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JUL ' 4 1994
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SClO AASfE AND E v E B G £ \ c •' *£ S*"; \ S-
OSWER Directive # 9355.4-12
MEMORANDUM
SUBJECT: Revised Interim Soil Lead Guidance for CERCLA Sites and
RCRA Corrective Action Facilities^
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FROM!	Elliott P. Laws*- _\"
Assistant Administrator , N
TOs	Regional Administrators I-X
PURPOSE
As part of the Superfund Administrative Improvements
Initiative, this interim directive establishes a streamlined
approach for determining protective levels for lead in soil at
CERCLA sites and RCRA facilities that are subject to corrective
action under RCRA section 3004(u) or 3008(h) as follows:
•	It recommends screening levels for lead in soil for
residential land use (400 ppm);1
•	It describes how to develop site-specific preliminary
remediation goals (PRGs) at CERCLA sites and media
cleanup standards (MCSs) at RCRA Corrective Action
facilities for residential land use; and,
•	It describes a plan for soil lead cleanup at CERCLA
sites and RCRA Corrective Action facilities that have
multiple sources of lead.
This interim directive	oa soil
lead cleanup for CERCLA and RCRA programs (see the Background
section, 1989-1991).
*3Y Mgesaggj
Screening levels are not cleanup goals. Rather, these
screening levels may be used as a tool to determine which sites
'The residential screening level is the same concept as the level proposed ia the RCRA Corrective
Action Subpart S rule (July 27, 1990, 55 Federal Register i
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or portions of sites do not require further study and to
encourage voluntary cleanup. Screening levels are defined as a
level of contamination above which there may be enough concern to
warrant site-specific study of risks. Levels of contamination
above the screening level would NOT automatically require a
removal action, nor designate a site as "contaminated."
The residential screening level for lead described in this
directive has been calculated with the Agency's new Integrated
Exposure Uptake Biokinetic Model (IEUBK) model (Pub. # 9285,7-15-
2, PB93-963511), using default parameters. As outlined in the
Guidance Manual for the IEUBK Model for Lead in Children (Pub. #
9285.7-15-1, PB93-963510, February 1994), this model was
developed to: recognize the multimedia nature of lead exposures?
incorporate important absorption and pharmacokinetic information;
and allow the risk ir.mager to consider the potential
distributions of exposure and risk likely to occur at a site (the
model goes beyond providing a single point estimate output). For
these reasons, this approach is judged to be superior to the more
common method for assessing risks of non-cancer health effects
which utilizes the reference dose (RfD) methodology. Both the
Guidance Manual and the model are available to Superfund staff
through the Superfund Document Center (703-603-8917) and to the
public through the National Technical Information Service (703-
487-4650).
Residential preliminary remediation goals (PRCs) for CERCLA
remediations and media cleanup s t sl nc3 3 it di s (MCSs) for RCRA
corrective actions can be developed using the IEUBK model on a
site-specific basis, where site data support modification of
model default parameters. At some Superfund sites, using the
IEUBK model with site-specific soil and dust characteristics,
PRGs of more than twice the screening level have been identified.
However, it is important to note that the model alone does not
determine the cleanup levels required at a site. After
considering other factors such as costs of remedial options,
reliability of institutional controls, technical feasibility,
and/or community acceptance, still higher cleanup levels may be
selected.
The implementation of this guidance is expected to provide
for more consistent decisions across the country and improve the
use of sits-specific information for RCRA and CERCLA sites
contaminated with lead. The implementation of this guidance will
aid in determining when evaluation with the IEUBK model is
appropriate and in assessing the likelihood that environmental
lead poses a threat to the public. Use of the IEUBK model in the
context of this guidance will allow risk managers to assess the

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contribution of different environmental sources of lead to
overall blood lead levels (e.g., consideration of the importance
of soil lead levels relative to lead from drinking water, paint
and household dust). It offers a flexible approach to
considering risk reduction options (referred to as the "bubble"
concept) that allows for remediation of lead sources that
contribute significantly to elevated blood lead. This guidance
encourages the risk manager to select, on a site-specific basis,
the most appropriate combination of remedial measures needed to
address site-specific lead exposure threats. These remedial
measures may range widely from intervention to abatement.
However, RCRA and CERCLA have very limited authority to address
interior exposures from interior paint. For a detailed
discussion of the decision logic for addressing lead-contaminated
sites, see the Implementation section and Appendix A.
Relationship to lead paint guidance. In addition, this
interim directive clarifies the relationship between guidance on
Superfund and RCRA Corrective Action cleanups, and EPA1s guidance
on lead-based paint hazards (discussed further in Appendix C),
The paint hazard guidance will be issued to provide information
until the Agency issues regulations identifying lead-based paint
hazards as directed by Section 403 of the Toxic Substances
Control Act (TSCA)2. Lead-based paint hazards are those lead
levels and conditions of paint, and residential soil and dust
that would result in adverse health effects.
The two guidance documents have different purposes and are
intended to serve very different audiences. As a result the
approaches taken differ to some degree. The lead-based paint
hazard guidance is intended for use by any person who may be
involved in addressing residential lead exposures (from paint,
dust or soil.) It thus relates to a potentially huge number of
sites, and serves a very broad potential audience, including
private property owners or residents in addition to federal or
state regulators. Much residential lead abatement may take place
outside any governmental program, and may not involve extensive
site-specific study.
