● No measurable level of blood lead is known to be without deleterious effect. In 2012, the Centers
for Disease Control and Prevention (CDC) established a new “reference level” for blood lead levels
5, thereby lowering the level at which evaluation and interventions (public health and
clinical) are recommended.
● The National Toxicology Program and U.S. Environmental Protection Agency’s (US EPA) Lead
Integrated Science Assessment both concluded that adverse underdevelopment cognitive impacts
occur at blood lead levels less than 5. New findings also suggest that the adverse health
effects of chronically elevated blood lead levels (BLLs) extend beyond cognitive effects to include
cardiovascular, immunologic, reproductive, developmental, and endocrine effects. Clinically overt
effects such as anemia, abdominal pain, nephropathy, and encephalitic may occur at BLLs as low
as 45 and are more likely as BLLs increase.
● Lead paint and contaminated dust/soil are the highest dose sources of lead for US children.
● US EPA estimates that drinking water can make up 20 percent or more of a person’s total
exposure to lead. The contribution of exposure to lead from drinking water can be higher for
young infants who consume mostly mixed formula.
At-Risk Populations:
● Children less than six years old, including the developing fetus, are especially vulnerable to health
problems from lead exposure.
○ As defined by the CDC, children who are members of racial-ethnic minority groups, live in
poverty, in substandard housing, are recent immigrants, and have parents exposed to
occupational sources of lead are disproportionately at higher risk of lead exposure.
● Formula-fed infants who are exposed to lead through contaminated tap water are at higher risk
because they consume large volumes of formula relative to their body size. Lead levels in breast milk
tend to be low; breast milk is highly nutritious and the best choice for most babies.
● Water may be an important source of lead exposure in some communities with lead service lines
and unsatisfactory corrosion control. A study conducted by Hanna-Attisha et al. indicates that as
much as 50% of lead intake was from water during a 14-month exposure window in Flint, Michigan.
What factors affect how much lead gets into drinking water?
Type of plumbing materials:
● Homes built before 1986 are more likely to have
pipes, fixtures, or solder that contain lead.
Newer homes may also present a risk: until
recently, approved “lead-free” plumbing fixtures
may have contained up to 8% lead. As of January
2014, changes to the Safe Drinking Water Act
have further reduced the maximum allowable
lead content of pipes, pipe fittings, and plumbing
fittings to 0.25%.
● Lead can be included in plumbing materials from
the water service main to the property line
and/or to the internal household plumbing
(Figure 1).
● Families can identify if they have a lead service line by inspecting their own plumbing, hiring a
plumber, or calling their water provider. Lead service lines are generally a dull gray color that are
very soft and are easily scratched with a key.
● Construction and repair work on supply and distribution lines can increase water lead content.
● Corrosives of water: Lead can enter drinking water through corrosion of plumbing materials,
especially where the water has high acidity or low mineral content.
● Length of time water stands in pipes: Lead can build up in tap water when water stands in the pipes
for an extended duration, such as for six hours or longer.
How do I counsel a family about identifying if lead is in their drinking water?
● The US EPA regulates lead in public water supplies with more than 50 customers under the Safe
Drinking Water Act Lead and Copper Rule, which requires certain actions by municipal water utilities
when more than 10% of customer taps sampled have a lead concentration that exceeds 15 parts per
billion (ppb). The 15 ppb action level is an administrative tool to evaluate and mitigate community
level exposure; it is not a health-based standard.
● Clinicians should recommend families learn more about the water coming into their home. US EPA
requires all community water systems to prepare and deliver an annual drinking water quality
report entitled Consumer Confidence Report for their customers (http://www.epa.gov/ccr).

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