Biomonitoring - Perchlorate
Perchlorate is a naturally occurring and man-made chemical that is used to make fireworks, explosives, flares, and rocket fuel. It has been detected in groundwater, surface water, soil, and some foods, including dairy products and infant formula.
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Indicator
B12: Perchlorate in women
Key Information
- In 2017-2020, the median level of perchlorate in urine of women of child-bearing age was 2.2 µg/L, a decrease from 3.3 µg/L in 2001-2002. The median represents the midpoint of exposure.
- In 2017-2020, the 95th percentile level of perchlorate in the urine was 8.2 µg/L, a decrease from the highest level of almost 17 µg/L in 2007-2008. The 95th percentile represents higher exposure.
Data Characterization
Data for this indicator are obtained from an ongoing continuous survey conducted by the National Center for Health Statistics.
Survey data are representative of the U.S. civilian noninstitutionalized population.
Perchlorate is measured in urine samples obtained from individual survey participants.
B13: Perchlorate in children
Key Information
- In 2017-2020, the median level of perchlorate in children’s urine was about 2.9 µg/L, a decrease from about 4.9 µg/L in 2001-2002.
- Perchlorate exposure tends to decrease with age. In 2017-2020, the median level of perchlorate in children’s urine was over 25% higher than the level in women’s urine, suggesting that on average children are more exposed to perchlorate. In addition, younger children had higher levels than older children.
Data Characterization
Data for this indicator are obtained from an ongoing continuous survey conducted by the National Center for Health Statistics.
Survey data are representative of the U.S. civilian noninstitutionalized population.
Perchlorate is measured in urine samples obtained from individual survey participants.
About the Perchlorate Indicators
Perchlorate is a naturally occurring and man-made chemical that is used to make fireworks, explosives, flares, and rocket fuel. It is found naturally in groundwater and soils throughout many arid regions; and has been detected in surface water and some foods, including dairy products and infant formula. Perchlorate has also been detected in bodily fluids like human breast milk, urine, blood, amniotic fluid, and saliva.
Exposure to high doses of perchlorate blocks the uptake of iodide into the thyroid gland which impacts thyroid hormone production. This is of particular concern for women of child-bearing age, because thyroid hormone impacts the growth and development of babies’ brains. Insufficient thyroid hormone levels during early pregnancy have been linked to reduced childhood IQ scores and other neurodevelopmental effects. EPA has determined that exposure to perchlorate may cause adverse effects on human health, including reduced IQ in children following prenatal exposures. EPA has committed to issue a drinking water regulation for perchlorate by May 2027.
For historic and contextual information about perchlorate and these indicators, see the Perchlorate section of America's Children and the Environment, Third Edition (pdf) .
Data Sources and Methods - Perchlorate
The National Center for Health Statistics, a division of the Centers for Disease Control and Prevention, conducts the National Health and Nutrition Examination Surveys (NHANES), a series of U.S. national surveys of the health and nutrition status of the non-institutionalized civilian population. Interviews and physical examinations are conducted with approximately 10,000 people in each two-year survey cycle. The survey measures perchlorate levels in urine samples collected from NHANES participants. These indicators focus on children and women of child-bearing age because of concern for potential adverse effects in children born to women who have been exposed to perchlorate.
- Detailed Methods for Indicator B12 and B13 (pdf)
- Metadata for National Health and Nutrition Examination Surveys (NHANES)
Related Links
- U.S. EPA: Perchlorate in Drinking Water
- U.S. EPA: Technical Support Document: Deriving a Maximum Contaminant Level Goal for Perchlorate in Drinking Water
- Agency for Toxic Substances and Disease Registry (ATSDR): Public Health Statement for Perchlorates
- Centers for Disease Control and Prevention (CDC): National Report on Human Exposure to Environmental Chemicals
- National Academy of Sciences (NAS): Health Implications of Perchlorate Ingestion
- U.S. Food and Drug Administration (FDA): Perchlorate Questions and Answers