Article first published online: 9 DEC 2011
DOI: 10.1002/etc.733
Copyright © 2011 SETAC
Issue
Environmental Toxicology and Chemistry
Special Issue: Nanomaterials in the Environment
Visualize printing all 24 volumes of the Encyclopaedia Britannica on the head of a pin. In 1959, Richard Feynman articulated this reality in an insightful address at the annual meeting of the American Physical Society. In what became a prophetic speech, “There's plenty of room at the bottom” 1, Feynman discussed manipulating and controlling matter on a small scale. Back then, forward thinking conjured images of going to the moon in an era when computers occupied entire floors of buildings. Fifty years later, we no longer have to imagine. We are actively manipulating and controlling materials and devices on the scale of nanometers.
With these advances, researchers have heralded both positive and negative effects of nanotechnology. Advocates point to efficient energy consumption, a cleaner environment, and eradicating health problems. Others have noted we do not know enough about how nanomaterials function, how they add potential stressors to the environment, or what chemical reactions may result when nanomaterials meet other particles. Both groups have called for further debate and advanced research into nanotechnology to determine the balance between risks and benefits.
The ability to build products inexpensively with almost every atom in the right place holds tremendous promise for advances in virtually every sector of society. For example, smart drugs will deliver medicine only to the cells that need it; strong yet light materials will be used for automobile bumpers, airplanes, and tennis racquets; and tiny reactive particles will clean water at a fraction of previous costs. Although these benefits are exciting to scientists, they are often mysterious to the general public. One unknown involves the safety of these emerging materials, often called engineered nanomaterials. Scientists characterizing the environmental, health, and safety of nanomaterials (Nano EHS) are obligated to produce reliable data on which quantitative risk assessments can be built. In the past two decades, scientists have advanced this area, learned from mistakes, and realized that tools developed for working with substances dissolved in a solution cannot a priori be applied to particles. Although life on earth evolved in the presence of natural nanomaterials (including carbon, cellulose, and nanosilver), engineered nanomaterials—those produced for a specific purpose—may be identical to natural nanomaterials, but pose potential hazards due to significantly elevated environmental concentrations. In many instances, the question may be how engineered nanomaterials differ from natural nanomaterials. It is precisely this difference that may define their potential for adverse effects.
Against this background, this article seeks to answer several questions: Where does the science need to provide reliable data that will assist policymakers and regulators develop strategies to manage nanomaterials and instill public confidence regarding the safety of these materials? What are the critical needs that will move us forward safely and intelligently in this promising field? Are the paradigms generally developed to assess the fate and effects of solute contaminants applicable to nanomaterials? We propose a way to answer these questions and move Nano EHS forward, creating a new framework for detecting, determining the fate, characterizing the hazards, and assessing the risk of engineered nanomaterials. To understand why and how these frameworks are relevant, we must first look at what nanotechnology is, examine the current state of the field, and highlight the issues inherent in studying nanotechnology.
What Is Nanotechnology?
Nanotechnology is the science of manipulating materials on the atomic and molecular level. While Eric Drexler is credited with coining the term nanotechnology in the 1980s 2, Feynman is credited with heralding its coming. In the years since Feynman's speech, focused research and development funding from governments and companies worldwide has impelled the rapidly expanding nanotechnology markets, which now include more than 1,000 commercially available products. These products either contain nanomaterials or have been produced using nanotechnology (http://www.nanotechproject.org/inventories/; see Nanomaterials Among Us: Their Risks and Benefits). The scientific community is now routinely asked to engage the public during research, which has led to the notion that nanotechnology must be innovated responsibly. This concept has become global as governmental agencies push this agenda (see, for example,http://tinyurl.com/cttu8jy). The potential applications for nanomaterials are growing exponentially, with products and processes rapidly moving out of the research laboratory and into commercial operations. Compared with traditional chemicals, risks associated with nanomaterials are largely unknown. Yet, engineered nanomaterials are being used every day in many sectors of our society and undoubtedly enter the environment.
Nanomaterials Among Us: Their Risks and Benefits
Application | Risk | Benefit |
Nanocrystals harvest light in photovoltaic devices. | Light pollution in rural areas, opportunity cost to fossil fuel economies. | Green, renewable energy, new self-lighting displays for electronic devices. |
Antimicrobial wound dressings contain nanocrystalline silver. | Release of antimicrobials into the environment, hazard to natural microbial systems. | Improved healing in wounds and reduced risk of infection. |
Sunscreens containing titanium dioxide nanomaterials are extremely effective at absorbing ultraviolet light. | Titanium hazard to intertidal organisms and sandy shore ecosystems. | Consumer preference for transparent but effective sun creams. Potential decrease in skin cancer due to increased sunscreen use. |
Metal nanomaterial supplements to increase the burn efficiency of fuels. | Respiratory exposure to nanomaterials in fuel exhausts. Long range transport of particles in the atmosphere. | Less soot from diesel vehicles and urban air pollution. Burn efficient aviation fuels. Economic saving for transport infrastructure on fuel costs. Reduced greenhouse gases. |
Medical applications of hydroxyapatite and nano-silica applications in bone reconstruction. | Durability-particles eroded from the surface may cause pathology in other internal organs in the long term. | Structural repairs to teeth and bone using a natural material already in the body (no adverse immune response). |
Nanomaterials in food packaging. | Unintended transfer of nanomaterial from the packaging to the food. Uncertain lifetime oral exposure risk. | Stronger lighter packaging to protect soft foods, antibacterial packing to improve shelf life. Increased food safety. |
Use of carbon nanotubes to improve strength and flexibility of sports equipment. | Life cycle analysis, what happens to the materials in landfill at the end of their use? | Better product that lasts longer for the consumer. Reduced sports-related injuries. |
Use of nanomaterials as catalyst in industrial processes such as coal liquefaction and producing gas. | Inadvertent incorporation of toxic catalysts in consumer products, waste disposal of catalytic converters to landfill. | Improved efficiency and economy of industrial processes. Less industrial waste/ton of production. |
Use of nanomaterials in water filtration and purification. | Unintended waterborne exposure to wildlife of engineered nanomaterials. | New sources of portable, safe drinking water in poor regions of Africa/Asia. More efficient purification systems for the water. Reduced exposure to waterborne pathogenic organisms and toxins. |
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| Figure 1. Tipping the scale: The relative size of materials in our world. Left to right: Water molecule (H20); Citrate stabilized gold sphere; Buckminster fullerene (C60); DNA; multiwalled carbon nanotube; red blood cells; penny; tennis ball. |
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Fonte: OnlineLibrary Wiley
