Nanotechnology and the environment
Nanotechnology refers to the manipulation and control of matter at the nanoscale, specifically within the range of 1 to 100 nanometers. This emerging field has garnered significant public and private investment due to its potential to revolutionize various sectors, including electronics, medicine, and environmental science. While advancements in nanotechnology promise lighter materials, fuel-efficient devices, and improved medical applications, concerns linger regarding the environmental and health impacts of nanoparticles. Preliminary research indicates that nanoparticles can exhibit different properties than their larger counterparts, raising questions about their safety when they interact with living organisms and ecosystems.
The study of nanotoxicology is critical to understanding how these particles may affect human health and the environment. Some nanoparticles, like nanosilver, have demonstrated potential adverse effects on the immune system, while carbon nanotubes have been linked to tissue damage in early studies. As nanotechnology becomes more integrated into consumer products and industrial processes, the potential for increased exposure to nanoparticles has escalated, prompting calls for careful regulation and further research. Policymakers and scientists emphasize the need for a precautionary approach to navigate the unknowns of this rapidly developing field, ensuring that the benefits of nanotechnology can be harnessed without compromising environmental integrity or public health.
Nanotechnology and the environment
DEFINITION: Diverse field of science and technology that seeks to understand and control matter at dimensions of 1 to 100 nanometers
Nanotechnology receives large-scale public and private investment around the world. The field holds the promise of revolutionizing much of science and technology, but the potential impacts of the products of nanotechnology on the environment, health, and safety are poorly understood. Preliminary research findings suggest that much further study is needed.
Nanotechnology is a relatively new field concerned with a wide range of materials and processes. The increasing speeds and decreasing sizes of personal electronic devices owe much to nanotechnology, which enables the production of lighter and stronger materials that reduce energy usage and prolong the life spans of the devices made with them. Battery and lighting systems have been developed that use nanotechnology to be more fuel-efficient. Nanotechnology has also contributed to the development of improved medical diagnostic devices and drug-delivery systems. Research into the use of nanotechnology to detect pollutants and build more effective water-purification systems is ongoing. The promise of nanotechnology is immense, but the field is new, and much remains uncertain about its overall impacts on the and human health.
Definition
The term “nano” is a prefix for one-billionth, or 1 10-9, of a unit. Nanotechnology is concerned with the study, development, and control of materials at nanoscale—that is, in the range of 1 to 100 nanometers (or 1 to 100 billionths of 1 meter). Nanotechnology includes processes and instruments that engineer materials at nanoscale, and nanoparticles have at least one dimension in the nanoscale range.
Many naturally occurring materials have nanoscale dimensions, including proteins, the genetic deoxyribonucleic acid (DNA), and viruses. Volcanoes and forest fires produce nanoparticles, and many soils contain and inorganic nanoparticles. Nanoparticles are also produced by human activities, such as cigarette smoking and the burning of fuels in combustion engines. The polymer and plastics industry makes chemical molecules with nanoscale dimensions. Environmental issues associated with nanotechnology thus overlap other areas.
A significant segment of nanotechnology is concerned with newly discovered nanoparticles. These can have completely different electrical, magnetic, or biological properties compared to larger particles of the same substance. For example, gold nanoparticles can be red, blue, or gold, depending on their precise size. Titanium dioxide and zinc oxide are used in sunscreens to block the sun’s ultraviolet (UV) rays, but large particles of these substances leave a white coating on the skin; as nanoparticles, the same substances are transparent and more appealing to sunbathers. Questions have arisen, however, about what else might be different about these nanoparticles and what effects they might have when they get into the body or are washed into the environment.
Richard E. Smalley has been called the grandfather of nanotechnology. In 1986 he and others discovered a completely new form of carbon. They named it buckminsterfullerene, but as the molecules look like soccer balls, they are more commonly called buckyballs. Several sizes and shapes have been identified and collectively are called fullerenes. They are being investigated as possible devices to transport drug molecules to specific tissues and cells.
Many different kinds of nanoparticles have been developed and given names such as dendrimers, nanowires, and quantum dots. Carbon nanotubes are particularly interesting. Identified in 1991, they are highly organized carbon atoms that form sheets that roll into long tubes. Having different forms, they usually are a few nanometers wide and can be millimeters long. They are extremely strong for their weight, can transport other materials, and have unique electrical properties. They may have uses in reinforcing car and airplane bodies and in making comfortable bulletproof clothing; they may also have applications in medicine and in new battery technology. Carbon nanotubes have been at the center of early debate over the potential environmental impacts of nanotechnology.
Preliminary Nanotoxicology
Nanoparticles can enter living cells, making them useful as drugs but also raising concerns. Some nanoparticles enter the nuclei of cells, where genetic material is stored. This may have beneficial uses, but it could also lead to genetic damage. Nanoparticles smaller than 35 nanometers can penetrate the blood-brain barrier, which prevents most chemicals from reaching the brain. This property could help deliver drugs for brain disorders, but it might also cause harmful side effects.
