Types of Human Biomonitoring Techniques

Environmental pollution is on the rise. Human biomonitoring, a technique for assessing exposure to harmful environmental chemicals, provides an answer. The technique is used to help control and prevent population exposures to pollutants, and a number of methods exist. Most important to the integrity of the research is considering age, health and geographical location, factors that affect individual body levels, and remembering that while biomonitoring can quantify exposure, it cannot determine the source of exposure or how long the agent has been inside the body.

Commonly Sampled Substances

• Researchers look for markers left by the environmental agent, which can be the agent itself, a product of the agent or a change in the individual resulting from either of these. Tissue and fluid samples from an individual are analyzed; both chemicals and their metabolites are measured. The most common substances sampled are urine, expelled air, blood and breast milk; fat, bone, nails, hair and other tissues are also sampled. Typically, the substance to be measured is determined by whether the agent is more likely to be absorbed by fat or water.

Single Cell Gel Electrophoresis (SCGE) Assay

• This method, also referred to as the comet assay, is highly effective because researchers can collect data at the level of the individual cell. This is particularly advantageous with regard to genotoxicological studies. The statistical analysis is more robust than that of other methods, fewer cells are required per procedure and more types of cells can be used. Combined with bacterial enzymes, the comet assay can determine the oxidative DNA damage that leads to certain health conditions, and using fluorescence techniques has pinpointed sites of damage along the DNA sequence.

Electrothermal Atomic Absorption Spectrometry (ETAAS)

• Also called graphite furnace atomic absorption spectrometry, this method vaporizes samples in a furnace coated with graphite. If the elements being tested for are present, the resulting cloud of atoms will absorb light at wavelengths characteristic of those elements.

Inductively Coupled Plasma Mass Spectrometry (ICP-MS)

• This method, developed in the late 1980s, analyzes the charge ratios of samples (solid or liquid) that are decomposed to neutral elements in a high temperature matrix. Mass fragments are sent into a vacuum chamber where they are measured for various elements down to part per trillion levels or even, for some elements, part per quadrillion levels.

Benefits of Human Biomonitoring

• Results obtained from studies using human biomonitoring techniques can benefit society as a whole. The reduction of lead in gasoline imposed by the U.S. Environmental Protection Agency is one example. Assays also helped determine exposure to secondhand smoke, and correlated adverse neurodevelopmental effects to the presence of methylmercury in blood and hair. Analysis can establish trends in entire populations (e.g., Americans) and subgroups (e.g., age, sex, ethnicity).