This OSWER guidance, on the other hand, deals with a much
smaller number of sites, being addressed under close federal
regulatory scrutiny, at which extensive site characterization
will have been performed before cleanup decisions are made.
Thus, the RCRA and CERCLA programs will often have the benefit of
much site-specific exposure information. This guidance is
intended for use by the relatively small number of agency
officials who oversee and direct these cleanups.
'Title IV of TSCA (including section 401) was added by the Residential Lead-Based Paint Hazard Reduction
Act of 1992 (Title X of the Housing and Community Development Act of 1992).
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Both the TSCA Section 4 0 3 and OSWER programs use a flexible
tiered approach. The OSWER guidance sets a residential screening
level at 400 ppm. As noted above, this is not intended to be a
"cleanup level" for CERCLA and RCRA facilities, but only to serve
as an indicator that further study is appropriate. The Section
403 guidance indicates that physical exposure-reduction
activities may be appropriate at 400 ppm, depending upon site-
specific conditions such as use patterns, populations at risk and
other factors. Although worded somewhat differently, the
guidances are intended to be similar in effect. For neither
guidance is 400 ppra to automatically be considered a "cleanup
level"; instead, it indicates a need for considering further
action, but not necessarily for taking action. Neither is meant
to indicate that cleanup is necessarily appropriate at 400 ppm.
The greater emphasis in this OSWER guidance on determining the
scope of further study reflects the fact that both CERCLA and
RCRA cleanups proceed in stages with detailed site
characterization preceding response actions in every case.
Above the 400 ppm level, the Section 403 guidance identifies
ranges over which various types of responses are appropriate,
commensurate with the level of potential risk reduction, and cost
incurred to achieve such risk reduction. For example, in the
range of 400 to 5000 ppm, limited interim controls are
recommended depending, as noted above, on conditions at the site,
while above 5000 ppm, soil abatement is recommended. This OSWER
guidance does not include comparable numbers above 400 ppm;
instead, as discussed above, it recommends the site-specific use
of the IEUBK model to set PRGs and MCSs, when necessary. The
remedy selection process specified in the National Contingency
Plan (HOP) should then be used to decide what type of action is
appropriate to achieve those goals.
In general, because the Section 403 guidance was developed
for a different purpose and audience, OSWER does not recommend
that it be used as a reference in setting PRGs and MCSs or in
determining whether action at a particular site is warranted.
(To put it another way, it generally should not be treated as a
"to be considered" document or "TBC" under CERCLA.) The section
403 guidance is meant to provide generic levels that can be used
at thousands of widely varying sites across the nation. The
detailed study that goes on at CERCLA or RCRA sites will allow
levels to be developed that are more narrowly tailored to the
individual site. Nothing in the section 403 guidance discourages
setting more site-specific levels for certain situations; in
fact, it specifically identifies factors such as bioavailability
that may significantly affect the evaluation of risk at some
sites.
The IEUBK nodal. The Agency is further studying both the
IEUBK model and analyses of epidemiologic studies in order to
better develop the technical basis for rulemaking under TSCA
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Section 403. The Agency intends to promulgate regulations under
Section 403 setting health-based standards for lead in soil and
dust. OSWER intends to issue a final soil lead directive once
the TSCA Section 403 regulations are finalized, For additional
information on TSCA Section 403 developments, call (202)
260—1866.
However, the Agency believes that risk managers (risk
assessors, on-scene coordinators, remedial project managers, and
other decision-makers at Superfund and RCRA sites) are currently
in need of the best guidance available today. The Agency
believes that the IEUBK model is the best available tool
currently available for assessing blood lead levels in children.
Furthermore, use of the IEUBK provides allows the risk manager to
consider site-specific information that can be very important in
evaluating remediation options. Therefore, using the latest
developments in the IEUBK model and the collective experience of
the Superfund, RCRA Corrective Action, and TSCA Section 403
programs, the Agency is offering this guidance and is
recommending a residential screening level for Superfund and RCRA
sites of 400 ppm.
BACKGROUND
Earlv OSWER guidance (1989-19911. Four guidance documents on
soil lead cleanup were issued by OSWER during the period of 1989
to 1991:
1.	September 1989, OSWER Directive #9355.4-02. This
guidance recommended a soil lead cleanup level of 500 -
1000 ppm for protection of human health at residential
CERCLA sites.
2.	Hay 9, 1990. RCRA Corrective Action program guidance
on soil lead cleanup. This guidance described three
alternative methods for setting "cleanup levels" (not
action levels) for lead in soil at RCRA facilities.
One approach was to use levels derived from preliminary
results of IEUBK model runs. The other two approaches
were to use the range of 500 to 1000 provided in the
1989 directive on CERCLA sites, or to use "background"
levels at the facility in question.
3.	June 1990, OSWER Directive #9355.4-02A. Supplement to
Interim Guidance on Establishing Soil Lead Cleanup
•levels at Superfund Sites. This memorandum reiterated
that the September 1989 directive was guidance and
should not be interpreted as regulation.
4.	August 29, 1991. This supplemental guidance discussed
EPA's efforts to develop a new directive that would
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accomplish two objectives: (1} account for the
contribution from multiple media to total lead
exposure; and, (2) provide a stronger scientific basis
for determining a soil lead cleanup level at a specific
site.
