Table 2.1. Summary of Recommendations for Assessment and Remediation of Residential Lead Exposure
Make
prompt and effective environmental management for children with
EBLLs the highest priority of all childhood lead poisoning
prevention programs. 1. Conduct an environmental investigation for all children with blood lead levels >=20 µg/dL, or persistently $15 µg/dL. This investigation should include: |
||
a. | An inspection of the child’s home and other sites where the child spends significant amounts of time. | |
b. | A history of the child’s exposure | |
c. | Measurements of environmental lead levels, including at a minimum | |
i. | House dust; | |
ii. | Paint that is not intact or is subject to friction; | |
iii. | Exposed soil, especially in play areas; | |
iv. | Other media as appropriate; | |
2. Ensure that interventions to reduce ongoing exposure: |
||
a. | Focus on control of current lead hazards. | |
b. | Include prompt interim measures (e.g., house dust control by professional cleaners) where appropriate, to rapidly reduce lead exposure. | |
c. | Be performed in accordance with safe practices by trained workers to avoid increasing lead exposure to occupants and workers. | |
d. | Keep to a minimum on-site removal of intact leaded paint. | |
e. | Replace or enclose building components when elimination of intact leaded paint is performed. | |
f. | Include
clearance testing following lead hazard reduction work to ensure that lead levels are safe prior to a structure being re-occupied. |
|
g. | Include temporary occupant relocation or other measures to protect occupants from exposure to leaded dust produced by lead hazard control activities. | |
h. | Relocate children permanently to lead-safe housing if necessary to reduce their lead exposure in a timely manner. | |
3. Encourage state and local governments to assess the effectiveness of their laws, ordinances, housing codes, and enforcement structures in dealing with identified lead hazards and to identify changes required to ensure that children are protected. |
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4. Promote the expansion of existing federal, state, and local subsidies to help finance lead hazard control in economically distressed communities, and the creation of new subsidies, if necessary. |
Recent
research concerning lead exposure from leaded paint in the residential
environment has shown that some of the recommendations on managing lead
hazards in the child’s environment made in the 1991 Centers for
Disease Control and Prevention (CDC) guidance, Preventing Lead
Poisoning in Young Children, need updating (1). In
addition, a regulation to control lead exposure from public drinking
water (2), implemented during the
1990s, makes possible a more focused approach to assessing that source
than was previously recommended. This chapter summarizes current
knowledge concerning children’s lead exposure in the residential
environment, recommends interventions directed at reducing or
eliminating lead exposure, and provides information to guide state and
local officials in developing and updating policies and procedures for
identifying and managing lead hazards in the residential environment of
children with elevated blood lead levels (EBLLs).
Detailed technical protocols for
assessing and correcting lead hazards in a variety of situations can be
found in guidance developed by the Department of Housing and Urban
Development (HUD) for property owners, private contractors, and
government housing agencies (3). These are cited where
appropriate.
Sources and pathways of residential lead exposure
Lead can be found in high concentrations in three media to which children may be directly or indirectly exposed: paint, interior dust, and exterior soil or dust. This section discusses the distribution of lead in these media and their relationships to one another and to blood lead levels (BLLs) in children (Figure 2.1). Lead in tap water, generally a lower dose source of exposure, is also addressed.
Paint
Although the addition of lead to residential paint and similar surface-coating materials, such as varnishes and stains, was banned in 1978 (4), 74% of dwellings constructed prior to 1980 contain some leaded paint.* The amount of lead in paint is much greater in homes built before 1950 than in homes built later but prior to the ban on leaded house paint. For example, 90% of dwellings built before 1940 have paint
---------------------------------------
*Throughout this
document, the term "paint" will be used to refer to paint and,
where appropriate, similar surface-coating materials such as varnishes and
stains. Paints and coatings manufactured since 1978 must contain < 0.06%
lead by weight. For testing of lead content in existing structures, the
regulatory threshold for defining "lead-based paint" is $1
milligram of lead per square centimeter of paint film or $0.5 % lead by
weight. These standards, however, were based on the limitations of
measurement techniques available when they were formulated rather than on
health considerations.
----------------------------------------
containing more than 1
mg/cm2 of lead, compared with 62% of dwellings built from 1960
through 1979. The relative contrast is much greater for paint containing
more than 2 mg/cm2: 75% versus 18%, respectively (5).
