POTWs: Big Trouble with Nanowaste
Publicly owned treatment works
(POTWs) use an amazing arsenal
of equipment to prevent large
troublemakers, such as animal carcasses
and tree limbs, from entering their
wastewater treatment processes. However,
they don't yet have the necessary
technology to keep out nanoparticles,
which some worry could have a much
worse impact on the quality of the water
these plants treat.
Just as it is hard to understand how
big the potential problems with nanotechnology
could be, it’s also difficult to
fully comprehend how small “nano”
really is. Defined as one billionth of a
meter, a nanometer is one-hundredthousandth
the width of a human hair.
Much of the concern is based on how
compounds change when they are nano
size. For example, at the nano level,
some compounds shift from inert to
active, from electrical insulators to conductors,
from fragile to tough. They can
become stronger, lighter, or more
resilient. These transformed properties
are what account for the infinite variety
of applications of nanoparticles, which
are defined as anything less than about
100 nanometers in diameter.
The concern is that nanomaterials
could affect water and air quality in
areas where these compounds are dispersed.
At this time, very little is known
about nanotoxicology, which might be
quite different from the toxicology of the
same materials at normal scale. For
example, Vicki Colvin, a chemist at Rice
University, said recently that the usual
way to assess toxicity, by measuring a
toxin’s mass, won’t work at the nano
level. Nanomaterials have a much higher
surface-to-mass ratio, and while this
makes them good for such purposes as
water filtering, it just as well could cause
them to interact with human body cells
that their extremely small size allows
them to infiltrate.
A newly released report, "Where Does
the Nano Go? End-of-Life Regulation of
Nanotechnologies," focuses on how little
information there is on the environmental
fate and effects of nanomaterialcontaining
wastes. The report was written
by environmental law experts Linda
Breggin and John Pendergrass of the
Environmental Law Institute and was
commissioned by the Project on Emerging
Nanotechnologies, an initiative of
the Woodrow Wilson International Center
for Scholars and The Pew Charitable
Trusts.
.
“POTWs are on the front lines, and
they’re not getting enough information,”
said Pendergrass on July 26 at a
briefing when the report was officially
released.
Liquid waste disposed of in waters
treated by POTWs is exempt from regulation
under the Resource Conservation
and Recovery Act (RCRA), according to
Pendergrass. The rationale is that regulations
issued under the Clean Water
Act would address those wastes.
Pendergrass commented that some
private manufacturers of nanotechnology
products, especially small start-up
companies, may be pouring some liquid
wastes containing nanomaterials into
the public sewage system without the
knowledge of the impacted POTWs.
The U.S. Environmental Protection
Agency has already begun taking action
related to the manufacture of nanotechnology.
In November 2006, the agency
stated it would regulate nanoscale silver
used in washing machines to kill bacteria.
EPA’s action was prompted by POTW
managers and operators who worried
the nanosilver could be released into
wastewater by washing machines that
contain this nanomaterial.
Under RCRA regulations, a waste generator
is required to share with the firm
that treats its waste any information it
has that will help the waste handler
manage it safely, Pendergrass said.
In contrast to actions mandated
under RCRA, according to Pendergrass,
a company or research institute that is
releasing liquid waste with nanomaterials
in it is not required to provide
POTWs with information to ensure they
are working safely with those wastes.
Just as the debate about the possible
dark side of nanotechnology has rapidly
heated up, so has the commercial success
of this new technology. More than
$30 billion in products incorporating
nanotechnology were sold globally in
2005. By 2014, Lux Research estimates
this figure will grow to $2.6 trillion.
Nowadays, with hundreds of nanotechnology
products already on the
market, one of the questions in greatest
need of attention is how various forms
of nanomaterials will be disposed of and
treated at the end of their use. They may
end up in our POTWs, landfills, or incinerators,
and, consequently, in our water,
soil, or air. Responding to such growing
concerns about nanotechnology, EPA
has launched its Nanoscale Materials
Stewardship Program.
We still have much to learn about the
potential risks to human health and the
environment posed by nanotechnology
and its byproducts. So important is this
issue that the ultimate success or failure
of this exciting new technology may
possibly depend on how fully these
issues are addressed. Only when these
concerns are resolved can our society in
good conscience promote the development
of nanotechnology in an environmentally
sustainable manner.
This article originally appeared in the 10/01/2007 issue of Environmental Protection.