Development of the IEUBK Model for OSWER use. During the 1989-91
time period, use of the EPA IEUBK model was identified as the
best available approach for accomplishing the objectives outlined
in the August 1991 guidance. The model integrates exposure from
lead in air, water, soil, dust, diet, and paint with
pharmacokinetic modeling to predict blood lead levels in children
(i.e., children 6 to 84 months old), a particularly sensitive
population.
In the spring of 1991, OSWER organized the Lead Technical
Review Workgroup to assist Regional risk assessors and site
managers in both using the model and making data collection
decisions at CERCLA and RCRA sites. The workgroup was composed
of scientists and risk assessors from the Regions and
Headquarters, including the Office of Research and Development
(ORD), and the Office of Pollution Prevention and Toxic
Substances (OPPTS).
In November 1991, the EPA Science Advisory Board (SAB)
reviewed the scientific merits of using the IEUBK model for
assessing total lead exposure and developing soil lead cleanup
levels at CERCLA and RCRA sites. In general, the SAB found the
model to be an important advance in assessing potential health
risks from environmental contaminants. However, the SAB also
recommended additional guidance on the proper use of the model.
In response to SAB concern over the potential for incorrect
use of the model and selection of inappropriate input values both
for default and site-specific applications, OSWER developed a
comprehensive "Guidance Manual for the Integrated Exposure Uptake
Biokinetic Model for Lead in Children" (referred to in this
interim directive as the "Guidance Manual"). This Guidance
Manual assists the user in providing inputs to the model to
estimate risks from exposures to lead. It discusses the use of
model default values or alternative values, and the application
of the model to characterize site risks. Use of the Guidance
Manual should facilitate consistent use of the IEUBK model and
allow the risk assessor to obtain valid and reliable predictions
of lead exposure. The Lead Technical Review Workgroup has been
collecting data to further validate the model and to update the
Guidance Manual as needed.
Relationship to RCRA Corrective Action "Action" Levels. The
approach for calculating a screening level for lead (including
exposure assumptions), set forth in this Revised Interim Soil
Lead Directive, supersedes the guidance provided for calculating
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"action" levels set fortn :r. Appendix D of the proposed Subpart 5
Corrective Action rule. In the July 27, 1990 RCRA proposal (55
Federal Register 30793}, EPA introduced the concept of "action
levels" as trigger levels for further study and subsequent
remediation at RCRA facilities. In this respect, the current
directive's "screening levels" are analogous to the proposed
rule's "action levels." In the proposal, where data were
available, action levels were developed for three pathways of
human exposure to contaminants*, soil ingestion, water ingestion
and inhalation of contaminated air. Exposure assumptions used in
the calculations were set out in Appendix D of the proposal. For
the soil pathway, action levels were calculated two different
ways depending on whether the contaminant in the soil was a
carcinogen or a systemic toxicant. Although lead was listed in
Appendix A of the preamble to the rule as a class B2 carcinogen,
no action level had been calculated because neither a
carcinogenic slope factor (SF) nor a reference dose (RfD) had
been developed by the Agency. Although the guidance in Appendix
D of the proposed Corrective Action rule remains in effect with
respect to other hazardous constituents, this directive now
allows for the development of the lead screening {"action") level
using the IEUBK model.
Recent developments ( 1992-Present). Following discussions among
senior Regional and OSWER management, the OSWER Soil Lead
Directive Workgroup (composed of Headquarters, Regional and other
Federal agency representatives) recommended in the spring of 1992
that a "two step" decision framework be developed for
establishing cleanup levels at sites with lead-contaminated
soils. This framework would identify a single level of lead in
soils that could be used as either the FRG .for CERCLA site
cleanups or the action level for RCRA Corrective Action sites,
but would also allow site managers to establish site-specific
cleanup levels (where appropriate) based on site-specific
circumstances. The IEUBK model would be an integral part of this
framework. OSWER then developed a draft of this directive which
it circulated for review on June 4, 1992. The draft set 500 ppm
as a PRG and an action level for RCRA facilities in residential
settings.
Following development of this draft, OSWER held a meeting on
July 31, 1992 to solicit a broad range of views and expertise. A
wide range of interests, including environmental groups, citizens
and representatives from the lead industry attended. This
meeting encouraged OSWER to think more broadly about how the
directive would affect urban areas, how lead paint and dust
contribute to overall risk, and how blood lead data could be used
to assess risk. In subsequent meetings with the Agency for Toxic
Substances and Disease Control (ATSDR) and the Centers for
Disease Control (CDC), options were discussed on how to use blood
lead data and the need to evaluate the contribution of paint. In
addition, during these meetings, a "decision tree" approach was
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suggested that proposed different threshold levels (primary and
secondary) for screening decisions, action decisions and land use
patterns.
Findings from the three cities (Baltimore, Boston, and
Cincinnati) of the Urban Soil Lead Abatement Demonstration
Project (peer review scheduled for completion in late 1994)
indicate that dust and paint are major contributors to elevated
blood lead levels in children. furthermore, preliminary findings
suggest that any strategy to reduce overall lead risk at a site
needs to consider not only soil, but these other sources and
their potential exposure pathways. (For further information on
this demonstration project, contact Dr. Rob Elias, USEPA/ORD,
Environmental Criteria and Assessment Office (ECAO), RTP, (919)
541-4167.)