Direct and indirect exposure of children to leaded paint that has
deteriorated because of deferred maintenance is likely the major factor in
the increased risk for EBLL associated with poverty and living in older
housing. Data from the Third National Health and Nutrition Examination
Survey (NHANES III) indicate that the prevalence of EBLLs among children
living in homes built before 1946 is five times higher than that among
children living in homes built after 1973 (most of which do not have leaded
paint) (6). Furthermore, for low-income children living in pre-1946
dwellings, the prevalence of EBLLs is 16%, compared with 4% for
middle-income children living in such dwellings (6).
Although children may be exposed to
lead from paint directly by ingesting paint chips (7), they are more
commonly exposed by ingesting house dust or soil contaminated by leaded
paint (8, 9). Federal law defines a leaded paint hazard as a
condition in which exposure to lead from lead-contaminated dust,
lead-contaminated soil, or deteriorated leaded paint would have an adverse
effect on human health (10).
Lead contamination of dust or soil
occurs when leaded paint deteriorates or is subject to friction or abrasion
(as on window sashes). In addition, lead can be dispersed when paint is
disturbed during demolition, remodeling, paint removal, or preparation of
painted surfaces for repainting. In a population-based study in Wisconsin,
about two-thirds of children who had a blood lead test lived in a home that
had undergone some type of renovation, repair, or remodeling work in the
prior year. These children were at 1.3 times greater risk of having an EBLL
than were children not exposed to such activities (11). The risk was
even higher among children living in homes where certain practices, such as
the removal of paint with heat guns, had been used.
Interior dust
Interior house dust can
become contaminated with lead as the result of the deterioration or
disturbance of leaded paint, the tracking or blowing in of contaminated
soil, and the fallout of airborne lead particulate from industrial or
vehicular sources. A simple visual inspection of older homes can identify
those in poor condition. The condition of leaded paint more accurately
predicts lead exposure than the lead content of paint by itself (12, 13).
Older homes in poor condition have much higher dust lead levels than older
homes in good condition (Figure 2.2) (14). The amount of lead in
house dust, in turn, has a strong correlation with the BLLs of young
children (12, 13, 15, 16) and is more predictive of BLLs
in children than is the amount of lead in house paint (13). Lead
levels in house dust can be measured either as a mass concentration (mass of
lead/mass of dust) or as surface loading (mass of lead per surface area
sampled). The most widely used sampling technique,
in which a wipe sample is collected with commercially available baby wipes (3),
can determine only lead surface loading. However, this measure predicts
BLLs as well as or better than mass concentration (17). Lead loadings
vary considerably among the
types of surfaces commonly tested, with levels on interior window sills and
window "wells" (the part of the window that receives the lower
sash when closed) often being, respectively, 1 and 2 orders of magnitude
higher than those found on floors. Higher levels on window components may
reflect a combination of lead dust derived from friction and the
deterioration of leaded paint on the windows themselves and from the
settling of airborne dust from outside of the dwelling. Dust lead loading on
all three surfaces (floors, windowsills, and window wells) correlates with
BLLs in children (12).
A recent statistical analysis of data
from 12 studies relating lead in dust to BLLs in children between 6 and 36
months of age found a strong direct association between dust lead
loading and the risk of having an EBLL (13). The
association extended well below the 40 µg/ft2 threshold for a
lead hazard in dust samples collected from floors as defined by HUD
(18) and the Environmental Protection
Agency (EPA) (19). For example, the estimated
probability of a child having an EBLL increases from 7% to 18% with an
increase in floor dust lead loading from 10 to 40 µg/ft2 (Figure
2.3) (13). For dust samples collected from window sills,
lead levels >=250 µg/ft2 are defined as hazardous (18, 19).
Soil and Exterior Dust
Contamination of soil and exterior dust has been linked to point source
emissions, such as lead smelters, fall-out from past use of leaded gasoline,
and weathering of exterior leaded paint (20). Soil located next to
dwellings typically has higher lead content than that sampled from other
locations in a yard.
Potentially hazardous levels of lead in soil are not uncommon. Results of a
national survey in which soil samples were collected from both bare and
covered soil showed that residences with intact exterior leaded paint are
more than three times as likely to have soil lead levels exceeding 500 ppm
than are dwellings without lead in exterior paint (21% vs. 6%). Results also
showed that soil contamination is eight times more common at residences with
non-intact leaded exterior paint than at residences without exterior leaded
paint (48% vs. 6%) (5). In urban neighborhoods, high levels of lead
have also been found in exterior dust collected from paved surfaces, such as
sidewalks (21).
