HAZARDS OF NANOMATERIALS

Preview This section describes hazards associated with nanoparticles and nanomaterials. 

Nanotechnology is the idea that we can create devices and machines all the way down to the nanometer scale, which is a billionth of a meter, about half the width of a human DMA molecule. 

INCIDENT 4.3.3.1 NICKEL SENSITIZATION WORKING WITH NANOPARTICLES  

What lessons can be learned from this incident  

Nanotechnology is a relatively new and exciting field. It is producing significant and important materials and technologies that have the potential to make dramatic improvements in our lifestyles and will continue to impact the way we do chemistry in the future. However, the rapid evolution of manufacture of nanomaterials has produced a new class of materials some of whose health hazards are not clearly understood and many have not been evaluated. This section briefly describes nanomaterials and discusses the known and speculated hazards associated with these materials and processes, and the implications and precautions for working with these materials in the laboratory. 

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Stephen R. Clough, The Potential Ecological Hazard of Nanomaterials, in Nanotechnology AND THE Environment, 15-16 (Kathleen Sellers et al. eds., 2009). 

In the last few decades one notices strong influence and fast expansion of applications of various nanomaterials for industry, medicine, and many other areas that affect the everyday life. Unfortunately, current advantages of such materials can be accompanied by their unexpected and dangerous effects in the near future. These effects can include various types of toxicity together with hazardous ecological impacts. Obviously, possible hazardous aspects of nanomaterials require studies that would reveal their characteristics and provide guidelines to facilitate their safe applications. Predictive models for nanomaterials can be useful for both theoretical and practical reasons. 

With the development of nanomaterials concerns exist about their toxicity and health impacts. Because of the size of nanoparticulates, concerns arise about then-ability to penetrate tissue and cause harmful effects ranging from mild irritation to more serious tumor developments. In the case of nanoclays, one has to consider that nanoclays only become nanosized after incorporation and exfoUation in a polymer matrix. In a practical sense, the presence of crystalline silica, a material that may be found in clays, is probably more of a real hazard. Crystalline silica is regulated to extremely low levels in commercial day materials [112] (see also Chapter 19). 

Knowledge of hazards for nanomaterials is limited. Current studies will produce more short-term, repeated, and longterm exposure information. Since nanomaterials have not been around very long, long-term study results will take a while. 

Moreover, considering the impacts of dermal exposures and corresponding hazard concerns of nanomaterials, it must be taken into consideration that the dermal uptake of nanoparticles will be an order of magnitude smaller than the uptake via the inhalation or oral routes of exposure (Warheit et al., 2007b). However, damaged skin or sites with sldn flexing may be areas of increased risk for the penetration of nanoparticles (Levin and... 

Tb assess the risks associated with chemical substances such as nanomaterials, it is necessary to first identify and characterize possible hazards and estimate the likelihood and magnitude of exposure. The potential health risks of nanomaterials win be determined by their hazard potential, including dose-response relationships and exposure levels. This will require an understanding of the physicochemical properties of the nanomaterial and the conduct of appropriate and weU-designed in vitro and in vivo studies to characterize the toxicological effects and associated dose-response for the nanomaterial (Figure 1.2). 

Toxicokinetic data following various routes of exposure, so that information about absorption, distribution, metabolism, and excretion can be identified, and doses for hazard assessment determined. This includes dose-response data for the target organs, and knowledge of the subcellular location of nanomaterials and their mechanistic effects at the cellular level ... 

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