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Questions and Answers: Biomonitoring and Environmental Monitoring


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Cancer and Health Effects

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What is biomonitoring?

Biomonitoring is the direct measurement of a chemical in human tissue or fluids.

What kinds of samples can be examined during biomonitoring?

Whole blood, serum, lymphocytes, white blood cells, urine, saliva, fat tissue (adipose tissue), breast milk, toenails, hair, and even exhaled breath.

Is biomonitoring a new concept?

The United States had a biomonitoring program from 1967 to 1990 called the National Human Monitoring Program. It was run by the Centers for Disease Control (CDC) and included monitoring organochlorine chemicals in human fat samples. This program, called the National Human Adipose Tissue Survey, was phased out in 1990. Since 1990, the CDC has conducted limited biomonitoring, mostly connected with Super Fund chemicals. The CDC has followed trends in levels lead, solvents and pesticides in blood. The modern biomonitoring movement and new programs started in the mid 1990s. Dr. Lynn Goldman, then an administrator with the Environmental Protection Agency (EPS), recommended a public health approach to monitoring environmental chemicals in 1995. By 1998, the Pew Environmental Health Commission was established at Johns Hopkins University. In their report the Pew Commission recommended a coordinated environmental public health tracking system that would establish a national biomonitoring program that would be linked to systems tracking human diseases. The CDC was given the mandate to develop the biomonitoring program, and develop the infrastructure for a public health tracking program. Other initiatives are underway at other agencies. (For more information, see Links to Other Resources.)

What is environmental monitoring?

Environmental monitoring is the periodic or continued measurements of chemicals in samples such as soil, water, and air. Technical advances similar to those in biomonitoring have taken place in this field, making it possible to track contaminants in smaller samples and at smaller concentrations.

Is water testing related to environmental monitoring?

Water testing or monitoring is one type of environmental monitoring. Environmental monitoring and biomonitoring are linked because both are ways to measure exposure to chemicals. Biomonitoring tests human tissues to discover what is inside the human body. Environmental monitoring is a way to test for outside or external exposures to chemicals. The samples that are tested in environmental monitoring include water, food, and soil. Some of the same advances that are making biomonitoring easier and less expensive are having the same effect on water monitoring and other types of environmental monitoring. If biomonitoring shows an exposure in humans, environmental monitoring to determine where and how the exposure occurred can be an important additional step.

How does biomonitoring fit with cancer risk factor research?

Identification of a cancer risk factor often follows a three-stage process. The stages are not necessarily completed in order. The first stage is identifying a potential health hazard. The middle stage is monitoring exposure (biomonitoring and/or environmental monitoring), and the final stage is surveillance to determine health effects. At this point, the middle stage has advanced so rapidly that it may take years for the first and final stages to "catch up." The reports being released by the CDC show what levels of which chemicals are in human tissues. This data can show that an exposure is lower than average, baseline, or higher than average. It can't, and doesn't, however, provide information about health impacts linked to those chemicals and levels.

What health effects are being studied through biomonitoring?

Because modern biomonitoring with small samples and better detection of low level exposures is new, most of the focus is on gathering basic exposure data. Once there is more information about the numbers, types, and concentrations of chemicals in samples, hypothesis about specific health effects of chemicals can be developed and tested.

Is biomonitoring being used in cancer risk factor studies?

The Sister Study is exploring environmental interactions relating to breast cancer. They are specifically targeting occupational chemicals and chemicals encountered in everyday life. For more information, see The Sister Study.

The Agricultural Health Study (AHS) is doing extensive biomonitoring on farmers and farm families. This study incorporates both biomonitoring on human tissue samples and environmental monitoring in the working and home environment of the participants. This study is making the connections between external exposure and internal levels. For more information, see The Agricultural Health Study.

The Breast Cancer and the Environment Research Centers (BCERC) are incorporating biomonitoring into their research into exposure to environmental agents that may affect breast cancer risk. For more information, see The Breast Cancer and the Environment Research Centers.

What are some limitations of biomonitoring?

In some ways biomonitoring is a finite process. It can uncover exposures and detail how much of which chemicals are found in human tissue samples. However, the interpretation of those results, the connections to possible health effects, and understanding of what exposure levels cause what health effect have to come from further study. The CDC is collecting enormous amounts of information from biomonitoring but only after that information is studied and analyzed will we have answers to questions about health effects.

What programs or agencies are involved in biomonitoring?

Biomonitoring is being pursued by both federal and state agencies. Some, like the CDC, are forming links with other groups to create larger information networks. Some of the programs currently in place are run by:

What chemicals are being studied?

The CDC's Third National Report on Human Exposure to Environmental Chemicals (published in early 2005) tracked 148 chemicals. (For the complete list of chemicals, see List of Chemicals in the CDC's Third National Report PDF.) Some categories of chemicals being monitored include metals, organochlorine pesticides, pyrethroid pesticides, and phthalates. (The CDC's first report (2001) included 27 chemicals and the second (2003) included 116.)

How might biomonitoring data impact public health?

Biomonitoring may eventually provide data necessary to prove hypothesis about cause and effect links between hazards and health effects.

In addition, Dr. Bill Suk and colleagues from the National Institute of Environmental Health Sciences predicted biomonitoring may lead to: "…the identification of potentially hazardous exposures before the adverse health effects appear and to establish exposure limits minimizing likelihood of significant health risks." (Suk W., Human biomonitoring: research goals and needs, Environ Health Perspect, 104 (Suppl 3):479-483, 1996)

Although it often takes many years for an adverse health effect to appear after an exposure (this can be particularly true for cancer), it's possible that biomonitoring may provide us with the information necessary to identify biomarkers for DNA exposure, for DNA damage, or for the disease itself.

Last Update 10.19.05