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California Environmental Health Tracking Program

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Last Edited: 8/11/2010


Biomonitoring is an important part of Environmental Public Health Tracking.  CEHTP is initiating two pilot biomonitoring projects.  More details will be available on this website as the studies become established.  To learn more about biomonitoring, scroll down or select from the topics below.

What is biomonitoring?

Biomonitoring is the measurement of contaminants such as pesticides and other chemicals in the body.  It is accomplished by analyzing samples from the body such as urine, blood, breast milk, saliva, or hair.

Biomonitoring is one of the three main pillars of Environmental Public Health Tracking: hazard tracking, exposure tracking (biomonitoring), and health outcome tracking. Biomonitoring is important as it can give the public, scientists, and other stakeholders information about actual exposures – measures of which contaminants are entering the human body – as opposed to just information about contaminants which are present in the general environment (hazard tracking).

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What can be measured through biomonitoring?

Contaminants themselves can be measured in samples of urine, blood, breast milk, saliva, hair, or other human tissues. Often scientists measure the metabolites of contaminants, which are substances produced from chemical reactions with the contaminants in the body, instead of the actual contaminant.

Biomarkers are substances which can indicate that an individual as been exposed to a contaminant (either a direct measurement of the contaminant or its metabolite in blood, for example). These types of biomarkers are called biomarkers of exposure. Other biomarkers are measurable changes in the body’s function, which are indicative of a potential or established disease. These biomarkers are called biomarkers of effect. Examples of biomarkers of effect include changes or alterations in DNA or changes in blood cholinesterase activity after exposure to pesticides.

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Processes and challenges for biomonitoring

A biomonitoring project typically entails involvement of a community in study planning, questionnaire assessment, and biological sampling (collection of human tissues). Often, environmental sampling such as measurement of contaminants in air or soil can happen concurrently with biological sampling. Human samples need to be stored properly before laboratory analysis. The contaminant needs to be present in the environment at high enough levels to be able to be detected in human tissues. Laboratory methods need to be developed or made available for each compound to be measured. Results of biomonitoring need to be communicated back to participants in meaningful ways. If there are no statewide or national averages of contaminant levels to compare an individual result to, it is difficult to know if an exposure is high or low. If an exposure is deemed to be high, it is often difficult to know what actions an individual should take beyond reducing one’s exposure (unless the level reflects an acute exposure in which medical attention is warranted immediately).

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CEHTP biomonitoring projects

The California Environmental Health Tracking Program (CEHTP) aims to build capacity in California to track biomonitoring data along with hazard and health data. The CEHTP is interested in examining exposure to contaminants in communities which have the potential to be highly exposed. The CEHTP is also committed to returning results of biomonitoring back to participants in a meaningful and culturally sensitive way.

The CEHTP is currently initiating two biomonitoring studies.  One study is focused on agricultural pesticide exposure in the Central Valley.  The other study is focused on perchlorate exposure in Imperial County.  Both studies involve partnerships with local community-based organizations.  Pease revisit this site as the details of these studies and other studies emerge.

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Biomonitoring resources

Below are some of many resources for biomonitoring.  We will continue to add to this resource list.

  • The California Biomonitoring Program is the first state level biomonitoring program. The Program will determine baseline levels of environmental contaminants in a representative sample of Californians, establish time trends in chemical levels, and assess the effectiveness of current regulatory programs.
  • The Commonweal Biomonitoring Resource Center (CBRC) provides information and expertise to community-based groups and non-governmental organizations interested in many aspects of biomonitoring using human biospecimens. The Center helps communities design and implement biomonitoring studies, and provides information about previous studies, and links groups who have already conducted studies or who have used biomonitoring data for community campaigns to those interested in following a similar path.
  • Biomonitoring is not presently conducted widely in California. The CDC conducts biomonitoring on a national scale and reports results in their National Report on Human Exposure to Environmental Chemicals. Data are not available on a statewide basis; only as a national snapshot.
  • The European Commission is working in collaboration with member states to develop a unified European Human Biomonitoring Program.
  • The Human Toxome Project of the Environmental Working Group seeks to identify and characterize the human body burden of many industrial chemicals.
  • Biomonitoring is a key part of environmental public health tracking.  Read about biomonitoring and EPHT at the national tracking website.
  • Cornell University fact sheet on biomonitoring.

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