Medical Monitoring & Biomonitoring

Biomonitoring is the measurement of environmental chemicals and/or their metabolites in biological media such as blood or urine and is an important tool for assessing exposure to both naturally occurring and synthetic chemicals. One of the largest current biomonitoring efforts in the United States is the National Biomonitoring Program. Undertaken by the U.S. Centers for Disease Control and Prevention (CDC) in 2001, the National Biomonitoring Program releases regular updates to The National Report on Human Exposure to Environmental Chemicals. The most recent edition includes biomonitoring data on 212 environmental chemicals, 75 of which are measured and reported for the first time. Another large biomonitoring effort of the CDC is the National Health and Nutrition Examination Survey (NHANES) report, which includes not only biomonitoring data, but also health demographics and statistics for participants from across the country.

Biomonitoring measurements give an indication of potential chemical exposures to different populations of people. They can also inform us about trends in exposures over time. The use and application of biomonitoring data to make public health policy, although not new, is of increasing importance to regulatory decision-making. However, these data are constrained by the detection limit of the analytical methods used. Further, certain biomarkers of exposure (for example, metabolite levels) may not be specific for any one chemical. Most importantly, biomonitoring data do not address whether the measured exposures are associated with any inherent toxicological risks.

Medical monitoring is a surveillance effort to observe a population of people over time for the possible development of certain diseases or health conditions. Medical monitoring may be requested in response to known chemical exposures. Although appealing in some circumstances, medical monitoring may not always be practical or desired. Reliable and effective medical tests or treatment may not be available for the diseases/conditions to be monitored. Alternatively, the available tests may not be sufficiently sensitive or specific to provide reliable results, which can lead to unwarranted health concerns.

Exponent toxicologists, epidemiologists, industrial hygienists, and physicians are experienced in assisting clients in matters surrounding requests for biomonitoring data or medical monitoring. We have expertise in the science and policy for a wide range of environmental chemicals including lead, arsenic, mercury, pesticides, PCBs and plasticizers. We have designed and conducted biomonitoring studies of exposed communities and have addressed issues surrounding the potential for increased health risks due to exposure. Exponent is especially experienced in advising on how best to structure compelling presentations on issues of exposure, causation, test reliability and effectiveness, and other related scientific and medical matters. Proper evaluation of causation and risks of disease from exposure to chemicals is complicated and poses challenges in effective communication to different audiences. Exponent’s scientists have published extensively on these topics; have discussed scientific issues on biomonitoring and medical monitoring at scientific meetings and technical workshops; and have been appointed to Federal and State expert panels related to biomonitoring issues.

Example Publications

Nichols BR, Hentz KL, Aylward L, Hays SM, Lamb JC. 2007. Age-specific Reference Ranges for Polychlorinated Biphenyls (PCB) Based on the NHANES 2001-2002 Survey. Journal of Toxicology and Environmental Health, Part A. 70:1873-1877.

Tsuji JS, Garry MR, Perez V, Chang ET. 2015. Low-level Arsenic Exposure and Developmental Neurotoxicity in Children: A Systematic Review and Risk Assessment. Toxicology 337:91-107.

Tsuji JS, Van Kerkhove MD, Kaetzel RS, Scrafford CG, Mink PJ, Barraj LM, Crecelius EA, Goodman M. 2005. Evaluation of Exposure to Arsenic in Residential Soil. Environmental Health Perspectives 113:1735-1740.

Tsuji JS, Williams PRD, Edwards MR, Allamneni KP, Kelsh MA, Paustenbach DJ, Sheehan PJ. 2003. Evaluation of Mercury in Urine as an Indiciate of Exposure to Low Levels of Mercury Vapor. Environmental Health Perspectives 111:623-630.

Professionals

Knowledge