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Welcome to PSR's Environmental Health Policy Institute, where we ask questions -- then we ask the experts to answer them. Join us as physicians, health professionals, and environmental health experts share their ideas, inspiration, and analysis about toxic chemicals and environmental health policy.


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The Future of Exposure Science: New Opportunities from New Tools

Posted on May 17, 2012

By Gina M. Solomon, MD, MPH

This essay is in response to the question: Which Way Forward for Toxics Advocacy?

Society is on the cusp of major advances in exposure science. These advances will generate large amounts of new information, democratize the collection and availability of that information, and drive improvements in chemical toxicity testing and regulatory policy. This essay describes what’s coming, and what it will mean for public health and the environment.

In the field of biomonitoring, newer analytical instruments will allow the screening of samples such as blood or urine for tens of thousands of chemicals. Instead of taking a single sample and testing it for a specific chemical, or even for 200 specific chemicals, this approach essentially allows researchers to ask: What is in this person’s blood and urine? The new biomonitoring techniques are already starting to be deployed in small studies. When these studies scale up to involve hundreds or thousands of people, they will become revolutionary, especially since they will be partnered with informatic approaches that allow researchers to answer questions such as:

  • Which chemicals are most widespread in the population?
  • Which chemicals occur at higher concentrations in sensitive populations, such as young children or pregnant women?
  • Which chemicals exhibit the largest variability in concentration across populations of interest or across geographic areas?
  • Which chemicals are increasing over time?
  • Which groups of chemicals tend to co-occur?

Historically, we have seen the power of biomonitoring to drive science, public concern, and policy. For example, a decade ago, scientists in Sweden laboriously identified an unknown organohalogen in Swedish breast milk samples as pentabromodiphenyl ether. That finding rocketed the PBDE flame retardants into the center of scientific and public attention. There was an immediate demand for toxicity data, for more biomonitoring data, for identification of sources and exposure pathways, and for action - including widespread bans on these chemicals. The PBDEs also created a more generalized public awareness about toxic flame retardant chemicals, and sensitized the public to the “Whac-a-Mole” problem, where one chemical of concern is phased out only to be replaced by others that either have their own significant hazards, or are untested.

Fundamentally, people don’t like to discover potentially hazardous chemicals in their bodies, so biomonitoring has generated dramatic public attention, public concern, and pressure for action. There are still deficiencies in the regulatory response, but at least there is more attention to these problem chemicals, and some regulatory and consumer action has occurred.

My prediction is that the advances in biomonitoring will result in an exponential increase in the discovery of potential chemical hazards in humans. These discoveries will prompt the urgent need for toxicity testing information, as well as for information about the cumulative toxicity of commonly co-occurring mixtures, what products these chemicals are used in, and how humans are exposed. In turn, this information will tend to drive more health-protective regulations. The worst position for a company then will be to be blind-sided by the discovery of one if its chemicals in people – especially in vulnerable subgroups such as children – and not be forthcoming with full and adequate data on toxicity, use, and sources of exposure.

The advances in exposure science, however, don’t just involve biomonitoring. Microsensor and nanosensor technologies, the development of new direct-reading instruments, Smartphone-connected technologies, and advances in portability, availability, and simplicity of lab and field instruments will dramatically democratize the collection of data on emissions and environmental concentrations of substances of concern. NGOs are poised to take advantage of these technological advances. For many years, the Bucket Brigades have provided simplified air sample collectors to community groups, which have deployed these collectors at the fence lines of refineries and chemical plants. Nearly a decade ago, researchers at NRDC used portable instruments to take simultaneous measurements inside and outside diesel school buses. Our finding – that the concentration of diesel particulate matter was about four times higher inside the bus than in a car driving ahead of the bus – spurred action to retrofit and replace old school buses. Just a few years ago, we deployed a portable mercury vapor detection instrument, and discovered higher levels of mercury downwind of cement kilns, compared to upwind. This information helped to spur action to regulate mercury emissions from the cement industry. These kinds of studies will become much easier and cheaper in the near future.

New developments in the portability and availability of monitoring technologies also mean that it will be increasingly possible for community groups and small NGOs to conduct exposure studies. The instruments can be operated by someone without specialized training. At the same time, companies that are developing these technologies are eager to lease – or even lend – their instruments to researchers or NGOs for use in short-term studies, with the expectation that publication of the results will encourage broader adoption. This means that chemical companies will increasingly need to consider the possibility that community groups, sometimes in partnership with academic researchers, will be monitoring at their fence lines and making the results publicly available almost instantly via the Internet. Because these monitoring devices are so portable, it will not take long for NGOs to deploy them globally, including in developing countries where regulatory oversight is less stringent. High levels of dangerous chemical emissions from facilities in China or India owned by major multinationals may not get much regulatory attention in those countries, but this information could get significant public attention in the polluter’s home country.

Advances in exposure science, including both biomonitoring and environmental monitoring, will give scientists and communities new tools they can use to gather information about which chemicals may be contaminants of concern. This exposure information will ultimately force the generation of more and better scientific information on chemical toxicity and risk, and will also allow communities to hold polluters accountable for their local and global actions.


Art Unger, M.D. said ..

50 years ago a pamphlet by the "Medical Letter" listed all known drug interactions; when I retired, the list was many times as long. I bet toxics interact. Is a lead level that is safe for most people, not safe for those with even a little mercury in their bodies? Are some Persistent Organic Pollutants especially dangerous for those with certain genes, diseases or treatments? I knew of two papers that found 2 to 4 alcoholic drinks a day protected against Coronary Artery Disease. Does that much alcohol effect hepatic detoxification?

May 23, 2012

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