11/30/2007

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.

Further info


AplusA-online.de - Source: Environmental Protection