Finally, in its efforts to develop this interim directive,
the OSWER Soil Lead Workgroup has met with other EPA workgroups
including the TSCA Section 403, Large Area Lead Sites, and Urban
Lead workgroups, as well as other" Federal agencies including the
Agency for Toxic Substances and Disease Registry, the Centers for
Disease Control, and the Department of Housing and Urban
Development.
Derivation of Lead Screening Levels. Development of the
residential screening level in this interim directive required
two important OSWER decisions. l) OSWER determined that it would
seek to achieve a specific level of protectiveness in site
cleanups; generally, OSWER will attempt to limit exposure to
soil lead levels such that a typical (or hypothetical) child or
group of similarly exposed children would have an estimated risk
of no more than 51 of exceeding the a 10 lead/dl blood lead
level. This 10 iiqldl blood lead level is based upon analyses
conducted by the Centers for Disease Control and EPA that
associate blood lead levels of 10 pg/dl and higher with health
effects in children; however, this blood lead level is below a
level that would trigger medical intervention. 2) In developing
the residential screening level, OSWER has decided to apply the
EPA's IEUBK model on a site-specific basis. This model has been
designed specifically to evaluate exposures for children in a
residential setting. Current research indicates that young
children are particularly sensitive to the effects of lead and
require specific attention in the development of a soil screening
level for lead. A screening level that is protective for young
children is expected to be protective for older population
subgroups.
In general, the model generates a probability distribution
of blood lead levels for a typical child, or group of children,
exposed to a particular soil lead concentration and concurrent
lead exposures from other sources. The spread of the
distribution reflects the observed variability of blood lead
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levels in several communities. This variability arises from
several sources including behavioral and cultural factors.
The identification of lead exposures from other sources {due
to air, water, diet, paint, etc.) is an essential part of
characterizing the appropriate blood lead distribution for a
specific neighborhood or site. For the purpose of deriving a
residential screening level, the background lead exposure inputs
to the IEUBK model were determined using national'averages, where
suitable, or typical values. Thus, the estimated screening level
of 400 ppnt is associated with an expected "typical" response to
these exposures, and should not be taken to indicate that a
certain level of risk (e.g., exactly 51 of children exceeding 10
Mg/dl blood) will be observed in a specific community, e.g., in a
blood lead survey.
Because a child's exposure to lead involves a complex array
of variables, because there is population sampling variability,
and because there is variability in environmental lead
measurements and background levels of lead in food and drinking
water, results from the model may differ from results of blood
lead screening of children in a community. Extensive field
validation is in progress. The model will be evaluated further
once these efforts are completed.
OBJECTIVl
With this interim directive, OSWER recommends using 400 ppm
soil lead {based on application of the IEUBK model) as a
screening level for lead in soil for residential scenarios at
CERCLA sites and at RCRA Corrective Action sites. Residential
areas with soil lead below 400 ppm generally require no further
action. However, in some special situations, further study is
warranted below the screening level. For example, agricultural
areas, wetlands, areas with ecological risk, and areas of higher
than expected human exposure are all situations that could
require further study. For further guidance on ecological risks,
superfund risk managers are encouraged to consult their Regional
Biological Technical Assistance Groups (BTAGs; see Appendix D).
Generally, the ground water pathway will not pose a
significant risk since many lead compounds are generally not
highly mobile. However, there are situations where, because of
the form of lead, hydrogeology, or the presence of other
contaminants at the site, lead may pose a threat to the ground
water. In these situations, additional analysis is warranted,
and the Superfund Regional Toxics Integration Coordinators
(RTICs; see Appendix B) or RCRA hydrogeologists should be
consulted.
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While recognizing that urban lead is a significant problem,
this interim directive is not designed to be applied in
addressing the potential threat of lead in urban areas other than
at cercla or RCRA Corrective Action sites. Guidance and
regulations to be developed under TSCA Section 403 will provide
an appropriate tool for addressing urban sites of. potential
concern.
Generally, where the screening level is exceeded, OSWER
recommends using the IEUBK model during the Remedial
Investigation or the RCRA Facility Investigation for evaluating
potential risks to humans from environmental exposures to lead*
under residential scenarios. Site-specific data need to be
collected to determine PRGs or MCSs. At a minimum, this may
involve collecting soil and dust samples in appropriate areas of
the site. Further guidance on data collection or modification of
the non-residential equation can be obtained by contacting the
RTICs or RCRA Regional risk assessors, who in turn may consult
the Lead Technical Review Workgroup,
The type of site-specific data that should be collected will
obviously depend on a number of factors, including the proximity
of residences to the contaminated soil, the presence of site
access controls, and other factors that would influence the
probability of actual human exposure to the soils. At a minimum,
when residences are at or near the site, it is expected that
using the model will generally involve taking soil and dust
samples from appropriate areas of the site. In many cases, it
may not be necessary to gather certain types of data for input
into the model. For example, when there are no residences
nearby, or where there is otherwise no exposure or very limited
exposure to lead contamination, it nay not be necessary to
collect site-specific data (e.g., dust, water, paint, blood-lead,
etc.)
