The
NEW ENGLA ND JOURNAL
of
MEDICINE
Perspective
March 24, 2016
Lead Contamination in Flint — An Abject Failure to Protect
Public Health
David C. Bellinger, Ph.D.
Lead Contamination in Flint
T
he dangers of lead exposure have been recognized for millennia. In the first century a.d.,
Dioscorides observed in his De Materia Medica
that “lead makes the mind give way.” The first in-
dustrial hygiene act passed in the
colonies, in 1723, prohibited the
use of lead in the apparatus used
to distill rum, because “the strong
liquors and spirits that are distilld
through leaden heads or pipes are
judged on good grounds to be
unwholsom and hurtful.” More
recently, large amounts of lead
were used to boost the octane
rating of gasoline and improve
the performance of paint. One
would be challenged to design a
better strategy for maximizing
population exposure to a poison
than to have it emitted by a ubiquitous mobile source and to line the
surfaces of dwellings with it.
The dramatic reduction over the
past 40 years in blood lead levels
in the U.S. population is rightly
regarded as one of the cardinal
public health success stories. It
was achieved largely by phasing
out lead as a gasoline additive and
restricting the amount of lead permitted in paint. At the same time,
because of research opportunities
created by reductions in population exposures, the consensus view
on how much lead is “too much”
has also evolved. It is now established that there is no safe level
of lead, particularly for children.
The reference blood lead concentration for children set by the
Centers for Disease Control and
Prevention, 5 μg per deciliter, is
meaningful only for risk stratification.
n engl j med 374;12
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Water doesn’t receive as much
attention as paint as a route of
lead exposure, but the use of lead
in water-distribution systems goes
back to the Romans. Indeed, our
word “plumbing” derives from the
Latin for lead, and lead poisoning
is often called “plumbism.” The
recent episode in Flint, Michigan,
has brought the issue of lead in
water into the public eye.
In 2014, solely as a cost-saving
measure, the city began taking its
water from the Flint River rather
than Lake Huron. The corrosioncontrol treatments required by the
Environmental Protection Agency’s
Lead and Copper Rule1 were, for
some reason, discontinued. To
make matters worse, the addition
of ferric chloride to reduce the formation of trihalomethanes from
organic matter increased the corrosivity of the Flint River water.
The water reaching consumers
was therefore 19 times as corrosive
March 24, 2016
The New England Journal of Medicine
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1101
Lead Contamination in Flint
PERS PE C T IV E
as it had been when the source
was Lake Huron. The more corrosive water is, the more readily
it can dissolve metals such as
lead. So the lead concentration in
Flint’s water began to rise. In six
of nine city wards, the water in
20 to 32% of the homes had a
lead concentration above 15 μg
per liter, a concentration that triggers remedial action under the
Lead and Copper Rule. The 90th
percentile was 25 μg per liter,
and in some samples the concentration exceeded 1000 μg per
liter (www.FlintWaterStudy.org).
fants’ dietary intake of lead ranges
from 0.2 to 0.9 μg per kilogram
of body weight per day, so a 5-kg
infant typically takes in about
2.5 μg per day.3 If, however, the
infant consumes 1 liter of water
per day with a lead concentration
of 25 μg per liter, the intake of
25 μg of lead would be 10 times
higher day after day.
Lead contamination of drinking water poses a particular public health challenge because it
rarely originates in the source
water. Rather, the problem usually lies near the point of consump-
The burden of childhood lead poisoning
has always weighed most heavily on
populations that are politically
and economically disenfranchised.
This contamination had consequences. Hanna-Attisha et al.
reported that among children in
Flint, the incidence of blood lead
concentrations above the reference
value of 5 μg per deciliter rose
from 2.4% to 4.9% between 2013
and 2015.2 The increase was
greatest, from 4.0% to 10.6%,
among children in neighborhoods
with the highest lead concentrations in water.
Children are more vulnerable
to lead than adults because of
their greater fractional absorption of ingested lead and greater
intake on a body-weight basis
and because development of the
central nervous system is easily
derailed in ways that result in cognitive and behavioral abnormalities. When lead concentrations in
water are high, infants consuming reconstituted formula are at
special risk. The European Food
Safety Authority estimates that in-
1102
tion, in lead service pipes connecting the house to the water
main or lead pipes, lead solder,
or lead brass fixtures in the home.