Soil lead content is an important predictor of children’s risk for an EBLL,
though less important than the lead content of interior floor dust (13).
Soil samples taken from play areas in a yard have a stronger relationship to
children’s BLLs than samples from other locations. The EPA defines a soil
lead hazard as bare soil that contains 400 ppm of lead in a play area
or 1200 ppm in other parts of a yard (19).
Tap water
Lead found in tap water
usually is from the corrosion of lead-containing materials found in water
distribution systems and household plumbing (22). Exposure to lead in
tap water has been reduced by measures taken during the last two decades
under the requirements of the 1986 and 1996 amendments to the Safe Drinking
Water Act and a subsequent EPA regulation (the Lead and Copper Rule) (2).
The latter regulation, which only applies to public water systems, requires
those systems to monitor tap water for lead and to implement public
education and other measures to reduce lead levels in drinking water if they
exceed 15 µg/L in more than 10% of household samples (2). Lead
levels are reduced by treating the supplied water to make it less corrosive
and, in some cases, by replacing lead water-service lines. These regulations
do not apply to the more than 40 million households supplied by private well
water that can have elevated levels of lead if the water is corrosive and
lead is present in the well pump or household plumbing system (23).
In most jurisdictions, there is no monitoring for lead in the drinking
water supplied by private wells.
A number of studies, mostly
of adults, have attempted to characterize the relationship between lead
levels in drinking water and BLLs (24-26). Data from these studies
indicate that exposure to water with a lead content close to the EPA action
level would not, by itself, be expected to produce an EBLL. However, the
individual risk will vary depending upon the circumstances and amount of
water consumed. For example, infants consuming formula prepared with
lead-contaminated water may be at particular risk because of the large
amount of water they consume relative to their body size (27).
Effectiveness and Safety of Lead Hazard Control Measures
Interventions to reduce exposure to lead in the residential environment
include measures focused on immediate hazards to current occupants, such
as removing or covering nonintact leaded paint, repairing or replacing
windows to prevent abrasion of leaded paint on moving surfaces, sealing
floors to create smooth and cleanable surfaces, using professional
cleaners to control household dust, and covering bare, contaminated soil.
Additional interventions may be carried out to prevent lead hazards from
developing in the future, such as replacing building components that have
leaded paint (whether intact or not) and removing (stripping) leaded paint
from components left in the dwelling.
Most
studies evaluating the effectiveness of lead hazard control measures for
reducing EBLLs have lacked controls. In addition, many studies evaluated
interventions prior to the institution of stringent procedures for
limiting the contamination of residences with leaded dust. In general,
these earlier studies showed that among children with baseline BLLs
greater than about 25 µg/dL, measures to remove or repair nonintact
leaded paint were followed by declines in BLLs of 20% to 30% over the
following year (28). In one controlled study, the decline in BLLs
for children in treated dwellings was about twice that of children in
untreated dwellings (29).
In homes of children with EBLLs, extensive
removal of leaded paint without measures to prevent the children’s
exposure to abatement dust and debris has also been associated with
increases in the children’s BLLs (30-32). These increases were
apparently the result of corresponding increases in house dust lead
levels. Consequently, regulations in many jurisdictions now prohibit
certain hazardous paint removal methods, such as uncontained power
sanding, and require safe work practices, cleaning, and dust lead testing
to protect occupants from lead exposure associated with the disturbance of
leaded paint. Most jurisdictions require that post-intervention dust lead
levels be below clearance standards—the maximum allowable levels of
lead. If the dust lead levels in a particular dwelling exceed the
clearance standard, that dwelling cannot be reoccupied until additional
cleaning or other measures reduce dust lead contamination to less than the
clearance threshold. Clearance standards for public and federally assisted
housing are 40 µg/ft2 for floors,
250 µg/ft2 for windowsills, and
400 µg/ft2 for window wells. Some
state and local jurisdictions have established other clearance standards (19).
