambient air
pollution (Ilacqua et al., 2003).
Potential exposure to attic dust
Although pollutants have been observed in attic dust, the potential for exposure may be
minimal if the attic is well-sealed from the living space. In making the determination to sample
attic dust, consider the potential exposure to attic dust. If a completed exposure pathway for attic
dust has been identified, or when elevated PbB concentrations observed in children living on the
site cannot be explained by other sources, there may be a potential exposure to attic dust.
In a complete exposure pathway, children may be exposed to attic dust through direct or
indirect exposure. Direct exposure occurs when a person enters the attic space and is exposed
directly to lead contaminated dust. This is most likely to occur in homes where attics are easily
accessible (e.g., via stairways). Direct exposure can occur when bedrooms or other living spaces
are located in the attic, or through intermittent activities such as placing or retrieving storage
items in the attic. Home renovations that require entry into the attic (e.g., wiring and insulating)
or intrude into the attic (e.g., ceiling replacement, installation of skylights, or installation of attic
ladders) may result in intermittent direct exposure to attic dust (e.g., during construction) and
may represent a temporary source of lead in dust in the living spaces of the home. Indirect
exposure to attic dust can occur when attic dust enters the primary living space. An example of
this is when a directly exposed individual transports lead contaminated dust on their personal
effects (e.g., clothing, shoes, articles retrieved from attic, etc.) back into the living spaces or
when attic dust penetrates the living areas via cracks or crevices in the walls or ceilings.
There may also be a potential exposure to lead in attic dust if there are elevated PbB
concentrations4 observed in children living on the site that cannot be explained by other sources
and, one or more of the following conditions are met:
Transport of site-related lead contamination via air is known or suspected to be or to have
been a significant means of contaminant transport.
It is known that the attic dust contains high concentrations of lead (e.g., through previous
sampling efforts).
The individual has lived in the residence for an extended period of time (e.g., 3 months or
longer).
Soil lead concentrations on the property are low (e.g., <400 ppm).
Dust lead concentrations are low (e.g., <280 ppm).
Dust lead concentrations in the residence are high (e.g., >280 ppm) and lead-based paint
is not present (or the paint is in good condition and there is no known pica behavior).
Sources of lead exposure outside of the residence have not been identified.
The residence is an older home.
4 Blood lead concentration data for people who are potentially exposed to site-related contamination are not
available for many sites.
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Recommendations for sampling and analysis
A sampling plan should be developed after the determination to sample attic dust has
been made. Investigators considering sampling attics should proceed with caution to minimize
physical hazards to the sampler, prevent damage to the structure, and prevent potential
contamination of living spaces. The recommendations for sampling indoor dust given in
Section 2.0 also may be useful when sampling attic dust; however, attics often present unique
sampling requirements. For example, some houses may not have access to the attic, while others
may permit only limited access to certain parts of the attic.
Factors should be considered when deciding which houses will be sampled such as
sample locations within the attic, sample size, and sampling equipment. The sampling method
and equipment that is used for attic dust should be the same as, or sufficiently consistent with,
the methods and equipment that are used in the other areas of the residence to support valid
comparisons between the attic dust data and the dust data collected from other areas of the
residence.5
Sample locations and sample size (within each attic)
This section addresses attics, or portions thereof, that are not used for living space. If any
areas of the attic that are used for living space (e.g., bedroom[s]), these areas should be sampled
according to the recommendations provided in Section 3.0.
Determining sampling locations within each attic should be done on a site-by-site basis,
as each attic will have different physical constraints. When possible, samples should be
collected from multiple points within the attic. In some cases access will be restricted to areas
near the attic entry (e.g., attics with a trap door entry). Obstacles such as hazardous attic floor
conditions (e.g., lack of decking), insulation, limited crawl space, and the potential to damage the
structure or household contents may prevent access to all areas of the attic.
If access to the attic is available, the attic should be inspected for potential health and
safety hazards. Samples should not be collected where attic floors are not adequately supported,
electrical hazards exist, or where damage to the ceiling may result. When possible, samples
should be located near the attic entry as it is expected that this would represent the dust that is
most likely to be tracked into the living space. Samples may also be collected near eave vents
and where attic dust disturbance has been unlikely, as these areas may contain higher
concentrations and volumes of dust. When possible, consider sampling attic surfaces such as
beams, floors, insulation, roofs, and rafters.
In some cases, indoor access to the attic may not exist. In these cases, it is presumed that
the contamination of the living space from attic dust will be via indirect exposure. If it is
determined that attic sampling is required, but indoor access is not feasible, an alternative access
point may be through exterior attic vents.
5 It should be noted that for instances when attic dust is infiltrating into the residence, current risk to residents would
be represented by indoor dust lead sampling. Sampling of the attic would, in this instance, provide information
concerning potential future exposure.