Large-scale contamination generally occurs when changes are
made in water-treatment protocols without consideration of the
effect of those changes on the
amount of lead that will leach
from these materials. A decade
ago in Washington, D.C., a change
from the use of free chlorine to
chloramine to reduce disinfection
by-products caused such a problem, and lead contamination of
water has recently occurred in
some new housing in Hong Kong
because, against code, plumbers
used lead solder.
The burden of childhood lead
poisoning has always weighed
most heavily on populations that
are politically and economically
disenfranchised. In Flint, 4 in 10
families live below the poverty
n engl j med 374;12
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line, unemployment is high, and
the majority of the population is
black. In general, disadvantaged
children are exposed to more lead
than their wealthier counterparts
because they are more likely to
live in houses in poor repair that
still harbor deteriorating lead
paint, to live in urban neighborhoods with greater soil and dust
lead concentrations from traffic
and industrial activities, and to
have nutritional deficiencies that
increase lead absorption. An elevated water lead concentration
therefore adds to a background
exposure that is already high. Indeed, Hanna-Attisha et al. showed
that even before the water contamination began, the incidence of
blood lead concentrations above
5 μg per deciliter was more than
three times as high among children in Flint as among children
in neighboring municipalities.2
Were Flint more affluent, it’s
unlikely that the contamination
would have continued for 18
months after citizens first voiced
complaints about water quality.
An institutional factor that
probably contributed to the crisis
is that Flint was in receivership
because of severe financial difficulties. The decision to switch
water suppliers was made by a
state-appointed emergency manager rather than local officials,
who might have been better positioned to make a decision reflecting concern for public health as
well as the bottom line. Although
the cost of repairing Flint’s water
infrastructure is uncertain, estimates range as high as $1.5 billion. The cost of reducing the
corrosivity of the Flint River water
at the time of the change would
have been minimal, perhaps $100
per day4 — proving again that
prevention is generally cheaper
March 24, 2016
The New England Journal of Medicine
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Copyright © 2016 Massachusetts Medical Society. All rights reserved.
Lead Contamination in Flint
PE R S PE C T IV E
brought to light had citizens not
persisted in efforts to force local,
state, and federal officials to take
action. This is not the way public
health protection should work,
and the crisis appears to reflect
failures at every level of government. In 1969, environmentalist
René Dubos warned that the
problem of childhood lead poisoning “is so well-defined, so neatly
packaged, with both causes and
cures known, that if we don’t
eliminate this social crime, our
society deserves all the disasters
that have been forecast for it.”5
We have yet to fully respond to
Dubos’s admonition.
We have the knowledge required to redress this social crime.
We know where the lead is, how
people are exposed, and how it
damages health. What we lack
is the political will to do what
should be done.
than remediation and treatment.
More money will be spent in the
courts, since multiple lawsuits
have already been filed. Imagine
what could have been achieved
for the people of Flint if the
funds that will now be needed to
repair the damage and litigate
lawsuits could instead have been
used to pursue goals such as improving the schools, de-leading
homes, or funding programs providing job training, early education, or treatment and prevention
for substance abuse
An audio interview
with Dr. Bellinger
or domestic abuse.
is available at NEJM.org
Other costs that can
be anticipated include developmental surveillance and treatment of the thousands of affected children. In coming years,
parents will undoubtedly wonder, with anxiety and even guilt,
whether their children’s every developmental stumble stems from
this episode.
It is notable that the Flint contamination might never have been
Disclosure forms provided by the author
are available with the full text of this article
at NEJM.org.
From the Departments of Neurology and
Psychiatry, Boston Children’s Hospital and
Harvard Medical School, and the Department of Environmental Health, Harvard
T.H. Chan School of Public Health — all in
Boston.
This article was published on February 10,
2016, at NEJM.org.
1. National primary drinking water regula-
tions for lead and copper: short-term regulatory revisions and clarifications. Federal
Register. October 10, 2007 (https:/
/
w ww
.federalregister.gov/a rticles/2007/10/10/
E7-19432/national-primary-drinking-water
-regulations-for-lead-and-copper-short-term
-regulatory-revisions-and-clarifications).
2. Hanna-Attisha M, LaChance J, Sadler
RC, Champney Schnepp A. Elevated blood
lead levels in children associated with the
Flint drinking water crisis: a spatial analysis
of risk and public health response. Am J
Public Health 2016;106:283-90.
