[6] Historically, public health regulations have been based on theoretical risk calculations according to known levels of chemical substances in air, water, soil, food, other consumer products and other sources of potential exposure.
[citation needed] Human biomonitoring offers the opportunity to analyze the actual internal levels of bodily substances from all potential routes of exposure at one time, which may contribute to improving risk assessments.
[8][better source needed] A single biomonitoring measurement is only one snapshot in time and may not accurately reflect the level of exposure over longer periods.
[12] Because this approach requires establishment of cause and effect in epidemiological studies and a thorough understanding of human dose response, data to support these types of action levels exist for only a few environmental chemicals.
[14] Chemicals and their metabolites can be detected in a variety of biological substances such as blood, urine, exhaled air, hair, nails, feces, semen, breast milk, or saliva.
[14] Breast milk is a favored matrix (substance) to measure lipophilic (fat-loving) persistent, bioaccumulative, and toxic (PBT) compounds during lactation; this exposure route is dominant for breastfeeding children.
[14] Scientists performing biomonitoring testing are able to detect and measure concentrations of natural and manmade chemicals in human blood and urine samples at parts-per-billion to parts-per-quadrillion levels.
A 2006 U.S. National Research Council report found that while scientists were capable of detecting the chemicals at these levels, methods for interpreting and communicating what their presence meant regarding potential health risks to an individual or population were still lacking.
[18] The report recommended that scientific research be done to improve the interpretation and communication of biomonitoring results through the use of existing risk assessments of specific chemicals.
[20] Subsequently, an expert panel from government, industry and academia, convened to develop detailed guidelines for deriving and communicating these Biomonitoring Equivalents.
[20] Since 2007, scientists have derived and published Biomonitoring Equivalents for more than 110 chemicals, including cadmium, benzene, chloroform, arsenic, toluene, methylene chloride, triclosan, dioxins, volatile organic compounds, and others.
[30] The issue of exposure to environmental chemicals has received attention as a result of televised reports by Bill Moyers for PBS and Anderson Cooper for CNN's "Planet in Peril" series.
[44] A major use of occupational toxicology data is for determining what biomarkers (including both the a toxicant and its metabolites) may be used for biomonitoring, and establishing biological exposure indices.
These biomarkers are intended to aid in prevention by identifying early adverse affects, unlike diagnostics for clinical medicine that are designed to reveal advanced pathologic states.
[48][49] In the United States, the Occupational Safety and Health Administration as of 2017 has three regulations that require biomonitoring: after exposure to benzene in an unplanned release, and for employees exposed to cadmium or lead at or above a specified level over a specified amount of time.
[44] Voluntary lists of biological exposure limits or action levels are maintained by the American Conference of Governmental Industrial Hygienists, German Research Foundation, UK Health and Safety Executive, France's ANSES, and the Swiss Accident Insurance Fund.