Page 26 - Environmental Nanotechnology Applications and Impacts of Nanomaterials

12 Nanotechnology as a Tool for Sustainability

about interactions between fullerenes and microbial populations. This
is a critical knowledge gap not only because of the potential to impact
microorganisms themselves, but also because these organisms serve as
the basis of the food chain and as primary agents for global biogeo-
chemical cycles. Ecotoxicological aspects of nanomaterials are discussed
in Chapter 12.
The matter of determining whether a substance is “dangerous”
involves not only determining the material’s toxicity or hazard, but also
its exposure or probability of coming in contact with an organism. When
materials are persistent and resist degradation, they may remain in the
environment for long periods of time, contributing to increased chances
of exposure. Persistent materials have a greater chance of interacting
with the living environment. The roles of particle deposition and aggre-
gation in determining nanomaterials’ persistence in the environment are
discussed in Chapter 7. The extent to which nanomaterials may be
degraded and the conditions that may lead to their breakdown, includ-
ing metabolism and degradation by bacteria, remain virtually unknown.
While it is possible that bacteria may accelerate the dissolution of min-
eral nanoparticles through, for example, their impact on redox condi-
tions, little work has been done examining the interactions between
bacteria and these materials. Early efforts exploring biodegradation of
the carbon-based fullerenes revealed that, at best, these materials will
be difficult to degrade and therefore should be scrutinized for their per-
sistence in the environment.
Chapter 13 addresses the framework for assessing the risks of nano-
materials, and why such a framework may diverge from the methods of
assessing conventional materials. There is some temptation to use the
information known about bulk materials of similar composition to describe
nanomaterials in assessing risk. For instance, the material safety data
sheet (MSDS) for carbon black has been applied for C since they both
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consist of only carbon atoms. Using such data for the bulk-phase format
of a material may be a useful exercise as a first step if the results are inter-
preted with the appropriate degree of skepticism. However, the novel
properties of these materials must be incorporated into risk models if, as
we suspect, they are found to change their interactions and effects.
While much more study will be needed to assess the true risks to
health and the environment posed by nanomaterials, there is an imme-
diate and urgent need for information assessing the risks of producing
these materials.
Indeed, many of the materials used to make nanomaterials are cur-
rently known to present a risk to human health in their own right. In one
recent study [26], the procedures for making nanomaterials were assessed
using methods employed by the insurance industry to quantify risk and
estimate premiums for chemical manufacturers. An encouraging trend we