Nanomaterials health hazards

Presently, quantitative health hazard and exposure data are not available for most nanomaterials. Therefore, health risk evaluation for the workplace currently relies to a great degree on professional judgments for hazard identification, potential exposures and the application of appropriate safety measures. 

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. 

Health Hazards and Recycling and Life Cycle Assessment of Nanomaterials and Their Composites... 

Yuan G (2004) Natural and modified nanomaterials as sorbents of environmental contaminants. J Environ Sci Health, Part A Toxic/Hazardous Subst Environ Eng 39 2661-2670... 

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). 

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). 

In addition to obtaining information to perform a hazard and dose-response evaluation, an exposure assessment will need to be conducted to estimate and characterize any potential risks associated with nanomaterials. If the hazard identification process reveals that a nanomaterial is iimocuous and does not pose a potential for eliciting any adverse human health or environmental effects, it may not be necessary to conduct additional toxicological studies or an extensive exposure assessment. In cases where the hazard evaluation determines a potential for adverse effects for the nano-material, in vitro and/or in vivo studies may be conducted to evaluate the potential for systemic exposure from inhalation, oral, or dermal penetration. Such information may help to refine the exposure assessment by providing estimates of internal doses. Much of the published human toxicological and epidemiology data relate to airborne exposme to nanoparticles or ultrafine particles. However, there are additional routes by which humans can be exposed to nanomaterials that may need to be considered, including ... 

There are several challenges associated with the evaluation of the potential human and environmental health risks from the development and use of novel nanomaterials, including the selection of appropriate toxicological studies for conducting hazard evaluations, a need for instruments that can measure nanomaterials in various media (air, soil, and water), information about nanomaterial levels in products, and the need for increased funding for EHS research. 

A profile of the nanomaterial s inherent hazards, which identifies and characterizes the material s potential environmental, health, and safety hazards ... 

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