Recent longitudinal studies have
evaluated leaded paint abatement programs that combined multiple lead
hazard control methods (33-35). Interventions used in these
programs included measures to prevent the generation of leaded paint chips
and dust (treatments to eliminate nonintact leaded paint and windows
containing leaded paint subject to friction), leaded dust removal
(specialized cleaning), and measures to make floors smooth and cleanable
(by sealing or using durable floor coverings). The elimination of leaded
paint hazards in the programs relied primarily on component replacement,
enclosure, and paint stabilization, with limited on-site paint removal.
Although these studies did not include randomly assigned control homes
that received no treatment, their results strongly suggest that these
treatments resulted in substantial, sustained reductions in interior dust
lead loading and little if any risk of children having substantial
short-term increases in BLLs. While average BLLs in children occupying
treated dwellings fell by approximately 20% to 25% over the following year
(from baseline averages in the 5-15 µg/dL
range) (35), no data on children in untreated dwellings are
available to directly estimate the proportion of decline attributable to
the hazard-reduction treatments. In one of these studies, greater initial
and sustained reductions in interior dust lead loadings were achieved with
more intensive treatments, including window replacement (rather than
repair) and the use of durable floor coverings (rather than paints and
sealants) (34). However, among children living in the more
intensively treated dwellings, average BLL declines following the
intervention were not significantly greater than those among children
whose dwellings had more limited interventions.
These
studies generally involved interventions that left some intact leaded
paint in place. The only certain way to prevent future exposure to lead
from paint in a dwelling is to remove all leaded paint from the dwelling.
However, no studies are available that compare changes in children’s
BLLs following the total "deleading" of their dwelling with
changes following interventions that leave some leaded paint intact. If
many components in a dwelling contain leaded paint, complete deleading may
be impractical unless performed as part of a substantial or
"gut" renovation.
One study of children with baseline
BLLs of 10 to 24 µg/dL found that leaded
paint hazard-control measures, including extensive on-site paint removal,
resulted in increases in children’s BLLs after abatement (36).
These increases occurred despite a protocol for safe work practices,
cleaning, and clearance testing. However, the clearance standard used for
floors was 200 µg/ft2, which may
have been too high to prevent continued or increased exposure to leaded
dust when compared with pre-intervention levels. The previously cited
impact of relatively "low" levels of lead in house dust on
children’s BLLs could explain the increases.
Interventions focused on reducing
exposure to leaded dust have been evaluated in several studies (37-39).
Household dust control performed repeatedly by professional cleaners was
associated with decreases in children’s mean BLL with the greatest
benefits seen among children whose dwellings were cleaned at least 20
times during a 1-year follow-up period (38). To be effective, dust
control should be conducted every 2-3 weeks. However, simply educating
parents about the need to perform dust control as a preventive measure has
not proven effective in preventing increases in children’s mean BLLs (39).
See Chapter 6, "Educational Interventions for Caregivers," for a
detailed discussion of the effects of such education.
In a controlled study, soil removal
and replacement with uncontaminated soil was associated with a 15%
reduction in BLLs among children whose average baseline BLL was from 10 to
24 µg/dL and who were exposed to high
levels of lead in soil (40). Two other studies of the lead
abatement of soil with lower baseline contamination showed no reduction in
children’s BLLs following such abatement (21, 41).
In the studies noted above and
reviewed in detail in Chapter 6, the benefits of environmental
interventions have generally been modest—BLL reductions in the range of
10% to 30%. A number of factors might explain the limited
effectiveness of these interventions. One such factor is that the
interventions were limited in scope: lead hazard control often involved
the interior but not the exterior of homes. Another factor is that most
interventions were performed in scattered rather than contiguous blocks of
homes. Thus, children’s continued exposure to lead from sources in the
neighborhood might limit the effectiveness of the interventions. In the
Baltimore repair and maintenance study, for example, one comparison group
consisted of modern urban homes located in contiguous blocks of such
dwellings that were built where older row homes with leaded paint once
stood. The geometric mean level of lead contamination in the floor dust of
the modern urban homes was less than one-tenth that of older homes that
had previously undergone complete lead paint abatement but which were
still surrounded by other homes with leaded paint. The geometric mean BLL
for children living in the modern homes was one-fourth that of the
children living in the older homes (34). A final factor is that the
release of lead from bone might also reduce the impact of environmental
interventions. By one estimate, an intervention reducing total lead
exposure by half for a 5-year-old child would, because of mobilized bone
lead stores, cause the child’s BLL to decline by only 25% after 1 year (42).
