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Janet Gray, Ph.D.
Janet Gray, Ph.D.

As author of our 2008 and 2010 State of the Evidence reports, Dr. Gray drives the science behind all our work.

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Low-Dose Exposures

In the past two decades, evidence has accumulated to suggest that minute exposures to some chemicals can lead to profound health impacts. Whereas prior assumptions suggested that high doses could be toxic while low doses would be safe, and that the relationship between dose and safety was a straight line, newer evidence suggests that some chemicals can exert serious effects at low doses and may behave differently at different doses. Instead of straight lines that show the relationships between doses and effects, some may be wavy or even U-shaped.

While prevailing wisdom indicates that we’re exposed to multiple chemicals at any given moment, most studies of chemicals’ effects explore one chemical at a time. Finally, exposures to chemicals and radiation occur in the context of an individual’s genes, life history, social stresses, and health behaviors.

  • Low Dose Effects

    Some chemicals negatively affect health at very low doses.

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  • Interactions

    Exposures to chemicals and radiation interact with other personal and social factors.

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  • Mixtures

    In real-life, we're exposed to mixtures of exposures, and the health effects from these mixtures can multiply.

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  • Non-monotonic Curves

    The relationship between the dose of a chemical and health effects can be complex.

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