The Centers for Disease Control and Prevention (CDC) has released the first
National Report on Human Exposure to Environmental Chemicals, an important new
research tool that will provide better information on levels of exposure to
environmental chemicals, and over time what these levels mean for public health.
Advances in a technology known as biomonitoring allow CDC to measure chemicals
directly in blood and urine samples rather than estimating population exposures by
measuring air, water, or soil samples. Based on this scientific advancement, the new
report provides data on actual levels of chemicals in humans. As data are collected
over the years, researchers will be better able to determine possible health effects
and design appropriate public health strategies.
"This new resource is a significant development in the field of environmental
health," said Health and Human Services Secretary Tommy G. Thompson. "It
will help us to better track the exposures of Americans to chemicals in the
environment and to measure the effectiveness of our public health efforts."
This first report initially measures the exposure of the U.S. population to 27
environmental chemicals. The report includes metals (e.g., lead and mercury),
pesticide metabolites, phthalate metabolites and cotinine (which tracks exposure to
tobacco smoke). Levels of environmental chemicals were measured in blood and urine
samples collected from participants in CDC's National Health and Nutrition Examination
Survey (NHANES) - an ongoing national health survey of the U.S. population. The Report
provides results from the 1999 survey; data from future years will help confirm these
"The Report is a major step toward assessing in the U.S. population which
environmental chemicals are present in blood and urine samples, who is exposed, trends
in exposure over time, and whether interventions to reduce exposure are working,"
said Richard J. Jackson, MD, MPH, Director of CDC's National Center for Environmental
Although the report does not include new information on health risks of exposures
or on potential routes of exposures, this is the first time that national exposure
levels of the U.S. population are known for 24 of these 27 chemicals. CDC previously
assessed the population's exposure to three substances -- lead, cadmium, and cotinine,
and the report provides new data for the 1999 calendar year. Previously, only limited
data were available on which environmental chemicals were in the U.S. population and
at what levels.
The presence of a chemical in blood or urine does not necessarily indicate that the
chemical will cause disease. Additional research is required to determine whether the
levels reported are a cause for health concern.
The first Report provides information on the exposure of the U.S. population to
these 27 substances. The chemicals, grouped into four categories, are as follows:
: lead, mercury, cadmium, cobalt, antimony, barium, beryllium, cesium,
molybdenum, platinum, thallium, tungsten, and uranium.
Tobacco smoke: cotinine - a metabolite of nicotine that tracks tobacco smoke
Organophosphate pesticides (Six metabolite measurements representing exposure to
28 pesticides): dimethylphosphate, dimethylthiophosphate,
dimethyldithiophosphate, diethylphosphate, diethylthiophosphate, and
diethyldithiophosphate. These metabolites are generally formed by the breakdown of 28
pesticides, including chlorpyrifos, diazinon, fenthion, malathion, parathion,
disulfoton, phosmet, phorate, temephos, and methyl parathion.
Phthalate metabolites: mono-ethyl phthalate, mono-butyl phthalate,
mono-2-ethylhexyl phthalate, mono-cyclohexyl phthalate, mono-n-octyl phthalate,
mono-isononyl phthalate, and mono-benzyl phthalate.
Highlights of the Report
Cotinine is a breakdown product of nicotine after it enters the body. Levels of
cotinine in the body track the amount of exposure a person has to tobacco smoke. For a
nonsmoker, cotinine tracks exposure to environmental tobacco smoke. CDC measured
cotinine in nonsmokers in the U.S. population as part of a previous survey, and the
Report presents new cotinine data for 1999.
"One significant finding was the more than 75% decrease in serum cotinine
levels for nonsmokers in the United States," said Jim Pirkle MD, PhD, of CDC's
Environmental Laboratory and co-author of the report. "This decrease documents a
dramatic reduction in exposure of the U.S. population to environmental tobacco smoke
since 1991. However, environmental tobacco smoke remains a major public health concern
since more than half of American youth continue to be exposed to this known human
CDC has been measuring the population's exposure to lead since 1976 through the
NHANES surveys. CDC's Childhood Lead Poisoning Prevention Program (www.cdc.gov/nceh/lead/lead.htm)
works to reduce exposure of children in the United States to lead. The Report
presents blood lead level measurements for U.S. children in 1999.
"The good news is that blood lead levels continue to decline among children
overall," said Eric Sampson, PhD, of CDC's Environmental Laboratory and also a
co-author of the report. "However, other data show that children living in
environments placing them at high risk for lead exposure remain a major public health
Environmental health is one of the Leading Health Indicators in Healthy People
2010. Information on environmental chemical exposures will assist clinicians and
public health officials to better understand the relationship between toxic exposures
and health consequences and guide public health prevention efforts. CDC will add other
substances to future reports based on data obtained from samples collected in
subsequent NHANES surveys. CDC will continue to measure the 27 original substances as
well. The goal over the next few years is to expand the Report to provide information
about 100 chemicals. CDC will monitor trends over time that may help scientists better
understand the impact of the environmental chemicals on our health. In the future, CDC
will be able to report exposure levels for more specific population groups (e.g.,
children, minority populations, or women of childbearing age).
In addition, CDC will expand the Report to include exposure data from studies of
people exposed from localized or point-source exposures (e.g., data on levels of
mercury in people who eat mercury-contaminated fish from a polluted river). For more
information on the Report data, log onto www.cdc.gov/nceh/dls/report
or call 1-866-670-6052.