In developing a PRG for CERCLA sites or a MCS for RCRA
facilities, EPA recommends that a soil lead concentration be
determined so that a typical child or group of children exposed
to lead at this level would have an estimated risk of no more
than 5% of exceeding a blood lead of 10 pg/dl. in applying the
IEUBK model for this purpose, appropriate site specific data on
model input parameters, including background exposures to lead,
would be identified.
When the PRC or MCS is exceeded, remedial action is
generally recommended. Such action does not, however,
necessarily involve excavating soil. A range of possible actions
may be considered, as discussed in greater detail under the
Implementation section of this directive: Issues for Both
Programs.
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implementation
Superf ursd
This interim directive applies to all future CERCLA Remedial
Investigation/Feasibility Study (RI/FS) work; this interim
directive should generally not be applied at sites for which risk
assessments have been completed. For removal sites, this interim
directive recommends that decisions regarding removal actions be
considered first by the Regional Decision Team (RDT). The RDT
will then refer sites to the removal program for early action, as
appropriate.
The approach in this interim directive helps meet the goals
set by the Superfund Accelerated Cleanup Model (SACM) for
streamlining remedial decision-making. (This streamlined approach
is described in Appendix A, Suggested Decision Logic for CERCLA
and RCRA Corrective Action.) This interim directive also
recognizes that other methods (e.g.,	an# athars)-
for evaluating risks at laad sites «ay also* to appropriate*-, ajw
may be used in lieu of, or in conjunction with, the I£UBK*moe intended to address the
multi-media/multi-source nature of environmental lead exposures
because it is expected that people at or near CERCLA and RCRA
Corrective Action sites will experience lead exposures from
sources in addition to contaminated soil. In some instances,
these other exposures may be large 'e.g., where there are
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children living in houses with high levels of lead dust from
deteriorated paint). The presence of various sources of lead
exposure may be very important in both the development of site-
specific risk assessments and in the consideration of alternative
risk management options.
From an assessment perspective, estimating blood lead
levels, that might result from exposures at a site, depends on
appropriately integrating exposures from all relevant media.
Specifically, it is important to consider direct soil exposures
and indoor dust exposures (which can include contributions from
both soil and lead-based paint) on a site-specific basis, as well
as any contributions from drinking water or other local sources
of lead exposure. In using the IEUBK model to estimate blood
lead levels, it is important to note that the risk attributable
to soil lead exposures is dependent upon the existing level of
exposures from other sources. That is, the amount by which the
total risk would be lowered if all exposures to lead in soil were
removed is not a constant, but varies with the level of existing
non-soil exposures. This is because the model derives a
"distribution" (rather than a simple point estimate) as an output
whose shape and size is quite dependent on the predicted
variability of exposures from each lead source. As a result,
other factors being equal, the risks attributable to soil will
generally be higher in the presence of elevated lead exposures
from other sources. Therefore, in applying the IEUBK model, the
risk attributable to soil lead can be predicted as the difference
between the risk estimated when all sources of lead exposure are
assessed, and the risk estimated considering only non-soil
related exposures. This concept is especially important when
evaluating different options for risk reduction at a given site.
From a risk management perspective, achieving a safe
environment for populations at CERCLA and RCRA Corrective Action
sites may require attention to multiple sources of lead, not all
of which may be related to contamination from the source that was
the initial concern at the site. Generally, th& 90&J* ot tha.
Agency, mill i ttmifithi- th» constraints- at C£ACXJfc an# RCRA
legal authosifrie»».±amtm reduce^ to the maximum extent, feasible*,
th«. y *ijgWpif icantiv elsViflf Muur >ead levels. On
a site-specific basis this can include remediatfon approaches
that would lead to reduction of exposure from other sources, such
as lead-based paint, in conjunction with appropriate soil
remediation. Following from the risk assessment discussion in
the previous paragraphs, exposures from lead in soils may have a
lesser impact in producing high blood lead levels if existing
exposures from lead-based paint are reduced.
Abatement vs. Intervention: Remedial measures can be divided
into those that remove the source of contamination (abatement)
and those that leave the contamination in place but block the
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exposure pathway (intervention). These combinations of measures
night include but not be limited to:
Abatement - Soil removal or interior and exterior lead paint
abatement.
Intervention - Institutional controls, education/public outreach,
gardening restrictions, indoor cleaning and dust
removal, or additional cover.
Generally, the most appropriate CERCLA or RCRA response
action or combination of actions will be based, in part, on the
estimated level of threat posed at a given site. However, as
mentioned earlier, key decision criteria also include the overall
protectiveness of response options, attainment of Applicable or
Relevant and Appropriate Requirements (for CERCLA), a preference
for permanent remedies, implementability, cost-effectiveness, and
public acceptance. Intervention measures may be more appropriate
than abatement (e.g., soil excavation) at many sites, especially
in areas where soil lead levels fall at or near the site-specific
PRG or MCS.
. Addressing exposure grow.	Tftli^ Ff TMjjrtffHjr,
risk: to ft- gre**«r eattsnf^M''Vec ME* liuMfmwwfw thaw-girsefly
remediating soil. In some cases, cleaning up the soil to low
levels may, by itself, provide limited risk reduction because
other significant lead sources are present (e.g., contaminated,
drinking water or lead-based paint in residential housing). If
it is possible to address the other sources, the most cost-
effective approach may be to remediate the other sources as well
as, or (if exposures to lead in soil are relatively low) instead
of full soil lead abatement.