Recommendations for Assessment and Remediation
General Recommendations
Conduct prompt and effective environmental management.
The identification
and control of ongoing sources of lead exposure for children with EBLLs
should be the highest priority. In addition, identifying children with
EBLLs may help officials identify and control potential sources of lead
exposure for other children. Because the main objective of environmental
management is to reduce lead exposure quickly, investigations should be
initiated as soon as possible after a case is identified.
Priority should be placed on
responding to children with the highest BLLs and to infants and children
less than 2 years of age with any EBLL, because their BLLs are more likely
to increase and they are more sensitive to lead’s neurotoxic effects.
Table 2.2 shows the recommended maximum time frames for initiating
environmental investigations and interventions according to a child’s
BLL.
Obtain an exposure history. Investigations
to identify sources of a child’s lead exposure should begin with an
interview with the child’s caregiver. Whenever possible, the interview
should take place at the child’s residence. The interviewer should
question the caregiver concerning a range of possible exposure sources.
(See Table 2.3 and Appendix I.) It is also important to collect
information concerning locations outside the home, such as childcare
sites, where the child spends significant amounts of time. The interview
should be guided by a checklist tailored to sources of lead exposure found
in a given jurisdiction. Checklists facilitate data collection and ensure
that potential sources are not overlooked. A sample checklist is provided
in Chapter 3, "Medical Assessment and Interventions," and in the
1995 HUD guidelines (3).
Visually inspect the residential
environment. A visual inspection can quickly identify areas where
deteriorating paint may be contributing to lead exposure and should
include windows, porches, bare soil, and common areas in multifamily
dwellings, as well as any other locations where the child spends time.
Measure lead in environmental
media. Selection of the media to be tested should be guided by
the visual inspection and the child’s exposure history. Depending on the
inspector’s training, the equipment available, and the media to be
tested, environmental analysis may be done either on-site with portable
instruments or at an environmental laboratory. Personnel performing
environmental sampling and on-site testing should be appropriately trained
and be certified as risk assessors (43) or have equivalent
qualifications.
Communicate results. Results
of investigations, including recommended actions to protect the child from
further exposure, should be communicated promptly to caregivers, to
primary care providers (PCPs), and, where relevant, to property owners and
housing code enforcement authorities. Environmental management activities
should be coordinated with other health professionals, including those
providing clinical care, case management, and social services.
Specific Recommendations
Since leaded paint and
associated lead in house dust and soil are the most common sources of
exposure, they should be the focus of environmental investigations and
control efforts. State and local health officials should review current
policies concerning childhood lead poisoning prevention and revise them as
needed to be consistent with the following recommendations.
Measure lead levels in house dust,
paint, and bare soil. Investigations of the residential environment of
children with EBLLs should focus on immediate lead hazards. At a minimum,
testing should include house dust, paints, and similar surface coatings
that are not intact or that are located on surfaces subject to friction,
and bare soil, especially in play areas. Detailed protocols for sampling
and measuring lead in these media can be found in the 1995 HUD guidelines
(3).
There is no evidence that complete
testing of all building components for leaded paint, regardless of the
condition or location of the paint, is helpful in identifying ongoing
exposure. Such testing may serve other purposes, however, such as
educating occupants about the health hazards of leaded paints, planning
the abatement of potential future leaded paint hazards, planning
renovation work that may involve disturbance of intact paint, or complying
with state and local regulations.
Test for lead in tap water. For homes
served by public water systems, data on lead in drinking water should be
obtained from the water supplier. Many public water systems post data on
the Internet on the quality of drinking water, including results of lead
testing. Links to such data can be found at the following EPA Web site:
http://yosemite.epa.gov/ogwdw/ccr.nsf/America?OpenView.
If prior testing of a public water system shows that lead contamination is
not a problem in homes served by that system, no additional testing is
necessary, unless no other source of a child’s EBLL can be found. For
all other children with EBLLs, including children living in homes served
by private wells, water that the child may consume should be tested. If
necessary, measures should be implemented to prevent the child’s further
exposure to lead (e.g., the use of bottled water or appropriate water
filters). If bottled water is used, fluoride supplementation should be
discussed with the PCP and the caregiver. More information on lead in
drinking water can be found at http://www.epa.gov/ogwdw/dwh/o-ioc/lead.html
or by contacting the Safe Drinking Water hotline at (800) 426-4791 or
hotline-sdwa@epamail.epa.gov. Additional sources of information about lead
in drinking water can be found in Chapter 6, "Educational
Interventions for Caregivers."
