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Division of Laboratory Sciences

The Biomonitoring Program of the National Center for Environmental Health, Centers for Disease Control and Prevention

What is Biomonitoring?

Biomonitoring is the measurement of environmental chemicals in the human body, specifically in blood, urine, serum, saliva, or tissues. The results of biomonitoring are used to help make decisions for protecting people from illness, birth defects, disabilities, cancer, or death due to environmental chemicals. For example, if you think that you have come into contact with an environmental chemical, biomonitoring can help answer the following important questions:

• Did an environmental chemical get into your body?

• What environmental chemical has gotten into your body?

• How much of an environmental chemical has gotten into your body?

• Is the amount of an environmental chemical that got into your body enough to hurt your health?
  
  Public health officials use the answers to these questions to do the following:
  

• Identify people who need medical treatment.

• Identify the right medical treatment.

• Prevent people from coming into contact with substances that can hurt their health.

• Evaluate how well prevention activities are working.

  Biomonitoring enables better decision making for protecting health.

CDC's Biomonitoring Program

The Environmental Health Laboratory of the National Center for Environmental Health, Centers for Disease Control and Prevention (CDC) conducts CDC's Biomonitoring Program. The program includes the following activities:

Biomonitoring. The lab is capable of measuring 200 environmental chemicals (or their breakdown products) in human blood, urine, or serum. It can measure lead, mercury, arsenic, uranium, cadmium, benzene, many pesticides, many endocrine disruptors, polychlorinated biphenyls (PCBs), vinyl chloride, and many other substances that are known to be dangerous to health. No other lab in the world can measure exposure in people as quickly and reliably, and some of the exposure measurements are done nowhere else in the world.

Portable Blood Lead Analyzer

More efficient · Less costly · Easy to use

Technology and test development
The lab develops instruments and tests for biomonitoring that improve the diagnosis, treatment, and prevention of disease due to exposure to environmental chemicals.  For example, the lab supported development of the first portable blood lead analyzer. It is being used to screen children, wherever they may be located, for harmful exposure to lead.  This tool increases the chances of identifying children whose health is at risk from lead and of referring them for prompt medical care when needed. 

Quality assurance and standardization. CDC's lab helps other labs around the world standardize and improve their programs for measuring specific substances in people that affect their health. These activities result in more reliable test results. For example, through its Blood Lead Laboratory Reference System, the CDC lab helps other labs improve the overall quality of their measurements of lead in blood.

The lab uses its biomonitoring tests and technologies to help 1) protect public health during emergencies involving chemicals, 2) investigate possible exposure of people to dangerous chemicals, and 3) study the effects of chemicals on health.

Benefits of Biomonitoring

Identifies who is in danger. Some people are at greater risk of coming into contact with environmental chemicals than others. Researchers can use biomonitoring to find out which groups of people are in the most danger from environmental chemicals and take steps to protect them.

Improves actions to protect health. Environmental chemicals can be measured in people before and after taking actions to protect health. Comparing the levels of the substances before and after preventive actions can show whether the actions have helped improve or protect health and to what extent. Without this information, public health officials will have a more difficult time knowing whether or not their programs are actually helping people.

Improves decision making. Just because an environmental chemical is in the environment doesn't mean that it is getting into people or making them sick. Biomonitoring provides a measure of people's actual exposure to environmental chemicals. Officials can use this data to find out whether a substance is causing a health problem, to determine how to treat the problem, and to plan how to prevent exposure in the future.

Improves emergency response. Sometimes there is an outbreak of what seems to be the same illness among many people, and the cause of the illness is unknown. Biomonitoring can be used to test people to find out exactly what is making them sick, how to treat them medically, and how to prevent future exposure.

Recent Biomonitoring Results

Dieldrin. Researchers at CDC and in Denmark found that the risk for breast cancer significantly increased with increasing levels of dieldrin, a pesticide, in women's blood. This finding suggests that exposure to organochlorine compounds, such as dieldrin, may increase the risk for breast cancer.