The field of science that investigates such concerns is known as nanotoxicology. Some early nanotoxicological studies have provided worrisome results. Nanosilver has antibacterial properties and has been used in special clothing and on surfaces where might grow. Bulk silver is normally safe, but laboratory experiments have shown that nanosilver might interfere with the human immune system.
Carbon nanotubes account for much of nanoparticle manufacturing, and their production is predicted to increase dramatically. However, a 2009 review of research into the of carbon nanotubes found that only twenty-one studies had yet been conducted, and all had shown some damage to tissues and animals. None of the research studies had examined the effects of carbon nanotubes on humans.
Hardly any research has examined nanoparticles after they enter the environment from normal wear and tear or when products are discarded. One of the first studies exposed largemouth bass to buckyballs for forty-eight hours. Most of the organs of the fish were unharmed, but their brains showed evidence of oxidative damage. Because buckyballs are highly fat-soluble and thus prone to cause environmental damage, the researchers urged the widespread application of the precautionary principle to avoid the sort of environmental damage seen from earlier chemicals with similar solubility profiles.
Nanobots and Gray Goo
The vision for nanotechnology originated in a 1959 talk by American physicistRichard Feynman. He predicted the development of very fast and small computers, as well as tiny machines that could circulate through the body. Such hypothetical devices have come to be called nanobots or nanites and are commonly included in science-fiction scenarios. They also come up in discussions about the potential environmental impacts of nanotechnology.
Another early proponent of nanotechnology, K. Eric Drexler, published Engines of Creation: The Coming Era of Nanotechnology in 1986. This book had a significant impact on the development and popular understanding of nanotechnology. Drexler’s proposal, called molecular manufacturing, involved building nanomachines (or assemblers) that would make things with atomic precision. Drexler’s proposal remains scientifically controversial, with critics such as Richard Smalley asserting that the approach is physically impossible.
Others have used the idea of such assemblers to portray nanotechnology as extremely dangerous. Drexler suggested that nanomachines could be programmed to assemble copies of themselves. This would increase production but raises concerns about how to control them. Nanotechnology molecular assemblers have become associated with self-replication, although the ideas are not necessarily linked. Science-fiction authors have invented scenarios in which marauding nanobots wreak environmental havoc.
Drexler eventually distanced himself from the idea of assembler self-replication, but he coined the term “gray goo” to describe a situation in which self-replicating nanomachines get out of control and consume everything around them. In a later edition of his book, Drexler lamented how nanotechnology had become associated with so-called gray goo scenarios. He used the term in only one passage of the book, while repeatedly stressing nanotechnology’s potential either to destroy the world or to remake it, curing illness and restoring the environment.
Such grand claims make it more difficult to evaluate the real potential and actual threat of nanotechnology. A distinction must be made between “normal” nanotechnology and “futuristic” nanotechnology. Molecular assemblers and gray goo scenarios belong well into the future, although the steps that current scientists take may determine whether or when these might develop. Normal nanotechnology in the early twenty-first century focuses on recent discoveries about nanoparticles and their properties. Because of the newness of the field, much remains unknown and uncertain, either positive or negative, and practical environmental concerns are being raised.
Examining Environmental Concerns
Given the scientific uncertainty about the impacts of nanoparticles, many scientists and policy makers have called for caution in the study and use of such particles. The European Union has adopted a precautionary approach in its chemical regulatory agency and in its voluntary code of conduct for nanotechnologists. Worldwide, concerted efforts have been undertaken to understand and regulate nanoparticles. The U.S. Environmental Protection Agency launched a major research initiative in 2009 into the health and environmental concerns raised by nanotechnology.
While nanotoxicology is starting to be addressed, many remain concerned about the funding of research into environmental concerns. In the United States, the National Nanotechnology Initiative (NNI) coordinates federal investment in nanotechnology. Between 2005 and 2010, less than 4 percent of the $9 billion invested went directly to the examination of environmental, health, and safety issues. In 2008 the NNI published its strategy for such research, but the National Research Council was critical of the approach, concluding that it overestimated how much research had already been conducted and thereby underestimated the funding necessary to address environmental issues adequately.
The potential benefits of nanotechnology are enormous, but they will be realized only if concerns about possible negative health and environmental impacts are addressed. A gray goo scenario is not necessary for nanoparticles to damage the environment, and much research has yet to be done in this young field before the risks of nanotechnology are fully understood and steps can be taken to ensure that any potential harms are minimized.
During the 2010s and and 2020s, environmental scientists began working towards utilizing nanomaterials in waste management, clean energy, and various consumer products. As these materials became commonplace in the consumer market, the average person's exposure rate to nanomaterials substantially increased. Some researchers warned that consumers may experience unexpected health effects from sustained exposure to nanomaterials.f
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