Assessing the Risk of Nanoparticles

The focus of current scientific and regulatory activities is on engineered or synthetically produced substances with nanoscale dimensions. There are numerous naturally occurring nanoscale components of substances such as mineral deposits and volcanic dust, and in byproducts of common processes such as diesel exhaust and byproducts of coal combustion. Although exposure to these nanomaterials may be minimal and controlled in most cases, studies on such common nanomaterials as fog, coal dust, and ultrafine aerosols have provided useful information as to exposure and effects of particles this small, and these results are useful in predicting the properties of engineered nanoparticles. 

Conventional studies of inhalation toxicity generally use toxic doses measured in terms of mass per unit volume. Some studies have shown that this unit of measurement may not be appropriate for nanoparticles. For example, in one study of 100 nm particles of titanium dioxide evoked the same amount of pulmonary inflammation as a ten-times greater mass of larger (1-2.5 pm) particles [9]. The smaller-sized greater surface area versions of substances may afford exceptional benefits. For example, silver has been used successfully as a bactericide, but now it has been found that nanoscale silver has greatly enhanced effectiveness [10]. 

Ongoing research into the properties of nanoparticles is necessary to confirm that their beneficial effects are not outweighed by hazards/ risks. This research is proceeding in numerous laboratories and has a very high priority in commercial and government programs. The research encompasses general issues as well as those related to specific substances. Such research will go on for decades as new nanomaterials, and their applications, are discovered. 

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