Implications of Nanotechnology for Environmental Health Research (2005) / Chapter Skim
Currently Skimming:
3 Nanotechnology: Expanding Scientific Understanding
3 Nanotechnology: Expanding Scientific Understanding
Pages 23-37
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 23... ...
There are only about 30 papers written on the environmental and health impacts of these particles; however, there is a wealth of knowledge on incidental nanoparticles and how these particles interact with biological organisms, noted Colvin. Questions remain whether the engineered nanoparticles will act as a bulk solid or a molecular system (see Toxicology below)
|
From page 24... ...
Many engineered nanomaterials have precisely controlled internal structures, which are structures of perfect solids. Over a third of the atoms in a nanoparticle are at the surface, and these are extremely reactive systems, which in some cases can generate oxygen radicals (see oxidative stress later in the chapter)
|
From page 25... ...
When cadmium selenide (CdSe) quantum dots in a liver culture model are exposed to air or ultraviolet light, hepatocyte viability decreases as assessed by mitochondrial activity of QD-treated cultures (Figure 3-1)
|
From page 26... ...
quantum dots in liver culture model is dependent on processing conditions and nanoparticle dose. Hepatocyte viability as assessed by mitochondrial activity of QD-treated cultures relative to untreated controls.
|
From page 27... ...
The potential dilemma is that not only does the immune system use super oxide radicals to kill foreign toxicants; the super oxide radicals can cause hydroxyl radicals, which can lead to DNA cleavage. The good news is that the body has some ability to prevent the undesired DNA cleavage through super oxide dismutase, part of the antioxidant defense system, noted Oberdörster.
|
From page 28... ...
aggregates due to high Van Der Waals forces, rather than discrete particles. -- David Warheit This means that if an inhaled particle with a diameter of 50100 nm forms an aggregate of 510 particle types, in terms of deposition it may have the properties of a 200500 nm particle, sug gested Warheit.
|
From page 29... ...
Toxicity of Carbon Nanotubes In a recent study, Warheit investigated the toxicity of intratracheally instilled carbon nanotubes, which are approximately 1 nm by 15 µm as a singular particle. However, due to strong electrostatic potential, they rarely exist as individual discrete particles and agglomerate into nanoropes.
|
From page 30... ...
WHAT CAN WE LEARN FROM DIESEL PARTICLES? John Froines of UCLA raised the question, does the research that scientists are doing on airborne particulate matter related health effects have relevance to understanding potential issues with respect to nanotechnology?
|
From page 31... ...
Health Endpoints There have been a number of health endpoints associated with ultra-fine particles. Animals exposed to ultra-fine particles from freeways show enhanced allergic airway responses and CNS inflammation.
|
From page 32... ...
However, to be in a position to assess risk, additional infor mation is needed regarding toxicity of the materials including: how they interact biologically in the body and what the health effects are resulting from toxicity, environmental exposure, and potential exposure routes (i.e., whether the material is inhaled, ingested or absorbed cutaneously) , noted Maynard.
|
From page 33... ...
During the same time period, the investment in environmental health and safety implications research funding had only a slight increase from 0.2 percent to less than 1 percent of total investment in nanotechnology. Balbus noted that the public expects the federal government to anticipate and to be proactive about the risks of any future commercial products and he questioned whether the funding levels were adequate for environment and health research.
|
From page 34... ...
other poorly water soluble chemicals such as PCBs -- with increased potential -- John Balbus for bioaccumulation through repeated cycle absorption, evaporation, and tran spiration. These are only two examples, but Balbus questioned whether science is in a position to answer to these ques tions, since there is a paucity of data presently.
|
From page 35... ...
NO Yes or UNKNOWN Low priority Intermediate High priority Classical toxicology priority Restrict production to No restriction on Restrict production to < 1 t a-1 production < 10 a-1 NOTE: At decision points, UNKNOWN values should be taken to equal YES FIGURE 3-2 Flow chart utilized by the European Commission on Community Health and Consumer Protection to assess solubility, ability to be transported within the body, ecotoxic probability, and other hazard probability and priorities and is assigned low, intermediate, and high priority. SOURCE: European Commission, Community Health and Consumer Protection, 2004.
|
From page 36... ...
Continuing on the examples discussed by John Balbus early in his presentation, participants also raised the examples of the times when nuclear energy was introduced in the United States and there was a lot of positive publicity about the peaceful atom which later on produced a large backlash when the public realized that there were also hazards in the new technology. Another example was when biotechnology was advertised as being absolutely safe and, again, later the public realized about the negative sides of biotechnology.
|
From page 37... ...
Finally, trust takes more than just good risk communication skills. The best way to get the public to perceive things correctly is by right action, and by a clear demonstration that everything in the power of government and industry is being done to insure protection of consumers and the environment, concluded Balbus.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.