Lead-based paint can be a significant source of lead
exposure and needs to be considered when determining the most
appropriate response action. lAfeaciojc	can contribute tQ
eleva.fca«fe.-iiMleasi jinn* Lead 1 evels^i;ri^adri^troo^ex^erior, paint,
caiv a. si
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that would remain from the lead in the soil. In some cases,
after risks from other sources have been addressed, unrestricted
exposure to soil could be allowed while still being protective
(e.g., where the IEUBK model result was heavily affected by the
other sources). In other cases, soil risks may still be high
enough to require abatement, containment or institutional
controls to prevent high levels of exposure. In such cases,
before a conclusion is made that the overall remedy will be
protective, institutional controls should be carefully studied to
make sure that they will be implementable, effective in both the
long-term and short-term, and likely to achieve community
acceptance.
A potentially useful approach that can be considered in
conjunction with other, more active measures in reducing blood
lead levels is to develop and promote public education and
awareness programs that focus on the causes and prevention of
lead poisoning in children. EPA's Office of Pollution Prevention
and Toxics (QPPT) provides information on abatement of lead^based
paint by the homeowner as well as inexpensive preventive measures
the public can take to reduce their exposure to lead. Additional
research to evaluate the effectiveness of educational efforts in
reducing lead exposures are needed to allow better evaluation of
the usefulness of this option. Further, OPPT is assessing the
effectiveness of various lead paint abatement options emphasizing
low-cost methods. For additional information, contact the
National Lead Information Center at 1-800-424-LEAD.
Mining-related sites: Both risk assessors and site managers
should be aware that there are a number of factors that affect
the relationship between soil lead concentrations and blood lead
levels. These factors include the variability in soil lead
contribution to house dust levels, or differences in the
bioavailability of lead. See discussion in next section, Use of
blood lead data, for assessing differences between measured and
predicted blood lead levels.
Thus, for mining-related sites without significant past
smelting/milling activity, this interim directive encourages
further research for characterizing the potential impact of
particle size and speciation on soil bioavailability.
Site managers and risk assessors are cautioned that most
areas impacted by mining activities are also associated with
present or historical smelting or milling operations.
Generalizations regarding distinct differences between mining and
smelting or milling sites should be avoided until adequate site
history and characterization are complete.
Use of blood lead data; In conducting Remedial
Investigations (RIs) for CERCLA or RCRA Facility Investigations
(RFIs) for RCRA Corrective Action, the interim directive
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recommends evaluating available blood lead data. In some cases,
it may be appropriate to collect new or additional blood lead
samples. In general, data from well-conducted blood lead studies
of children on or near a site can provide useful information to
both the risk assessor and site manager. However, the design and
conduct of such studies, as well as the interpretation of
results, are often difficult because of confounding factors such
as a small population sample size. Therefore, any available
blood lead data should be carefully evaluated by EPA Regional
risk assessors to determine their usefulness. The Guidance
Manual discusses how to evaluate observed blood lead survey data
and blood lead data predicted by the IEUBK model.
The Guidance Manual recommends that blood lead data not be
used alone either to assess risk from lead exposure or to develop
soil lead cleanup levels. During its review of the IEUBK mziel,
the SAB supported this position by asserting that site residents
may temporarily modify their behavior (e.g., wash their
children's hands more frequently) whenever public attention is
drawn to a site. In such cases, this behavior could mask the
true magnitude of potential risk at a site and lead to only
temporary reductions' in the blood lead levels of children. Thus,
blood lead levels below 10 ^g/dl are not necessarily evidence
that a potential for significant lead exposure does not exist, or
that such potential could not occur in the future.
Non-residential (adult) screening level. EPA also believes
there is a strong need to develop a non-residential (adult)
screening level. The IEUBK model is, however, not appropriate
for calculating this screening level since it is designed
specifically for evaluating lead exposures in children. At this
time, EPA is considering a few options for developing this
screening level. Several adult models have recently become
available. Developing a screening level by using any of then is
likely to require significant additional work by the Agency.
This work might include testing, validation, and selection of one
of the existing models or development of its own model, both of
which would require a considerable amount of time. Consequently
this would probably be a long-term option. A short-term option
would be to develop a screening level based on a simple approach
that approximates the more complicated biokinetics in humans.
This can serve in the interim while more sophisticated adult lead
exposure assessment tools can be identified or developed.
NOTICE; Users of this directive should bear in mind that the
recommendations in this document are intended solely as guidance,
and that EPA risk managers may act at variance with any of these
recommendations where site-specific conditions warrant, as has
been noted above. These recommendations are not intended, and
cannot be relied upon, to create any rights, substantive or
procedural, enforceable by any party in litigation with the
United States, and may change at any time without public notice.
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Because this document and the related Guidance Manual are
not legally binding either upon EPA or other parties. Agency
personnel should keep in mind if they are questioned or
challenged in comments on a proposed remedial plan, such comments
must be considered and a substantive explanation must be provided
for whatever approach is ultimately selected. For example, while
the IEUBK model is recommended here, its use is not a regulatory
requirement and comments on the model or its use should be fully
cons idered.