Control immediate hazards. Interventions to reduce ongoing exposure should include:
Lead hazard control work must be performed in accordance with safe
practices by trained workers to avoid exposing workers to unsafe lead
levels or increasing the level of lead exposure to occupants. Detailed
guidelines for residential lead hazard control work have been published by
HUD (3).
On-site
removal of intact leaded paint should be kept to a minimum, and safer
alternatives, such as component replacement, enclosure, encapsulation,
off-site paint removal, and paint-film stabilization should be used when
possible. Replacing building components that have intact leaded paint
reduces the potential for future lead exposure as the leaded paint
deteriorates or is disturbed during renovation. However, such work can
generate leaded dust, and workers should follow the precautions described
in HUD guidelines.
As discussed previously, there is no
evidence that environmental interventions that include complete removal of
all leaded paint are more effective at reducing residents’ BLLs than
interventions focused on current lead hazards. Furthermore, some evidence
suggests that extensive on-site paint removal increases the potential for
lead exposure, at least in the short run. The amount of lead in 1 ft2
of paint containing 1 mg/cm2 of lead (approximately 1 g or
1 million Fg) is very large relative to the amount of lead in
dust associated with an increased risk for EBLLs (approximately 10 µg/ft2).
Thus, performing extensive on-site removal of leaded paint in a dwelling
without increasing the occupants’ lead exposure requires a degree of
caution that may be difficult to achieve and monitor in the routine,
large-scale implementation of health codes.
Long-term control of residential
hazards from leaded paint may involve considerable time and expense.
Obtaining the compliance of property owners may cause additional delays in
reducing residents’ lead exposure. Therefore, interim measures to
rapidly reduce lead exposure, including specialized cleaning to reduce
exposure to leaded dust, are often required.
Perform clearance testing.
Following lead hazard reduction work, repeat testing for lead in house
dust is essential to see whether the work has resulted in levels of lead
low enough for safe re-occupancy. Post-intervention tests showing
increased or persistently high dust lead levels indicate the need for
further cleaning or other additional work. Available evidence indicates
that current and proposed guidelines for levels of lead in dust on floors
may not adequately protect young children and that levels well below these
guidelines are achievable and are often present even before intervention.
Therefore, the goal should be to attain post-intervention dust lead levels
that are as low as is feasible, which is generally less than 10 µg/ft2
on floors (44), and that are at or below baseline levels. Where
leaded paint is left in place, periodic monitoring with visual inspection
and dust testing should be performed.
Relocate occupants. Temporary
occupant relocation is generally required to safely conduct lead hazard
control activities that may increase dust lead levels. In some cases, it
may be feasible to protect occupants during lead control activities by
creating barriers, monitoring the work site daily, and, where appropriate,
obtaining serial dust lead measurements. In other cases, permanently
relocating occupants to lead-safe housing may be the best way of quickly
reducing their lead exposure. Examples of situations that might require
relocation include a child living in a dwelling that is structurally
unsound or a child living in a dwelling where temporary measures to reduce
exposure cannot be taken or are ineffective. Case managers and social
workers with experience in assisting families with housing difficulties
can play a vital role in assessing the needs and desires of the family and
arranging such relocation. A registry of lead-safe housing units in a
community can also be helpful. When families permanently relocate from a
dwelling where lead hazards are identified, measures should be taken to
ensure that the hazards are corrected before any other families with young
children occupy the dwelling.