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Sample equipment
Numerous types of sampling equipment exist for collecting dust samples including a
paint brush and dust pan, high-volume cyclone vacuums, and dust wipes. In previous studies, a
dustpan and fine-haired brush or paint brush have been used to sample attic dust (Cizdziel and
Hodge, 2000; Ilacqua et al., 2003); however, it is recommended to use a high-volume cyclone
vacuum like the HVS3 to collect samples whenever feasible. The vacuum should also be
thoroughly decontaminated between samples following the manufacturer's recommendations.
When it is not feasible to use a high-volume cyclone vacuum, samples may be collected using a
paint brush and dust pan, or other appropriate receptacle (e.g., polypropylene scoop). New
sampling equipment should be used for each sample, or sample equipment should be thoroughly
decontaminated between samples to avoid cross-contamination of samples. In addition, sharp
objects should not be used to sample attic dust as they may damage electrical wires in the attic.
Where dust has collected in large quantities, a disposable spoon may be used to collect a sample.
Dust samples may be stored in clean antistatic plastic containers such as bags or HDPE bottles
and delivered to an EPA certified lab for analysis.
Evaluating dust concentration data for attics
It is anticipated that attic dust samples may contain larger particles of debris such as
fiberglass, cellulose, or vermiculite insulation and that sieving normally would be appropriate.
Sample preparation and analysis should follow the recommendations provided in Section 3.0.
Attic dust lead concentration data may provide useful information for risk management
decisions. The attic dust lead concentration data should not be used with the IEUBK model if
exposure to the attic dust occurs very sporadically (i.e., <1 day/week for 3 months [U.S. EPA,
2003]). If the potential exists in the future that attic dust will impact indoor exposures, as
determined on a residence-specific basis, this potential exposure to attic dust should be further
evaluated. If the attic is used for living space (e.g., as a bedroom) these data may be used in the
IEUBK model as indoor dust concentration to estimate risk from the exposure.
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REFERENCES
Adgate J.L., C. Weisel, Y. Wang, G.G. Rhoads, and PJ. Lioy. 1995. Lead in house dust:
relationships between exposure metrics. Environmental Research. 70:134-147.
ASTM (American Society Testing and Materials). 1987. Evaluation of carpet-embedded dirt
removal effectiveness of household vacuum cleaners (F608-79). Annual Book of ASTM
Standards, Vol. 15.07. American Society of Testing and Materials, Philadelphia, PA.
ASTM (American Society Testing and Materials). 1993. Method D 5438-93. Standard practice
for collection of dust from carpeted floors for Chemical Analysis. American Society of Testing
and Materials, Philadelphia, PA. [Withdrawn by ASTM].
ASTM (American Society Testing and Materials). 2005. Method D 5438-05. Practice for
Collection of Floor Dust for Chemical Analysis. American Society of Testing and Materials,
Philadelphia, PA.
ATSDR (Agency for Toxic Substances and Disease Registry). 1999. Toxicological profile for
lead. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.
Battelle Report to the EPA/OPPT. 1995. "Comprehensive abatement performance study.
Volume II: Detailed Statistical Results." as cited in United States Environmental Protection
Agency. 1995a. Sampling House Dust for Lead: Basic concepts and literature review.
Bero, B.N., M.C. von Braun, I.H. von Lindern, I.E. Hammel, and R.A. Korus. 1997. Evaluation
of six vacuum techniques for sampling lead-contaminated carpeted surfaces. Advances in
Environmental Research. 1:333-344.
Billick, I.H., A.S. Curran, and D.R. Shier. 1979. Analysis of pediatric blood lead levels in New
York City for 1970-1976. Environ. Health Per spec. 31:183-190.
Blatt, S.D. and H.L. Weinberger. 1993. Prevalence of lead exposure in a clinic using 1991
Centers for Disease Control and Prevention recommendations. Am. J. Dis. Child. 147:761-763.
Cizdziel, J.V., V.F. Hodge, and S.H. Fallen 1998. Plutonium anomalies in attic dust and soils at
locations surrounding the Nevada Test Site. Chemosphere. 37(6): 1157-1168.
Cizdziel, J.V. and V.F. Hodge. 2000. Attics as archives for house infiltrating pollutants: trace
elements and pesticides in attic dust and soil from southern Nevada and Utah. Microchemical
Journal. 64:85-92.
Clark, S., R.L. Bornschein, W. Pan, W. Menrath, S. Roda, and J. Grote. 1996. The relationship
between surface dust lead loadings on carpets and the blood lead of young children.
Environmental Geochemistry and Health. 18:143-146.