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APPENDICES
A suggested Decision Logic for CERCLA and RCRA Corrective
Action
A-l Suggested Decision Logic for Residential Scenarios for
CERCLA and RCRA Corrective Action
A-2 Suggested Decision Logic for Lead-based Paint for
CERCLA and RCRA Corrective Action
B Regional Toxics integration Coordinators (RTXCS)
c Relationship between the oswer Soil Lead Directive and
TSCA Section 4 03 Guidance
D Biological Technical Assistance Group coordinators (BTAGS)
A-l
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Appendix A-1
Suggested Decision Logic for Residential Scenarios
for CERCLA and RCRA Corrective Action
Step l: Determine soil lead concentration at the site.
If soil lead is less than 400 ppm:
STOP, no further action is required, UNLESS special
circumstances (such as the presence of wetlands, other
areas of ecological risk, agricultural areas, shallow
aquifers, or other areas of potentially high exposure)
warrant further study.
If soil lead is greater than 400 ppn:
PROCEED to Step 2, UNLESS 4 00 ppm is selected as a
cleanup goal based on consideration of all relevant
risk management factors.
Step 2: Evaluate probable land use and develop exposure
scenarios.
Step 3; Collect appropriate site-specific data based on
selected scenarios.
For example, sampling data may include:
Soil and dust (at a minimum), paint, water, and
air
For unique site situations, data on speciation and
particle size, and behavioral activities may be
required.
Available blood lead data:
If blood lead data are available, consult the
Guidance Manual and Regional Risk Assessor.
If blood lead data are not available, Regional
Risk Assessors and site managers should consider
the appropriateness of conducting a blood lead
study to supplement available data.
Step 4: Run the IEUBK model with site-specific data to estimate
risk and evaluate key exposure pathways at the site.
If blood lead data are available, compare the data
to the model results
Step 5: Where risks are significant, evaluate remedial options.
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If lead-based exterior or interior paint is the only
major contributor to exposure, no Superfund action or
RCRA corrective action is warranted.
If soil is the only major contributor to elevated blood
lead, a response to soil contamination is warranted,
but paint abatement is not.
If both exterior lead-based paint and soil are major
contributors to exposure, consider remediating both
sources, using alternative options as described in
Appendix A-2.
If indoor dust levels are greater than soil levels,
consider evaluating the contribution of interior
lead-based paint to the dust levels. If interior
lead-based paint is a major contributor, consider
remediating indoor paint to achieve a greater overall
risk reduction at lower cost. (See Appendix A-2.)
NOTE: Available authority to remediate lead-based paint
under CERCLA and RCRA is extremely limited.)
Step 6; If the IEUBK model predicts elevated blood leads, rerun
the model using the site-specific parameters selected
to reflect remedial options in Step 5 to determine
site-specific PRGs or MCSs for soil.
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Appendix A-2
Suggested Decision Logic for Lead-based Faint
for CERCLA and RCRA Corrective Action
(If soil lead levels are below screening levels, lead-based
paint could be addressed by authorities other than RCRA or
CERCLA.)
If soil lead levels are above screening levels:
Step 1. Examine condition of exterior paint and determine
its lead content, if any.
If paint is deteriorated, assess contribution
or potential contribution of paint to
elevated soil lead levels through speciation
studies, structural equation modelling, or
other statistical methods.
Step 2, Evaluate potential for recontamination of soil by
exterior paint.
Step 3. Remediate exterior paint only in conjunction with
soil.
Determine appropriate remediation based on
risk management factors (e.g., applying the
nine criteria), remediating the major
contributor first.
Step 4. Examine condition of indoor paint and determine
its lead content, if any.
If indoor dust lead concentration is greater
than outdoor soil lead concentration (because
of contamination from both interior paint and
outdoor soil), remediate indoor dust (e.g.,
through a removal action, or making HEFA-VACS
available to community).
Step 5. Once the risk from indoor paint has been assessed,
examine options to abate indoor paint (e.g., PRP,
State, local, HUD) and consult TSCA Section 403
program for additional information and/or
guidance.
Step 6. While RCRA and CERCLA have very limited authority
regarding the cleanup of interior paint, the
remedy may take into account the reduction of
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total risk that may tceur if interior paint is
addressed by other weans. Thus, for example, a
Record of Decision (ROD) or Statement of Basis
(SB) may recognize that interior lead-based paint
is being addressed by other means, and narrow the
response accordingly (possibly making this
contingent on completion of the interior lead-
based paint abatement effort.
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Appendix 8
Superfund Regional Toxics integration Coordinators (RTICs)
Te Leohona	ihX
Ann-Marie Burke	617/223-5528	617/573-9662
EPA Region 1 HSS-CAN-7
John F, Kennedy Federal Sldg.
