Nanoparticles are ubiquitous and can be either naturally occurring or manufactured, but researchers are just starting to study them closely, and safety questions remain unanswered. Properties vary greatly from material to material and even within the same element: some carbon nanotubes do not affect human health, for example, while others, like those found in diesel exhaust, may act like asbestos fibers in the lungs.
Nanotechnology deals with materials at the level of 1 to 100 nanometers, with a nanometer (nm) being a billionth of a meter; the ratio of a meter to a nanometer is the same as that of the Earth to a marble. The smallest things visible to the naked human eye are 10,000 nanometers.
Anytime the “nano” label is applied to a product or technology, it’s worth getting clear about what it means. In one sense, nanotechnology is all around us: everything is made out of molecules, which can be measured in nanometers. What makes nanotechnology different from normal manufacturing is elements such as use of electron microscopy during R&D and use of tiny nanoparticles to make products and materials.
An example is textiles, on which a coating of nanoparticles may be applied to offer stain repellence, mold resistance, and other properties. These coatings are commonly made of substances that are toxic and polluting in their bulk form, like fluorochemicals and silver. While less of the chemical is used, reducing the amount added to the environment, this is possible because nanoparticles are often very potent—so nanoparticles of some substances may be more toxic than their bulk counterparts. Research suggests that this is because of their size, which allows them to easily penetrate and damage cells.
Most scientific research into the safety of nanomaterials has used scenarios that hint at concerns but don’t represent real-world scenarios. For example, a study in which placentas were injected with polystyrene nanoparticles demonstrated that such particles could potentially pass through a placenta from mother to baby, but the study only begins to provide clues to how real-world exposures might play out. While nanoparticles used as a manufacturing feedstock seem unlikely to become inhalable or ingestible in everyday exposure, studies of questions like this are few and far between.
In the absence of better information,
EBN has tended to evaluate nanotech products based on the likelihood of occupants, workers, or the environment being exposed to nanoparticles during the life cycle of the product. In textiles, where nanosilver may be loosely attached to the surface of a fabric, that appears likely.
Better data is needed, though, and this may take more regulation. A 2005 report by Lux Research even suggested that nanotech companies avoid researching possible risks in order to avoid liability. Let’s hope that researchers get more serious—and more funded—and get past such a see-no-evil approach.