Health effects of nano-dusts

SEM image of CNTs. © Materialscientist, Wikimedia Commons
SEM image of CNTs. © Materialscientist, Wikimedia Commons

Many applications of nanotechnologies have only existed for a few decades. However, data on ultrafine dust exposure have been available for a long time and, in particular, epidemiological studies can provide information on the effects of nano-dusts. More information can be found on the IFA website State of discussion of the effects upon health. The contact person of the IFA is Christian Schumacher (Fachbereich 3 Gefahrstoffe: Umgang - Schutzmaßnahmen,   email).

Results of toxicological studies

Schulte et al. (2008) designate a series of parameters that influence the possible toxicity of nanoparticles.

Roller (2008) suggests the dust volume in combination with the particle diameter should be a dosimeter scale in the context of the development of lung tumors in animal experiments. Unfortunately, only in a few toxicological studies were the used dusts completely characterized in terms of the above-mentioned parameters.

In addition, animal experiments are difficult to carry out since suspension medium effects are of greater importance when dealing with such small particles.

As part of the OECD, the "Working party on Manufactured Nanomaterials" examines the appropriateness and applicability of test methods for chemicals on nanomaterials.

Carbon nanotubes (CNT)

In the recent past, the discussion has become more acute as to what extent an asbestos-like effect can be caused by carbon nanotubes (CNT). CNTs are biocompatible and have the dimensions of the definition of WHO fibers (length > 5 μm, diameter < 3 μm and length-to-diameter ratio > 3:1) (IFA asbestos at workplaces).

Poland et al. (2008) investigated the effect of CNT, which had partially been produced for this purpose, in the abdominal cavity of mice. Takagi et al. (2008) investigated similar effects using a particularly sensitive mouse strain. Both studies give rise to the concern that ultrafine fibers, which are sufficiently long and bio-persistent, may produce cancer. The studies used carbon nanotubes which resemble asbestos fibers in shape and length. In addition, the results of Shvedova et al. (2008) point out that carbon nanotubes, which do not conform to the WHO fiber definition, but which are present in agglomerated form, may have a harmful effect on health.

Current assessment of nanoparticles

The European Commission clarifies how nanomaterials under REACH have to be treated and will review this process constantly. The effects on human health and the environment over the entire life cycle of the CNT are studied within the initiated and funded research activities of the federal government (e.g. Network NanoCarbon).

Despite the prevailing uncertainty about the effects of nanoparticles, Schulte et al. (2008) conclude that there is sufficient preliminary information to treat nanoparticles "as if" they were hazardous substances. The NanoKommission of the German Federal Government comes to a similar conclusion. Thus, the Working Group 3 of the NanoKommission phrased in its "Principles for responsible use of nanomaterials" under the principle 4 "establish risk management”:

"Until scientifically-based knowledge is available, a possible hazard potential for a given nanomaterial cannot be ruled out. In these cases, the precautionary principle (according to the EU Communication of February 2000) has to be applied."