Boston, MA 02203
Peter Crtvatt	212/264-6323	212/264-6119
EPA Region 2
26 Federal Plaza
Mew York, N* 10278
Reggie Harris	215/597-6626	21S/597-3150
SPA Region 3 (3HM15 j
841 Chestnut. Street
Philadelphia, PA 19107
Dr. Elmer Akin	404/347-1586	404/347-0076
EPA Region 4
34S Courtland St, NB
EPA 9452
Atlanta, CA 30365
Erin Moran	312/353-1420	312/386-0753
EPA Region 5 HSRLT-5J
77 West Jackson Street
Chicago, II 60604
Jon Rauscher
EPA Region 6 6H-SR
lit Interst. Bank Tower
1445 Rosa Ave.
Dallas, TX 75202
214/655-8513
214/655-6460
David Crawford (Acting)
EPA Region 7 Superfund
726 Minnesota Ave.
Kansas City, XS 66101
Chris weis
EPA Region 8 8HWM-SR
999 18th St. Suite 500
Denver, CO 80202
Dan stralka
EPA Region t ORA
75 Hawthorne Street
San Francisco, CA 94105
913/551-7702
303/294-7655
415/744-2310
913/551-7063
303/293-1230
415/744-1916
Carol Sweeney	206/553-6699	206/553-0119
EPA Region 10 ES-098
1200 6th Avenue
Seattle, WA 98101
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Appendix C
Relationship between the OSWER Soil Lead Directive
and TSCA Section 403 Guidance
Since lead exposures occur through all media, a variety of
Agency programs address lead under a number of statutes. Lead in
soil is addressed under TSCA Section 403, the RCRA Corrective
Action program, and CERCLA, each of which differs somewhat in the
types of sites that apply and the types of standards that are
used. These differences are primarily due to differences in the
purposes of the programs and the authority granted by the
statutes under which they are developed. Section 403 soil
standards will apply only to residential soil and the current
TSCA guidance is generic in nature, with the same standards
applying on a nationwide basis. Given the wide applicability of
Section 403, generic standards are used in the current guidance
in order to reduce resource requirements, as compared to site-
specific decisions which can involve expensive and time-consuming
analyses. Required RCRA and CERCLA activities are determined on
a site-specific basis. The agency's recommendations for
evaluating RCRA corrective Action and CERCLA sites are contained
in the oswer Interim Soil Lead Directive,
In all three of these programs, the Agency's approach is to
consider soil lead in the context of other lead sources that may
be present and contribute to the total risk. For example, TSCA .
Section 403 specifically requires the Agency to consider the
hazards posed by lead-based paint and lead-contaminated interior
dust, as well as lead-contaminated soil. Likewise, the OSWER
Soil Directive includes evaluation of other lead sources at a
site as part of site assessment/investigation procedures. In
addition, the primary focus of the three programs is primary
prevention — the prevention of future exposures from the
source(s) being remediated.
The fundamental difference between the relatively new TSCA
Section 403 program and the RCRA Corrective Action and CERCLA
cleanup programs is that, under current guidance the Section 403
program seeks to establish national standards to prioritize
responses to lead hazards whereas the other two programs usually
develop site-specific cleanup requirements. This is because TSCA
Section 403 deals with a potentially huge number of sites, and
resources for the investigation needed to accurately identify
their risks are typically very limited. Therefore most decisions
under Section 403 will be made with little or no regulatory
oversight and clear generic guidelines will be more effective.
The more established RCRA and CERCLA programs, on the other hand,
deal with a much smaller number of sites, at which extensive site
characterization will have been performed before cleanup
decisions are made. In addition, these programs have well-
established funding mechanisms.
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Appendix D
suparfund Biological Technical Assistance Group Coordinators

Teleahone	r»
David Charters	908/906-6826	908/321-6724
Mark Sprenger
ERT
'JSEPA (MS -101)
2890 Woodbridge Ave., Bldg, 13
Edison, NJ 08837-3679
Jeffrey Langholx	703/603-8783	703/603-9103
TIB
USEPA (5204G>
401 M Strut SW
Washington, DC 20460
Suian Svirsky	617/573-9649	617/573-9662
Waste Management Division
USEPA Region 1 (HSS-CAN7)
JFK Federal Building
Boston, HA 02203
Shari Stevens	908/906-6994	908/321-6616
Surveillance Monitoring Branch
USEPA Region 2 (HS-220)
Woodbridge Avenue
Raritan Depot Building 209
Edison, NJ 08837
Robert Davia	215/597-3155	215/597-9890
Technical Support Section
USEPA Region 3 (3HW15)
841 Chestnut Street
Philadelphia, PA 19107
Lynn Welima*	404/347-1586	404/347-0076
WSMD/HERAS
USEPA Regies 4
345 Courtland Street, Ml
Atlanta, GA 30365
sileen Helmer	312/886-4828	312/886-7160
USEPA Region 5 (HSRLT-5J)
77 west Jackson Boulevard
Chicago, IL 60604-1602
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Appendix D (Continued)
suparfund Biological Technical Assistance Group Coordinators
(STAGS)
Jon Rauichar	214/655-8513	214/655-6762
Suaan Swanaon Roddy
CSEPA Ration 6 (6H-SR)
Fir¦t Intaratata Towar
1445 Rosa Avanua
Dallas, TX 75202-2733
Bob Koka	913/551-7463	913/551-7063
SPFD-RJSML
USEPA Ragion 7
726 Minnaaota Avanua
Xmtaa City, KS 66101
Carry Hanningaan	303/294-7656	303/293-1230
USEPA Ragion 8
Oanvar Placa, Suita 500
999 18th Straat
Oanvar, CO 80202-2405
Doug Staala	415/744-2309	415/744-1915
USEPA Ragion 9
75 Hawthorna Straat
San Francisco, CA 94105
Bruca Duncan	206/513-8086	206/553-0119
DSIiA Ragien 10 (ES-09S)
1200 6th Avanua
Seattla, HA 98101
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