Researchers at Texas Tech University have come up with a new method for detecting CNTs in soils, which will help determine their toxicity. CNTs are so small that mean outer diameters of 13nm to 16nm are common in multi-walled tubes, shown here as grains partially smeared on paper (scale in centimeters). (Source: Shaddack/Wikimedia Commons)
@Cabe: It's definitely an exaggeration to say that everybody who worked at the Johns Manville plant in Waukegan died of asbestos related problems -- but many people did, and not just people who worked in the plant. The company was careless about what it did with waste material (it was literally just strewn around the site), so there were significant amounts of airborne asbestos dust in the surrounding area. This was well after asbestos was known to be harmful.
On the other hand, a company I worked for in Chicago went bankrupt in 2002 as a result of an asbestos class-action suit. It was one of the small companies that lawyers went after once all of the big companies like Johns Manville went under. As far as I know, the company's use of asbestos had always been relatively minor, and ended in 1972, when the dangers of asebstos began to be widely known. But a few lawyers, including one who had a (now-defunct) website called MillionDollarLungs.com, saw dollar signs.
Asbestos continues to be widely used in the developing world, particularly in India, where the use of asbestos is actually expanding.
As George Santayana said, "Those who cannot remember the past are condemned to repeat it."
It is a shame what past generations left us, like these contaminated factories. Could they have known? Those 4000+ people probably all suffer from asbestos related problems. Could they have known in the past.
I agree with you all. There is no excuse for not testing for human safety in these new fabrication materials. Perhaps 4000+ people's lives will be saved with that work.
Dave, thanks for the info and links, and the perspective of one directly affected by environmental toxicity. Cabe, the toxicity potential is far, far worse with nanomaterials than with materials that have micro-sized particles, such as silicon. It's a matter of scale, for one thing: in this case, size matters enormously (pun intended). You might want to take a look at some of the background material, such as the links Dave provided or those in my previous nanomaterial legislation article, to understand how different events at the nanoscale can be from events at the microscale. It's an eye-opener.
@Cabe: Obviously everything has risks, but it's important to understand the risks, so that you can keep them under control. There are three Superfund sites within walking distance of my house. One is a former Johns Manville insulation plant that once employed 6500 people. It is still contaminated with more than 3 million cubic yards of asbestos. Another is our harbor, which is contaminated with PCBs that were used in a former die casting facility that employed more than 4000 people. Not only are the jobs gone, but we're left with the mess and its long-term effects. This is why it's important to understand the health and environmental implications of a material before employing it on a mass scale.
Great, one of the future super-materials is poised to kill us all. I suppose silicon has been killing life for decades directly and indirectly. What else is new. Perhaps the study should look at how the nano-tube compares to the material it is replacing. I'm sure as materials like this become commercialized, they will.
Tim and ervin0072002, based on the Japanese, US and European concerns about CNTs from all sources, which we covered here http://www.designnews.com/document.asp?doc_id=237995 and especially during the manufacturing process, I think the answer to Tim's question is "yes."
@Ann: You're definitely right that environmental and health impacts should be at the front of our minds when evaluating a new material. That being said, there has been a lot of work done on the toxicity of nanomaterials, particularly over the past 5-7 years. A lot of people are working on this, to ensure that we aren't opening Pandora's box.
A German research group published an article in Nature in 2006 showing that a Damascus blade produced in the 17th century contained multi-walled carbon nanotubes, as well as cementite nanowires. It's believed that the nanotubes formed in-situ during the forging process. You can read the article here.
The article mentions that cobalt, along with other alloying elements present in small amounts, played an important role in providing the steel with its distinctive microstructure.
Lou, thanks for your comments. Researching and writing this article made me think how, for the nth time, we've gone off looking for new technologies without first considering whether the (new or old) materials involved are harmful to living beings when introduced into the ecosystem, or even how likely it is that the materials can easily get into the ecosystem. It's simply not one of the first questions we ask--and I think it should be.
An in-depth survey of 700 current and future users of 3D printing holds few surprises, but results emphasize some major trends already in progress. Two standouts are the big growth in end-use parts and metal additive manufacturing (AM) most respondents expect.
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