The Regulation of Occupational Exposure to Nanomaterials: A Proposal
The Regulation of Occupational Exposure to Nanomaterials: A Proposal
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纳米材料职业接触监管：一项提案
DOI：
10.1080/19338241003697110
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发表时间：
2010
影响因子：
1.8
通讯作者：
T. Guidotti
中科院分区：
文献类型：
--
作者：
T. Guidotti
Nanomaterials represent a major challenge in occupational health protection.1 Uncertainty over the best way forward is causing delay in regulation despite rapidly growing use of nanomaterials by industry and widespread distribution in consumer products. By the time a satisfactory approach to risk assessment, standards setting, and risk management is agreed upon, “nano” could well be a mature technology.2 Nanomaterials are artificial objects on a scale of 100 nm (10−7 m) or below, smaller than most bacteria and in the size range of viruses and larger molecules.1,3 There are many nanomaterials that are of significance in environmental health, the mostly familiar perhaps being fine particulate air pollution and the more exotic products of combustion known as fullerenes (the 60and 80-carbon structures named after inventor Buckminster Fuller). Engineered nanoparticles are fabricated objects on this scale that are designed for a purpose. Their commercial applications have grown from low-tech, as an ingredient in sunscreen, to highly sophisticated. Engineered nanomaterials are now used or in the final stages of development for biomedical research, medication delivery systems, oilfield stimulation, cosmetics, composite materials, antiseptics, smart textiles, advanced metal alloys, catalysts, filters, and photovoltaic devices, and this is just the beginning. They come in many different configurations: spherical structures, tubes or wires, sheets, cages trapping metal ions, crystals, and branching structures. Next on the horizon are nanoscale machines, with engineered parts. Many of the applications of nanomaterials are fundamental to “green” and energy-conserving technology, so slowing down development would not be a viable option even if it were possible. However, nanomaterials have properties that raise concerns for environmental and occupational health. Like fine particulate air pollution, their potential for toxicity is disproportionate to their mass, because material so finely divided has an enormous surface area relative to its weight, Particles this small stay airborne for a very long time, and disperse rapidly and widely at a relatively homogeneous concentration compared to familiar particulate pollution or contamination. Nanoparticles in open air will spread quickly throughout a workplace environment, will be readily inhaled, will penetrate deeply into the respiratory tract, and will have the potential to cause unpredictable problems. Although they are small solid particles, it is most useful to think of nanoparticles as a different state of matter, from the point of view of regulatory policy. This is because they are so small that the familiar properties of their composite materials in bulk become irrelevant and new properties govern their behavior, including quantum effects that have no counterpart on a macroscale. (For example, on a nanoscale, gold is not shiny and yellow: it is red.) It seems fairly clear, because of the enormous range of sizes and variations in configuration that are possible with nanomaterials, not to mention engineered activity such as electrical properties (some nanoparticles have semiconductor properties) and mechanical action, that nanomaterials cannot be regulated as a single class. There must be individual attention, with each nanomaterial treated as a new product. But is it possible to make at least some generalizations so that nanomaterials can at least be regulated in groups rather than one at a time, seemingly presenting a regulatory nightmare? The risk presented by some nanoparticles may resemble that of fine and ultrafine particulate air pollution, which show an exposure-response relationship but no toxicity threshold, have the capacity to migrate in the body to reach target organs other than the lung, and exert their effects even in nonsusceptible population subgroups. There may also be similar issues involving immune responses, oxidant load, intracellular overload, and inflammation. There are no clear studies so far that characterize the risks of nanoparticles under reasonable operating conditions. One human study of an egregious exposure situation, although confounded by exposure to other contaminants,4 and several animal studies suggest that health risk may be driven by respiratory, cardiovascular, and neurodegenerative outcomes. There is always the risk of cancer to be concerned about,