3. European Food Safety Authority. Scientific opinion on lead in food. EFSA 2010;8:
1570 (http://www.efsa.europa.eu/sites/default/
files/scientific_output/f iles/main_documents/
1570.pdf).
4. Poisoned water. That Flinty taste. Economist 2016;418(8973):23.
5. Oberle MW. Lead poisoning: a preventable childhood disease of the slums. Science
1969;165:991-2.
DOI: 10.1056/NEJMp1601013
Copyright © 2016 Massachusetts Medical Society.
Lead Contamination in Flint
Mitochondrial Replacement Techniques
Mitochondrial Replacement Techniques — Implications
for the Clinical Community
Marni J. Falk, M.D., Alan Decherney, M.D., and Jeffrey P. Kahn, Ph.D., M.P.H.
M
itochondrial DNA (mtDNA)
diseases may be the poster
child for highly targeted, “personalized” medicine. These heterogeneous disorders, although rare
individually, have well-defined
genetic causes — more than 400
known pathogenic mutations or
deletions in the 16,569-base-pair
mitochondrial chromosome that
contains only 37 genes. Affected
persons may present at any age
with some combination of severe,
often progressive, and sometimes
fatal neurologic, musculoskeletal,
cardiac, gastrointestinal, renal,
ophthalmologic, and audiologic
involvement. No cures or therapies have been approved by the
Food and Drug Administration
(FDA) for any mtDNA disease,
although symptom-based clinical
management can be beneficial.
Despite their precisely defined
causes, it’s often difficult to predict the onset or severity of these
diseases because of heteroplasmy:
the culprit mtDNA mutation is
n engl j med 374;12
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commonly present in only a fraction of the body’s mitochondria.
Building on the principle that less
is better, reducing mutant heteroplasmy loads below an often
tissue-specific and difficult-todefine threshold presents a potential opportunity to improve health
that is unique to these diseases.
Research in animal and somatic
cellular models has focused on
this potential, using endonuclease, TALEN (transcription activator–like effector nuclease), or
March 24, 2016
The New England Journal of Medicine
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Copyright © 2016 Massachusetts Medical Society. All rights reserved.
1103
Vol. 58 / RR-9
Recommendations and Reports
1
Recommendations for Blood Lead Screening of Medicaid-Eligible
Children Aged 1–5 Years: an Updated Approach to Targeting a
Group at High Risk
Anne M. Wengrovitz, MPH, Mary Jean Brown, ScD
Advisory Committee on Childhood Lead Poisoning, Division of Environmental and Emergency Health Services, National Center for Environmental Health
Summary
Lead is a potent, pervasive neurotoxicant, and elevated blood lead levels (EBLLs) can result in decreased IQ, academic failure,
and behavioral problems in children. Eliminating EBLLs among children is one of the 2010 U.S. national health objectives. Data
from the National Health and Nutrition Examination Survey (NHANES) indicate substantial decreases both in the percentage of
persons in the United States with EBLLs and in mean BLLs among all age and ethnic groups, including children aged 1–5 years.
Historically, children in low-income families served by public assistance programs have been considered to be at greater risk for
EBLLs than other children. However, evidence indicates that children in low-income families are experiencing decreases in BLLs,
suggesting that the EBLL disparity between Medicaid-eligible children and non–Medicaid-eligible children is diminishing. In
response to these findings, the CDC Advisory Committee on Childhood Lead Poisoning Prevention is updating recommendations
for blood lead screening among children eligible for Medicaid by providing recommendations for improving BLL screening and
information for health-care providers, state officials, and others interested in lead-related services for Medicaid-eligible children.
Because state and local officials are more familiar than federal agencies with local risk for EBLLs, CDC recommends that these
officials have the flexibility to develop blood lead screening strategies that reflect local risk for EBLLs. Rather than provide universal
screening to all Medicaid children, which was previously recommended, state and local officials should target screening toward
specific groups of children in their area at higher risk for EBLLs. This report presents the updated CDC recommendations and
provides strategies to 1) improve screening rates of children at risk for EBLLs, 2) develop surveillance strategies that are not solely
dependent on BLL testing, and 3) assist states with evaluation of screening plans.
