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Can Asbestos Help Us Understand Nanotoxicity?
Roland Piquepaille writes "Occupational Hazards is running an interesting article about how using our knowledge of asbestos could help us to assess the risks from nanoparticles, or their nanotoxicity. Today, it's unknown if nanomaterials under development are dangerous to human beings or to our environment. Some people think that nanoparticles can move to our lungs or our brains, presenting a significant threat to our health. Other scientists think there is no danger because we have been exposed to nanoparticles for thousands of years, such as ashes from volcanic eruptions. For example, nanotubes which are now used for many industrial developments, have similar shapes as fibers like asbestos, being long and extremely thin. And like nanomaterials today, asbestos was considered as harmless when humans were exposed to it. While the comparison has some merit, more research needs to be done before drawing any conclusion."
Weird, occupationalhazards.com isn't registered to Roland Piquepaille. What's the catch?
This looks to be the second article in a row from the esteemed Monsieur Piquepaille that doesn't link to an article in his blog. Check out his story posting history:
Can asbestos help us understand nanotoxicity? Wed Oct 19, '05 12:23 PM
Pillows Dangerous for Your Health Sat Oct 15, '05 12:28 PM
Molecular Gastronomy, The Science of Cooking Mon Aug 29, '05 11:32 AM
The Eyes of the Space Shuttle Wed Aug 03, '05 12:58 PM
BIG gap between the two latest non-self-referential stories, and the weekly shameless self-promotion that used to be his trademark.
I suspect that somebody either gave Mr. P a stern talking-to, or more likely the editors just quit accepting his stories. Now, he's back, chastened and better for it. You've got to admit, the guy has an eye for science stories. He's just got to have confidence that if he posts good stuff, the click-throughs to his main page (linked appropriately to his name) will follow in time.
I'm all for shameless self-promotion, of course, but I'm content with the URL link in the post heading. Well, mostly...
Stressed? Me? Of course not. Stress is what a rubber band feels before it breaks, silly.
The chances are minute.
"Other scientists think there is no danger because we have been exposed to nanoparticles for thousands of years, such as ashes from volcanic eruptions. " /sarcasm on/ /sarcasm off/
And humans haven't had ANY as of yet unexplained health problems over those thousands of years either.
I think it was a bloody shame that the EPA declared New York's air safe to breath after the attack on the World Trade Center, when trillions of nano-toxins were released into the air for cleanup and emergency crews to inhale. We're going to see more of New York Lung, in the years to come.
Saskboy's blog is good. 9 out of 10 dentists agree.
Plasticisers, stabilizing agents, enzymes, catalysts and all these wonderful pharmecuticals that we consume and then pee into the environment are also nanomachines, just ones built with bulk chemistry rather than direct nanoscale assembly.
:v)
Didn't we ought to focus on what they do in the environment, rather than propagate scare stories about future nanomachines that can be pre-programmed to safely degrade?
Vik
I'm not sure if asbestos is an appropriate analog for nano-based respiratory hazards. When Dr. Irving J. Seilkoff published his report on the link between asbestos and respiratory ailments, there was already an abundant record of impairment in the form of asbestosis. Asbestosis is a scarring and sedimentation of the lung due to particulate inhalation. It is in a general family of respiratory ailments known as pneumoconiosis. That group includes silicosis (affects quarry workers) and black lung (coal miners). The link that Seilkoff is credited with is the connection of asbestos to lung cancer, which is has only one known asbestiform species in direct connection: crocidolite. This blue amphibole was used in ship construction and in homes in and around Australia (sorry mates!). This asbestiform mineral has been directly connected to one of the most virulent forms of lung cancer, mesothelioma. This cancer of the plural lining is fatal within months of diagnosis.
Connections between other asbestiform minerals and cancer is more complex. Tremolite and serpentenite have also been linked to lung cancer, but the connection is much more tenuous. Another factor that would complicate the study of asbestos as an analog is the size: an asbestos fiber is counted for toxicological purposes only when it fits a 5:1 aspect ratio and is >5 micron in length. That is the geometry that is most likely to fit into the alveoli. This deep penetration of asbestos into the tissues of the lung is presumed to be the mechanism that leads to cancer. Plaques form around the embedded spines of asbestos as microphages attack and envelope the fibers. This process leads to a general lessening of the effective surface area for gas transfer leading to shortness of breath. The mechanics leading to cancer, however, are dubious and have plagued researchers for more than two decades.