Enforcement of Laws and Regulations
Although enforcing laws and regulations pertaining to lead hazards is not part of case management per se, it is essential to realizing the long-range goal of reducing those hazards. Individual states should provide health and housing officials with the necessary legal authority to require that timely and effective actions are taken to eliminate lead hazards at properties where children with EBLLs have been identified. Health and housing officials should take all steps necessary to prevent additional or repeated cases of children with EBLLs at one property. In a recent national survey, only 18 states indicated that they have legal authority to order remediation at properties where children with EBLLs reside, with only 14 states reporting that their authority was based on lead-specific state laws or regulations (45). State and local governments should examine their laws, ordinances, and housing codes and their enforcement structure to determine whether they are effective in dealing with identified lead hazards and make changes to ensure that children are protected. At a minimum, legislation or ordinances should include the action level at which the law applies, procedures for investigation and re-inspection, standards for lead-safe housing, requirements for completing lead hazard control work (including permits, time frames, permissible methods, waste disposal methods, and clearance standards) and enforcement provisions for noncompliance. In addition, states and localities should be encouraged to develop lead-safe housing standards to protect children from exposure and to ensure that older rental housing is safe for children with EBLLs. Finally, state and local governments should also ensure that they have the ability and necessary resources to take emergency actions (including cleaning the rental units, stabilizing the paint in them, and relocating the occupants) to protect children from identified lead hazards.
Financial Resources for Lead Hazard Control
Many of the homes in which children with EBLLs live are poorly maintained,
deteriorated, low-income rental properties. For some economically
distressed housing, subsidies and other financial assistance for lead
hazard control are required to enable owners to make timely corrections of
residential lead hazards. Because resources for addressing lead hazards,
particularly in low-income housing, are inadequate in most areas of the
country, an increase in resources at the federal, state, and local level
should be strongly supported.
In addition, state and local health
agencies should develop strong partnerships with local housing and
community development organizations, investigate currently available
resources for improving low-income housing, and establish mechanisms to
apply such resources to lead hazard control in homes of children with
EBLLs. A detailed discussion and recommendations concerning financing of
lead hazard control work can be found in a HUD publication (46). Some
examples of current programs providing resources for this purpose are
provided in the following paragraphs.
HUD’s Lead Hazard Control Grant
Program (47) enables state or local agencies to provide grants or loans to
property owners for conducting lead hazard control measures in low-income
housing. Federal regulations require the timely identification and
remediation of lead hazards in federally assisted housing, including
rental property, whose owners receive tenant-based assistance (Section 8
housing) (19). This program should create a growing pool of lead-safe
housing in the future. Decisions on specific priorities for tenant
selection under Section 8 and for public housing have been devolved to
state and local public-housing agencies. This local flexibility gives
health departments in jurisdictions where lead exposure is a major problem
an opportunity to urge that priority for assistance be given to families
of children with the highest BLLs who are unable to find or afford
lead-safe housing.
State and local governments can use
HUD’s Community Development Block Grant (CDBG) and HOME Investment
Partnership block grant funds to make housing lead-safe. The resources
available for state and local block grants under these programs ($6.4
billion in FY 2000) dwarf the $60 million available under the Lead Hazard
Control Grant Program. Both the CDBG and HOME programs provide a high
degree of flexibility in the use of funds. Indeed, CDBG funds are used by
some jurisdictions to support emergency programs dealing with problems
such as the breakdown of plumbing or heating systems. A similar approach
would be desirable for controlling lead hazards.
State and local governments receiving
these block grants must submit a consolidated plan (ConPlan) containing a
5-year strategic plan and a 1-year action plan for their use of these and
other available funds. The strategic plan must include actions to evaluate
and reduce leaded paint hazards and describe how hazard reduction will be
integrated into other housing activities. Evaluating and reducing leaded
paint hazards is also a required component of the annual action plan. HUD
regulations require that eligible jurisdictions consult with state or
local health and child welfare agencies as well as health and social
service providers as part of the planning process. State and local health
departments with identified lead problems should involve themselves in
this planning process to ensure that lead hazard control is a priority for
federal CDBG and HOME funding.
Recommendations for Future Research
Technical knowledge concerning the identification and control of lead
hazards in homes has advanced greatly over the past several years,
resulting in more efficient, safe, and effective environmental management
for children with EBLLs. Still, prevention efforts could be improved with
further work in several areas.
Additional studies are needed to
assess the long-term impact of current lead hazard control methods on
children’s EBLLs, especially on levels from 10 to 20 µg/dL. Available
data indicate that these methods are safe and effective (i.e., they do not
increase children’s BLLs in the short run and they decrease children’s
exposure to leaded dust). Because BLL changes over time may be influenced
by a child’s age, the season, and secular trends, as well as by
regression to the mean, controlled studies are needed to determine how
much of the observed decline in BLLs among children living in these
dwellings can be attributed to the interventions. Future research should
also evaluate the cost effectiveness of interventions.
