Data Discussion

The Indicator Defined

This indicator might be loosely defined as the presence of toxic, man-made chemicals residing in the average person’s body. Because this is a new area of concern, which chemicals should be followed and at what levels has not been defined. For the time being, focus is on some of the most commonly used toxic chemicals at any detectable amount.

Data Interpretation/Evaluation

In 2005, the Toxic-Free Legacy Coalition tested 10 Washington residents for the presence of toxic chemicals in their bodies. The participants submitted hair, blood and urine samples to testing for six groups of chemicals: the plasticizing chemicals known as phthalates; PBDEs (flame retardants); heavy metals such as lead, arsenic, and mercury; perfluorinated chemicals like those used to make Teflon; pesticides; and banned, but persistent, PCBs and DDT.

The study found that all of the participants had most of these toxic chemicals in their bodies in varying amounts. Only Carbaryl, DMP, and DMTP chemicals were not present at detectable levels. This finding is consistent with similar studies conducted in other states such as Oregon and California.

Because the participants in these State-wide studies are not representative of the overall population, it is not possible to make meaningful comparisons between the levels detected in one group versus another. All we can safely conclude is that most of the tested compounds appear to be present in most people.

The Centers for Disease Control and Prevention (CDC) released a report (also in 2005) measuring 148 chemicals in blood or urine samples collected from approximately 2400 people who participated in CDC's National Health and Nutrition Examination Survey (NHANES) from 1999 -2002.

They found a significant decline in exposure to second hand smoke and continued decrease in children’s blood lead levels. However, the report also acknowledges that there is no established “save” level of exposure for most of the chemicals in the study and that more research was needed to understand the effects of the chemicals on human health.

A common argument against concerns about chemical exposures is that the presence of minute amounts of chemicals in our bodies is not necessarily harmful. However, there are many instances of chemicals having negative health impacts at lower levels than had previously been understood (blood levels of lead in children, for example). In addition, there is growing evidence that the timing of exposure can be as important as the dose. For example, some studies have shown a single dose of certain pesticides on a critical day of development can cause permanent changes in brain chemistry and hyperactivity in lab animals.

Only one quarter of the 82,000 chemicals in use in the U.S. have ever been tested for toxicity. In addition, we don’t yet understand the cumulative effects of constant re-exposure to these chemicals. For example, most of the compounds dissipate within weeks or days under normal conditions. However, “normal” does not include the constant re-exposure most of us experience. Nor do we know or these compounds interact with each other in our system and what that might mean in terms of our health.

For an excellent (and sobering) exploration of toxic chemicals and their effects on humans around the globe, check out the Humane Toxome Project which is working to define the full scope of industrial pollution in humanity: http://www.ewg.org/sites/humantoxome/

 

Data Source and Limitations

There is very little data available on this topic. It is only recently that anyone has started to measure average levels of exposure among large numbers of Americans. This is due to the expense of the testing, a lack of regulation requiring it, and technological limitations. Tests for individuals normally cost around $15,000 and only a few labs have the ability to detect the small trace amounts involved.

The data and data discussion for this indicator was drawn from the following sources:

http://www.cdc.gov/exposurereport/

http://www.cdc.gov/exposurereport/pdf/thirdreport_summary.pdf

http://www.pollutioninpeople.org/

http://www.toxicfreelegacy.org/index.html

http://www.oeconline.org/

http://www.bodyburden.org/

http://science.nationalgeographic.com/science/article/toxic-people.html

http://seattlepi.nwsource.com/health/233680_condor25.html

http://lifelessplastic.blogspot.com

http://www.ewg.org/sites/humantoxome/

 http://blog.wired.com/wiredscience/2008/11/common-lab-gear.html

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