Introduction
Substantial improvements have been made in reducing lead
in the environment. During 1999–2004, 1.4% of children
in the United States aged 1–5 years had elevated blood lead
levels (EBLLs) (1), compared with 8.6% of children during
1988–1991. Despite this progress, some children remain at
risk, and eliminating EBLLs among all children aged 1–6
years is a 2010 national health objective (objective 8–11) (2).
To meet this objective, the limited available resources must be
focused on the populations at highest risk for EBLLs. Since
1989, children who are eligible for Medicaid have been identified as having an increased risk for lead exposure. This finding
forms the basis for the current national Medicaid policy, which
targets Medicaid-eligible children for preventive and screening
measures, including routine blood lead testing. However, evidence from several states indicates that children in low-income
families are experiencing decreases in BLLs. This underscores
the need for closer analysis of the lead risk patterns within variCorresponding preparer: Mary Jean Brown, ScD, Division of
Environmental and Emergency Health Services, National Center
for Environmental Health, CDC, 4770 Buford Highway, MS F-40,
Atlanta, GA 30341. Telephone: 770-488-7492; Fax: 770-488-3635;
E-mail: mjb5@cdc.gov.
ous jurisdictions and suggests that children who are eligible for
Medicaid can no longer be assumed to have an increased risk
for EBLLs. Therefore, a new blood lead screening strategy is
needed that accounts for local variations in risk and disparities
at the local level. This report reviews available data on childhood lead exposure in the United States, especially among
children aged 1–5 years who are eligible for Medicaid, updates
screening recommendations for this population, and describes
relevant Medicaid program requirements and changes.
The national objective to eliminate EBLLs among children
by 2010 is part of a larger national goal to eliminate health
disparities among various segments of the population (Goal 2)
(2). Improved blood lead screening policies and practices also
support the “healthy people in healthy places” component of
CDC’s core health protection goals, which aim to promote and
protect health through safe and healthy home environments
(3). In 2000, CDC, the Department of Housing and Urban
Development (HUD), the Environmental Protection Agency
(EPA), and other agencies developed a federal interagency
strategy to eliminate EBLLs among children by 2010. An
important element of this interagency strategy is identification
and care of children with EBLLs, especially Medicaid-eligible
children (4).
2
MMWR
Methods
The National Health and Nutrition Examination Survey
(NHANES) is an ongoing series of cross-sectional surveys
on health and nutrition designed to be nationally representative of the noninstitutionalized, U.S. civilian population by
using a complex, multistage probability design. All NHANES
surveys include a household interview followed by a detailed
physical examination. NHANES data indicate substantial
decreases since 1976 in both the percentage of persons in the
United States with EBLLs and in mean BLLs among all age
and ethnic groups.
The CDC Advisory Committee on Childhood Lead
Poisoning Prevention (ACCLPP) makes recommendations
to improve lead poisoning prevention measures. In 2001, in
response to the decreased prevalence of EBLLs in the United
States, ACCLPP formed a workgroup to 1) review the published research regarding screening of children at high risk for
EBLLs and 2) outline recommendations for state Medicaid
agencies to determine whether risk for lead exposure among
Medicaid-eligible children overall is higher than for non–
Medicaid-eligible children in their jurisdictions. The Centers
for Medicare & Medicaid Services (CMS), which is the administrator of the Medicaid program, reviewed the recommendations developed by the workgroup. The recommendations were
approved by ACCLPP in September 2008.
Blood Lead Levels and Exposure
Patterns Among Children
Lead has been associated with numerous adverse health
effects in humans (5). In children, even BLLs 20 µg/dL were Medicaid eligible (16). A
subsequent analysis of all 1988–1994 NHANES data found
that families who reported having Medicaid coverage were
more likely to have EBLLs than those who were not enrolled
in Medicaid (16). Such findings supported a focus on identifying cases of EBLL among Medicaid children to provide early
intervention and treatment and develop focused prevention
strategies (17). Medicaid eligibility, as well as eligibility for
other programs for low-income families, is a proxy for poverty
and therefore for living in old, poorly maintained housing,
which is more likely to contain lead paint hazards.
As a result of increased lead screening for Medicaid children,
recent data are available that provide a more detailed characterization of this population’s risk for EBLLs. An analysis
of Minnesota data indicated that the percentage of tested
children aged
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