Lead is a naturally occurring metal that can cause learning and behavior problems in children if they are exposed to it. In rare cases, it can even be fatal. Experts have not found any safe blood lead level, which means even low lead exposure can have adverse or long-term effects.
In 2017–2018, US adults 20 years or older had the highest average concentration of lead in their blood, followed by children ages 1 to 5. People between the ages of 12 and 19 years old had the lowest blood lead levels.
The Centers for Disease Control and Prevention (CDC) measured the blood lead levels of National Health and Nutrition Examination Survey (NHANES) participants in 2017–2018, the latest period reported to date.
The NHANES found that 95% of adults 20 years or older had lead levels of 2.62 micrograms per deciliter (µg/dL) or lower. In comparison, 95% of people between ages 12 and 19 had lead levels less than half that amount at 1.09 µg/dL or lower.
Blood lead levels decreased in American adults and children from 2011 to 2018, according to the NHANES data. The 2011–2012 survey found that 95% of Americans had blood lead levels of 3.16 µg/dL or less. The 2017–2018 survey showed that this number was 2.41 µg/dL or less, a 0.75 µg/dL decrease.
According to the CDC, most unintentional lead exposure occurs by breathing in lead dust, eating lead paint chips from homes or buildings built before 1978, or ingesting water from lead pipes or contaminated food. Other sources of lead poisoning include imported toys and jewelry and soil from nearby airports, highways, or factories. Jobs and hobbies that involve lead products, such as stained glass work, can also cause lead poisoning.
Children younger than 6 are more likely to be at risk for lead poisoning because they frequently put objects, such as contaminated toys, in their mouths.
Lead exposure can adversely affect children’s health: brain and nervous system damage, slowed growth and development, learning and behavior problems, and hearing and speech issues. These effects can manifest in lower IQ, a decreased ability to pay attention, and underperformance in school.
The CDC identifies five factors that determine how a child may react to lead exposure or consumption:
Once ingested, lead is stored in the bloodstream and bones and may take decades to decrease. According to the CDC, lead exposure can have the most harmful effects on children under six because their bodies grow rapidly during this time.
The Environmental Protection Agency (EPA) analyzed data on children’s blood levels from the CDC and found that the median concentration of lead in the blood of children between the ages of one and five years decreased by 96% from 15 µg/dL in 1976–1980 to 0.6 µg/dL in 2017–March 2020.
Additionally, the concentration of lead in blood at the 95th percentile in children in this age group decreased by 93% from 29 µg/dL in 1976–1980 to 2.1 µg/dL in 2017–March 2020. This concentration is less than the CDC’s blood lead reference value of 3.5 µg/dL, used to identify children with abnormally high blood lead levels.
The largest drop in children’s blood lead levels occurred between the 1970s and 1990s with the elimination of lead from gasoline. Blood lead levels continued to decline between 1999–2000 and 2017–March 2020 due to a national effort to reduce lead-based paint in homes.
The Government Accountability Office (GAO) published a report in December 2020 that found common lead sources in drinking water within US homes were faucets, copper pipes with lead solders, and lead service lines. Neighborhoods with older housing and vulnerable populations — such as families in poverty — had higher concentrations of lead service lines and a higher risk of lead in the water.
Most of the data comes from the CDC and its survey NHANES. The last chart showing state data comes from CDC childhood blood lead surveillance data, which the CDC compiles based on blood test data collected by state and local health departments and reported to the CDC.
According to the CDC, while NHANES is the best source for nationally representative, population-based prevalence estimates of elevated blood lead levels in US children, the data does not represent an entire state or county. Additionally, because many children are not at risk for lead exposure, they do not receive a blood test, which can create a bias in the data.
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