Methyl parathion. Methyl parathion is a dangerous pesticide that should never be used indoors. Over the past 2 years, it has been sprayed illegally inside thousands of homes in at least seven states and has resulted in the death of two children in Mississippi. In response to this emergency, the lab developed a method to measure methyl parathion in urine and measured methyl parathion in more than 15,000 people. The results helped identify who needed medical treatment and who needed to be moved out of their homes until the homes could be cleaned.

Trihalomethanes. Trihalomethanes are chemicals that evaporate easily into the air and are thought to be linked to birth defects, bladder cancer, and colorectal cancer. These chemicals are often found in drinking water because they are formed during the water - sanitation process. In 1998, the lab developed a method to measure trihalomethanes in blood. This method is being used in studies to find out how much of these chemicals is getting into people's bodies and whether the chemicals are causing illness.

Click image to enlarge.
These lab results indicate that secondhand smoke is getting into the bodies of nonsmokers.

Cotinine. Cotinine is a chemical formed by the breakdown of cigarette nicotine in the body. The lab developed methods to measure cotinine in saliva, blood, and urine. These methods are being used to find out 1) how much secondhand smoke is getting into children, adolescents, and adults; 2) what levels of chemicals in tobacco smoke cause health problems; 3) how well actions to protect people from secondhand smoke are working; and 4) how well actions to help current smokers stop smoking are working.

Partnerships and Collaborations

The lab continues to share its pioneering work in biomonitoring to measure human exposure to environmental chemicals with federal, state, and local agencies. Federal partners include the Agency for Toxic Substances and Disease Registry, the U.S. Environmental Protection Agency, the Food and Drug Administration, and the National Institutes of Health.

NHANES. In collaboration with CDC's National Center for Health Statistics, the lab has served as the central laboratory for the National Health and Nutrition Examination Survey (NHANES) since 1971. The surveys provide information on the prevalence of exposure to environmental chemicals and disease and risk factors for disease (including genetic risk factors) in the U.S. population. NHANES data are used to develop sound health policies, to direct and design health programs and services, and to evaluate whether these policies, programs, and services are helping to improve the nation's health. In 1998, the lab developed analytical methods and completed the pilot phase for the next survey. Work on the survey began in March 1999.

Click image to enlarge.  
The lab has measured blood lead levels in U.S. children for more than 20 years. These graphs indicate that efforts to prevent the lead poisoning of children are working and need to continue.

What's New?

National Report on Human Exposure to Environmental Chemicals. The first report, issued in 2001, provides information about the exposure of the U.S. population to 27 environmental chemicals. By comparing the results over time, public health experts will be able to see how health is being positively or negatively affected as levels of exposure to environmental chemicals change. The lab will report the data according to the age, sex, race or ethnicity, geographic area, and income level of the people tested to see whose health is at risk. The Report will be used to identify exposures to environmental chemicals that can affect human health, to identify whose health is most at risk, and to monitor how well actions to prevent exposure are working. The lab's goal is to expand the Report to cover a total of 100 priority environmental chemicals. 

Other Environmental Health and Laboratory Activities

Besides biomonitoring-related activities, CDC's lab conducts activities that help ensure better diagnosis, treatment, and prevention of selected chronic diseases.

Quality assurance and standardization. In addition to ensuring the quality of blood lead measurements, CDC's lab provides quality assurance, standards, references, and technical assistance through the following programs: 1) the CDC Lipid Standardization Program for assisting labs in measuring lipids and cholesterol, which are factors in cardiovascular and other diseases; 2) the Newborn Screening Quality Assurance Program for assisting labs in conducting tests to detect treatable, inherited metabolic disorders such as sickle cell disease; 3) the HIV Quality Assurance Program for assisting labs in detecting antibodies for HIV in dried-blood-spot specimens; and 4) the Diabetes Reference Laboratory Program for improving the diagnosis, treatment, and prevention of diabetes.

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