Click here to see our Video News Release summarizing the implications of biomonitoring.
Dr. Whelan speaks about biomonitoring on WCBS TV in New York.
In the simplest terms, biomonitoring is the sampling and measurement of specific chemicals in biological tissue. The concentration of a chemical in human tissues or the total amount of a chemical in the body is sometimes referred to as the “body burden” of an individual. Due to the constant relationship we have with our environment, we are exposed to thousands of natural and man-made chemicals every day. This exposure occurs from air, food, and water, as well many consumer products with which we come into contact on a daily basis. In addition to tens of thousands of chemicals that naturally occur in foods, there are also natural sources of chemical exposure, including minerals leaching into ground water from soils, dioxins from forest fires or volcanic eruptions, and biological processes (as with pollen, hormones, and hydrogen sulfide). Of course, virtually everyone is also exposed to many man-made chemicals, such as those in paints, cosmetics, pesticides, drugs, plastics, household cleaners, carpeting and fuels. Each of us has ingested, inhaled, or absorbed most of these chemicals, many of which are easily measured in blood or urine.
Biomonitoring data can indicate the amount of a substance actually absorbed into the body. Because of technological advancements, it is now possible to detect extraordinarily low concentrations of chemicals in human tissue. Data from both toxicology (the study of the chemicals, generally done on animals) and epidemiology (the study of distribution of human disease) suggest that the vast majority of chemicals currently detected in biomonitoring programs of the general population would not produce adverse health effects.
Data from biomonitoring are becoming more widely available and are often considered newsworthy. However, these data are often presented without proper context, which can lead people to the mistaken conclusion that the low levels of chemicals found in our tissues are generally harmful, simply because a chemical is present. But merely detecting a chemical does not equal hazard or risk. For example, when physicians detect triglycerides in blood at a concentration of 75, that information by itself is not helpful to the layperson. But if the physician tells the patient that scientific information indicates that concentrations less than 150 are considered “ideal,” then the information has some meaning. This is the same challenge that faces those who collect biomonitoring data and then attempt to tell the public how much of a particular chemical in a sample should be of concern.
Many factors need to be considered before it is possible to determine if the detected levels of a chemical might pose a human health hazard. Reporting data without context can frequently generate confusion and unnecessary anxiety. It is not very useful to say, for example, “Mary has 20 parts per trillion (ppt) of benzene in her blood.” For most of the over 200 chemicals that are now being monitored by the Centers for Disease Control and Prevention (CDC) and others, interpreting results is difficult. Fortunately, there is a good possibility that in the near future, scientists will be able to present biomonitoring data in a way that will be informative and perhaps helpful in improving public health. To use the example of Mary again, it is likely that within a few years we will be able to say “Mary has 20 ppt of benzene in her blood. This places her at about the 50th percentile of benzene levels for adults in the United States. It is believed that about 80% of the benzene in her body has come from miscellaneous exposure to chemicals in the environment and the remainder is due to her own natural biological processes. The concentration measured in Mary is about 10% of the average level seen in petroleum workers – who have been shown not to have an elevated occurrence of benzene-related disease.” This kind of risk communication could well be beneficial to society.
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