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probably become widely used for toxicity testing. Although the new technology-
driven approaches to in vitro toxicity testing and high-throughput screening con-
stitute an important advance in hazard evaluation of new chemicals, they are not
yet ready to replace traditional approaches to hazard evaluation because of in-
herent limitations of extrapolation from in vitro to in vivo findings, as discussed
above. But they will be very useful in setting priorities among new chemicals for
more thorough toxicity testing. Additionally, the new technologies will greatly
augment traditional approaches to in vivo toxicity evaluation by providing
mechanistic insights and more detailed characterizations of biologic responses at
doses well below those shown to produce toxicity. That will be especially im-
portant in evaluating endocrine-active chemicals and chemically induced altera-
tions that may occur during early life.
McHale et al. (2010) have discussed the importance of new -omics tech-
nologies and of a systems-thinking approach to human health risk assessment of
chemical exposures, or systems toxicology. EPA has already begun to examine
such approaches to predictive in vitro toxicity assessment through the ToxCast
program (EPA 2008a). It is evident that new approaches to data management
and analysis will be critical for the success of computational approaches to pre-
dictive toxicology. The statistical and modeling challenges are immense in ad-
dressing the large volumes of data that will come from systems-toxicology ex-
periments, which are an essential element of EPA's computational-toxicology
effort. It will be critical for the success of this and other efforts that involve large
amounts of data for EPA to have access to the best available tools and technolo-
gies in informatics.
Example of Using Emerging Science to Address Regulatory Issues and
Support Decision-Making: Predicting the Hazards of a New Material
Nanotechnology is an emerging technology that poses new challenges for
EPA. Deemed the next industrial revolution, nanotechnology is predicted to
advance technology in nearly every economic sector and be a major contributor
to the nation's economy. The rationale of that prediction is that nanoparticles,
with dimensions of 1-100 nm, have properties that are useful in a wide variety of
applications, including electronic, photovoltaic, structural, catalytic, diagnostic,
and therapeutic.
A potential concern is that some of the properties of nanoparticles might
pose risks to human health or the environment. The challenge for EPA is to use
or develop the science and tools needed to assess and manage the widespread
use of nanoscale materials that have unknown hazards. That includes assessing
potential risks associated with an emerging technology and, if necessary, moni-
toring potential exposures and hazards. Using nanotechnology as an example,
the committee identified several questions that can be used to better understand
the risks associated with new science and tools. Many of these issues regarding
the environmental, health, and safety aspects of nanotechnology are addressed in
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