Until recently, most residential lead
hazard control work and studies have involved children who already had
EBLLs and presumably relatively high body stores of lead from chronic
exposure. The effectiveness of residential lead hazard control in
preventing future increases in BLLs among infants and toddlers needs
further study.
The level of neighborhood lead
exposures appears to make an important contribution to the risk for EBLLs
among children. Research is needed to examine how community-level lead
sources, such as lead from building demolitions, contribute to children’s
exposure. Finally, the effectiveness of community-level interventions to
reduce children’s exposure to lead in dwellings and in exterior dust and
soil should be further studied.
Figure 2.1. Pathways of Lead Exposure in the Residential Environment
Sources: Bornschein et al., 1987 (reference 8). Lanphear et al., 1997 (reference 9)
Figure. 2.2. Relationship
of Housing Age and Condition to Dust Lead Levels
Source: Clark et al., 1985 (reference 14)
Figure 2.3. Relationship of Dust Lead Levels to Blood Lead Levels in Children
Source: Lanphear et al., 1998 (reference 12). Assumes children are exposed to a soil lead concentration equal to the national average level (72 ppm).
Table 2.2. Time Frames for Environmental Investigation and Other Case Management Activities According to a Child’s Blood Lead Levela
Blood lead level µg/dL)b |
Actions |
Time frame for beginning intervention |
10-14 |
Provide caregiver lead education. Provide follow-up testing. Refer the child for social services if necessary. |
Within 30 days |
15-19 |
Above
actions, plus: If BLLs persist (i.e., 2 venous BLLs in this range at least 3 months apart) or increase, proceed according to actions for BLLs 20-44. |
Within 2 weeks |
20-44 |
Above
actions, plus: Provide coordination of care (case management). Provide clinical evaluation and care.c Provide environmental investigation and control current lead hazards. |
Within 1 week |
45-70 |
Above actions. |
Within 48 hours |
70 or higher |
Above actions, plus hospitalize child for chelation therapy immediately. |
Within 24 hours |
aThe ACCLPP encourages programs to develop methods to deliver environmental assessment services to caregivers for children living in high-risk dwellings regardless of the children’s blood lead levels. bMicrograms per deciliter of whole blood measured in a venous sample collected following an elevated screening measurement. cThe recommended clinical evaluation is described in Chapter 3, “Medical Assessment and Interventions.” |
Table
2.3. Common Sources of Lead Exposure to Consider in an Environmental
Investigation
(less common sources should be considered where appropriate—see
Appendix I)
Source |
Standardsa/Comments |
References |
Paint |
New
paint: 600 ppm in dried paint film.Existing paint in structures
built prior to 1978: 1 mg/cm2 or 0.5%
Hazard is increased if leaded paint is deteriorated; present on surfaces subject to friction (e.g., window sashes); or disturbed during maintenance, repair, and renovation, especially during surface preparation for repainting. |
3, 4 |
Interior dust |
Floors:
40 micrograms per square foot µg/ft2)b Interior window sills: 250 µg/ft2 Window troughs: 400 µg/ft2 Research shows children to be at increased risk for EBLLs at floor lead loading substantially below standard. |
18, 19 |
Residential soil |
Bare
play area soil: 400 ppm All other soil: 1200 ppm Dust on paved surfaces in urban areas often contains elevated lead concentrations. |
19 |
Drinking water |
First
draw from tap (stagnant sample): 15 ppb
Probability of contamination depends on the chemistry of the water. For communities served by public water systems, available data may indicate whether testing is likely to be helpful. |
2 |
Occupations, hobbies |
House dust may be contaminated with lead (see above) indirectly via contaminated work clothes, shoes, or hair. Direct contamination can occur from hobbies that generate lead fumes (from heating) or dust. |
47 |
aNote: Most standards for lead in environmental media are established on the basis of measurement feasibility or for primary prevention purposes. These standards cannot be used to determine the cause of an EBLL, which requires that environmental measurements be interpreted in the context of a careful exposure history.
bEPA has established standards of 40 and 250 µg/ft2for hazardous levels of lead in dust on floors and sills, respectively. HUD has established interim standards, 25 and 125 µg/ft2, that apply if a more limited assessment known as a "lead hazard screen" is performed. The EPA standard for window troughs is intended only for clearance testing after lead hazard reduction activities.