18
-------
Davies, D.J.A, I. Thornton, J.M. Watt, E.B. Culbard, P.O. Harvey, H.T. Delves, J.C. Sherlock,
G.A. Smart, J.F.A. Thomas, and MJ. Quinn. 1990. Lead intake and blood lead in two-year-old
U.K. urban children. The Science of the Total Environment. 90:13-29.
Edwards, R.D., EJ. Yurkow, and PJ. Lioy. 1998. Seasonal deposition of house dusts onto
household surfaces. The Science of the Total Environment. 224:69-80.
Edwards, R.D. and PJ. Lioy. 1999. The EL sampler: a press sampler for the quantitative
estimation of dermal exposure to pesticides in house dust. Journal of Exposure Analysis and
Environmental Epidemiology. 9:521-529.
HUD (U.S. Department of Housing and Urban Development). 1995. Office of lead-based paint
abatement and poisoning prevention. Guidelines for the evaluation and control of lead-based
paint hazards in housing, http://www.hud.gov/offices/lead/lbp/hudguidelines/index.cfm
HUD (U.S. Department of Housing and Urban Development). 2004. Requirements for
notification, evaluation, and reduction of lead-based paint hazards in federally owned residential
property and housing receiving federal assistance: conforming amendments and corrections.
Final Rule. Fed Reg. 69(118):34262-34276. June 21. http://www.epa.gov/fedrgstr/EPAFR-
CONTENTS/2004/June/Day-21/contents.htm
Hunter, J.M. 1977. The summer disease. An integrative model of the seasonality aspects of
childhood lead poisoning. Soc.Sci.Med. 11:691-703.
Ilacqua, V., N. Freeman, J. Fagliano, and P. Lioy. 2003. The historical record of air pollution as
defined by attic dust. Atmos Chem. 37:2379-2389.
Jacobs, D.E., R.P. Clickner, J.Y. Zhou, S.M. Viet, D.A. Marker, J.W. Rogers, D.C. Zeldin, P.
Broene, and W. Friedman. 2002. The prevalence of lead-based paint hazards in U.S. housing.
Environmental Health Perspectives. 110: A5 99-A606.
Jensen, H. 1992. Lead in Household Dust. The Science of the Total Environment. 114:1-6.
Johnson, D.L., K. McDade, and D. Griffith. 1996. Seasonal variation in pediatric blood lead
levels in Syracuse, NY, USA. Environ. Geo. and Health. 18:81-88.
Kaye, W.E., T.E. Novotny, and M. Tucker. 1987. New ceramics-related industry implicated in
elevated blood lead levels in children. Archives of Environmental Health. 42(2): 161-164.
Laidlaw, M.A.S., H.W. Mielke, G.M. Filippelli, D.L. Johnson, and C.R. Gonzales. 2005.
Seasonality and children's blood lead levels: Developing a predictive model using climatic
variables and blood lead data from Indianapolis, Indiana, Syracuse, New York, and New
Orleans, Louisiana (USA). Environ. Health Perspect. 113(6):793-800.
Lanphear, B.P., M. Emond, D.E. Jacobs, M. Weitzman, M. Tanner, N.L. Winter, B. Yakir, and
S. Eberly. 1995. A side-by-side comparison of dust collection methods for sampling lead-
contaminated house dust. Environmental Research. 68:114-123.
19
-------
Lanphear, B.P., M. Weitzman, N.L. Winter, S. Eberly, B. Yakir, M. Tanner, M. Emond, and T.
Matte. 1996. Lead-contaminated house dust and urban children's blood lead levels. American
Journal of Public Health. 86:1416-1421.
Lanphear, B.P., T.D. Matte, J. Rogers, R.P. Clickner, B. Dietz, R.L. Bornshein, P. Succop, K.R.
Mahaffey, S. Dixon, W. Galke, M. Rabinowitz, M. Farfel, C. Rohde, J. Schartz, P. Ashley, and
D.E. Jacobs. 1998. The contribution of lead-contaminated house dust and residential soil to
children's blood lead levels. Environmental Research. 79:51-68.
Lanphear, B.P., R. Hornung, M. Ho, C.R. Howard, S. Eberle, and K. Knauf. 2002.
Environmental lead exposure during early childhood. Journal of Pediatrics. 140:40-47.
Lewis, R.G. 1993, March 31. "Modified HVS3 sampler." [personal conversation]. Dr. Robert
G. Lewis, Chief, Methods Research Branch, AREAL/ORD, U.S. Environmental Protection
Agency; as cited in United States Environmental Protection Agency. 1995a. Sampling House
Dust for Lead: Basic concepts and literature review.
Lorenzana, R.M., R. Troast, M. Mastriano, M.H. Follansbee, and G.L. Diamond. 2003. Lead
intervention and pediatric blood lead levels at hazardous waste sites. Journal of Toxicology and
Environmental Health. 66:871-893.