I can't see how the study of asbestos can illuminate any area of occupational health. I can, however, see how injury claims attorneys would use the experience of asbestos litigation in any future attack on the nano-industry.
"Rocky Rococo, at your cervix!"
why asbestos causes harm. Is the the morphology (shape) of it that is the key?
A doc friend of mine told me asbestos particles are long and pointy and act as minute glass shards inside the lung alveoles, and they pierce cells over and over as the lungs open and collapse during respiration. Cells repair themselves all the time, but under these repeated micro-stresses, they have to do it a whole lot more, and eventually fail to do it correctly and turn into cancer cells.
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
is that (at least with buckyballs and nanotubes) they're non-biodegradable (in this they're similar to asbestos). I recall watching the photo of a macrophage destroyed because it tried to swallow an asbestos particle.
The questions to be asked are:
Can the nanoparticles destroy the human cells, or alter their DNA as a side effect?
Can they clutter in the bloodstream or inside the organs?
While I am sure there are risks to nano technology, I think the real force driving all this "concern" is plan and simple greed.
Nano technology is what's called a "disruptive" technology. That means that it will enable people to do things for pennies on the dollar that used to cost billions. Because of this it threatens what is called "barriers to entry" for many large corporations. According to business 101, the most profitable businesses have high barriers to entry that help keep competitors out and lock profits in.
The only problem is that when a company can't compete off of it's "natural" barriers to entry, then it's only option is to compete off of "regulatory" barriers to entry. Hence the strong incentives and financial pressure to make sure nano technology is a super overregulated industry before it even exits the starting gate.
So now all the other "concerns" about nano technology that keep poping up should be far more clear.
Nanotoxicity? If you ask me, anyone stupid enough to eat their iPod deserves what they get.
"In a 32-bit world, you're a 2-bit user. You've got your own newsgroup, alt.total.loser." -Weird Al
That study is somewhat old hat. Have a look here and you'll see that the mechanism is now understood.
:v)
In short, you can make toxic, or non-toxic buckyballs. The more bits you dangle on the outside of the buckyballs, the less toxic they become. Nanomachine designers will be aware of this and act accordingly.
Vik
I work for the EPA and happen to know a couple people looking into the health effects (in mice) of fine particulates and are just starting a new project to look at diesel particles. My fellow postdoc friend has been smelling like diesel a lot lately. The odor is really quite a nice accompanyment to lunch :)
The problem with abating diesel particulate pollution is that a lot of people will likely bitch loudly about the cost of prevention or switching to a less polluting technology. It is a lot easier to study the potential effects of a new technology before it gains widespread adoption rather than trying to put the genie back in the bottle.
I live in NYC, and I don't trust the EPA to tell me that nanoparticles are safe. They lied to us after 9/11/2001 about the poisonous air. They lied to the heroic volunteers and police/fire/EMTs who could have worn masks while digging in the rubble. Instead thousands of people are walking testimonials to the EPA's lies about air pollution. I see them every day. The EPA's got a lot of work to recover its credibility. And I haven't seen anything to convince me that they're on that path.
--
make install -not war
The dangers of asbestos were actualy knowns since as early as 1898, when Lucy Dean, one of the first women inspectors for factories in the UK wrote about asbestos work as one of the top four dusty occupations which came under observation that year 'on account of their easily demonstrated danger to the health of workers and because of ascertained cases of injury of brinchial tubes and lungs'.
o rt_2001_22/en/issue-22-part-05.pdf for more informations about asbestos and the problems it's use created.
Similar observations followed in the years 1909 and 1910 and were widly circulated amongst policy-makers and politicans. By 1918 insurance companies in Canada and the United States declined insurance cover for asbestos workers 'due to the assumed injourious conditions in the industry'.
I repeat; the danger of asbestos was known from the very beginning and shorty thereafter insurance companies decliend to cover asbestos damage. That was in the 1920s. Asbestos was however used into the 1980 as a cheap and fire resistant material.
I think we should learn from the mistakes in the past and try not to repeat them.
Read this http://reports.eea.eu.int/environmental_issue_rep
It's not just the poking of holes in cells. Membranes self heal pretty well. The other thing to take into account is that macrophages try to distroy the foreign matter by releasing chemicals like hydrogen peroxide. Those damaging chemicals can get into the normal cells via the holes punched in the membranes and damage the DNA inside, which could lead to cancer.