Biomonitoring, the measurement of environmental chemicals and/or their metabolites in human tissues and body fluid, is an important tool in assessing environmental exposures to naturally occurring and synthetic chemicals. The use and application of biomonitoring in making public health policy, although not new, is of increasing importance to regulatory decision making. For more than 30 years, the Centers for Disease Control and Prevention (CDC) have collected biomonitoring data in conjunction with the National Health and Nutrition Examination Survey to evaluate both population and national exposure trends, and to determine whether public health interventions have been successful in reducing exposures to environmental toxicants, such as lead and secondary smoke.
Since 2001, the CDC has issued the biannual National Reports on Human Exposure to Environmental Chemicals. The Fourth National Report, parts of which are scheduled for release during 2007 and into 2008, is expected to provide biomonitoring data on more than 200 diverse chemical substances. Technology and analytical methods have progressed to the extent that a wide variety of chemicals and their metabolites (e.g., metals, pesticides, plasticizers, polychlorinated biphenyls, and dioxins) are detectable, even in minute quantities, across the U.S. population. The CDC has emphasized in the National Reports that the mere detection of a chemical substance in urine or blood should not be interpreted as indicating the presence of a health risk or potential disease in individuals or the U.S. population (CDC 2005). However, media attention and non-government organization (NGO) reports have raised concern about chemical body burdens and such concern will likely impact chemical and pesticide regulatory policy and future litigation.
Regulators and policy makers, challenged to determine how best to apply biomonitoring exposure data in quantitative risk assessment, are funding research to better comprehend both the applications and interpretations of these data. After an extensive evaluation of the state of the science, the National Academy of Sciences (NAS) National Research Council Committee on Human Biomonitoring for Environmental Toxicants, in the July 2006 report, “Human Biomonitoring for Environmental Chemicals,” provided recommendations to improve study design, data interpretation, and risk communications (NAS 2006). In doing so, NAS concluded that:
The ability to generate new biomonitoring data often exceeds the ability to evaluate whether and how a chemical measured in a population may cause a health risk or to evaluate its sources and pathways for exposure.
The use of biomonitoring will continue to grow, because of the strong motivation and need to more accurately assess risk and potential liability from environmental exposures. Most importantly, whether disease currently exists or does not exist, biomonitoring can serve as an indicator of whether interventions are needed to reduce exposures (either for an individual or a population), and thus to improve public health and prevent the onset of future disease.
Exponent’s toxicologists are widely recognized in the scientific and regulatory communities in the application of biomonitoring to human health and environmental risk assessment problems. Our expertise includes the science and policy for lead, arsenic, mercury, pesticides, plasticizers (BPA, phthalates), dioxins, PCBs, and a broad- array of industrial chemicals, including perfluorinated hydrocarbons. We are recognized experts in the field and have designed and conducted biomonitoring studies of exposed communities and to address whether farm families, applicators, wives an their children, have more risk from pesticides than other families who do not live or work on farms. We been also been appointed to Federal and State expert panels, published extensively and discussed scientific issues on biomonitoring at scientific meetings and technical workshops.
Biomonitoring is not a stand-alone means of evaluating health risk in individuals and populations. Scientifically sound risk assessment requires the integration of all the available data, animal and medical toxicology studies, human epidemiology, pharmacokinetic modeling and the evaluation of environmental factors to determine how a chemical substance may have entered the body and whether the absorbed dose can exert an adverse toxic effect. The selection and interpretation of biomarkers, as an indication of metabolites to confirm exposure, may also require reassessment and validation if EPA and OSHA moves forward to revise regulatory exposure limits for human and environmental risk based standards.
Exponent’s staff with specialties in more than 90 technical disciplines that includes toxicology, epidemiology, medicine, industrial hygiene, pharmacokinetics, exposures dose reconstruction and environmental science can provide highly qualified individuals to both the design and execution biomonitoring studies including the choice of biomarkers of exposure. We can also provide scientifically sound guidance how new and of existing data may be used by regulators evaluating whether legal limits of exposure have been exceeded and whether resulting exposures provide a health risk to the public, consumers, farm families and workers in manufacturing and agriculture.