Manton, W.I., C.R. Angle, K.L. Stanek, Y.R. Reese, and TJ. Kuehnemann. 2000. Acquisition
and retention of lead by young children. Environ. Res. 82:60-80.
Moffat, W.E. 1989. Blood lead determinants of a population living in a former lead mining area
in southern Scotland. Environmental Geochemistry and Health. ll(l):3-8.
Que Hee, S.S., B. Peace, C.S. Clark, J.R. Boyle, R.L. Bornschein, and P.B. Hammond. 1985.
Evolution of efficient methods to sample lead sources, such as house dust and hand dust, in the
homes of children. Environ. Res. 38(ll):77-95.
Rabinowitz, M., A. Leviton, H. Needleman, D. Bellinger, and C. Waternaux. 1985.
Environmental correlates of infant blood lead levels in Boston. Environ. Res. 38:96-107.
Reynolds, S.J., L. Etre, P.S. Thorne, P. Whitten, M. Selim, and W.J. Popendorf 1997.
Laboratory comparison of vacuum, OSHA, and HUD sampling methods for lead in household
dust. Amer. Indus. Hygiene Assoc. 58:439-446.
Roberts, J.W., W.T. Budd, J. Chuang, and R.G. Lewis. 1993. Chemical Contaminants in House
Dust: Occurrences and Sources. PB 93 228542. EPA-600/A-93-215.
Roberts, J.W. and P. Dickey. 1995. Exposure of children to pollutants in house dust and indoor
air. Rev. Environ. Contain. Toxicol. 143:59-78.
Rothenberg, S.J., F.A. Williams, Jr., S. Delrahim, F. Khan, M. Kraft, M. Lu, M. Manalo, M.
Sanchez, and D.J. Wooten. 1996. Blood lead levels in children in south central Los Angeles.
Arch. Environ. Health. 51(5):383-388.
20
-------
Sterling, D.A., D.L. Johnson, A.M. Murgueytio, and G. Evans. 1998. Source contribution of
lead in house dust from a lead mining waste Superfund site. J. Exp. Anal. Environ. Epidemiol.
8(3):359-373.
Sterling, D.A., K.C. Roegner, R.D. Lewis, D.A. Luke, L.C. Wilder, and S.M. Burchette. 1999.
Evaluation of four sampling methods for determining exposure of children to lead-contaminated
household dust. Environmental Research. Section A. 81:130-141.
Succop, P., R. Bornschein, K. Brown, and C. Tseng. 1998. An empirical comparisons of lead
exposure pathway models. Environ. HealthPerspect. 106(S6):1577-1583.
Thornton, I, D.J.A. Davies, and M.J. Quinn. 1990. Lead exposure in young children from dust
and soil in the United Kingdom. Environ. Health Perspect. 89:55-60.
U.S. EPA. 1986. Air Quality Criteria for Lead Volume I-IV. Environmental Criteria and
Assessment Office, Office of Research and Development, RTF, NC. EPA 600/8-83-028a-d.
U.S. EPA. 1992. Test Methods for Evaluating Solid Waste, Physical/Chemical Methods.
Method 7000A, Revision 1. July. Available online at:
http://www.epa.gov/epaoswer/hazwaste/test/main.htm.
U.S. EPA. 1995a. Sampling House Dust for Lead: Basic concepts and literature review.
http://www.epa.gov/oppt/lead/pubs/exec_summary.htm
U.S. EPA. 1995b. Residential sampling for lead: protocols for dust and soil sampling. Final
report. EPA 747-R-95-001. http://www.epa.gov/oppt/lead/pubs/qall.pdf
U.S. EPA. 1996. Test Methods for Evaluating Solid Waste, Physical/Chemical Methods.
Method 6010B, Revision 2. December, http://www.epa.gov/sw-846/main.htm
U.S. EPA. 1998. IEUBK Model Mass Fraction of Soil in Indoor Dust (MSD) Variable. EPA-
540-F-00-008, OSWER 9285.7-34. June.
http://www.epa.gov/superfund/programs/lead/products/ssmsdcol.pdf
U.S. EPA. 2000. TRW Recommendations for Sampling and Analysis of Soil at Lead (Pb) Sites.
EPA-540-F-00-010, OSWER 9285.7-38. April.
http://www.epa.gov/superfund/lead/products/sssiev.pdf
U.S. EPA. 2003. Assessing Intermittent or Variable Exposures at Lead Sites. Office of
Emergency and Remedial Response. OSWER # 9285.7-76. EPA-540-R-03-008.
http://www.epa.gov/superfund/lead/products/twa-fmal-nov2003.pdf
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