EMERGING CONCERNS - Marine Pollution: What Everyone Needs to Know - page 129

transistors, lasers, lubricants, medical implants, water purifiers,
sunscreens and cosmetics, and food additives. Nanoparticles are
microscopic particles that are larger than individual molecules,
and have at least one dimension less than one hundred nano-
meters (a nanometer is one billionth of a meter or one millionth
of a millimeter). Nanomaterials or nanoparticles (NPs) (<100
nm) can be made of different materials; some come from com-
bustion like diesel soot, and some are manufactured. Because of
their size, they have unusual properties that make them useful
for drug delivery, gene therapy, and other biomedical uses, as
well as in the optical, cosmetics, materials science, and electron-
ics fields. They may be made of carbon (nanotubes, fullerenes),
transition metals (gold, platinum, silver), metal oxides (titanium
dioxide, zinc oxide), plastic (polystyrene), or silica, and are being
manufactured in increasing amounts. Fullerenes, named after
Buckminster Fuller (the designer of geodesic domes), are hollow
spherical molecules composed of 60 atoms of carbon. Informally
called buckyballs, they resemble soccer balls.
One reason for concern about nanomaterials is that since
they are so small, they may interact with the environment and
living things in unexpected ways. They are extremely diverse,
exhibiting a wide variety of properties. Particular classes are of
concern because of their potential impacts on human and envi-
ronmental health, including nanosilver, carbon nanotubes, and
fullerenes. NPs pose possible dangers because they are reactive
and can pass easily through cell membranes. They can cause
inflammation in the lungs, and because of their tiny size they
are highly mobile and able to move from their original site (the
lungs from being inhaled) to other parts of the body. Inside
cells, NPs can stimulate the formation of reactive oxygen species
(ROS) that interfere with DNA, proteins, and cell membranes.
Greater use of NPs has led to their release into the envi-
ronment in runoff and sewage effluent, and their accumula-
tion in coastal environments. They have come under scrutiny
as potential pollutants. For example, the nanoparticle form of
titanium dioxide after exposure to ultraviolet radiation can be