Tag Archives: toxicology

Beginner’s guide to carbon nanotubes and nanowires

There’s a very nice Apr. 11, 2013  introductory article by David L. Chandler for the Massachusetts Institute of Technology (MIT) news office) about carbon and other nanotubes and nanowires,

The initial discovery of carbon nanotubes — tiny tubes of pure carbon, essentially sheets of graphene rolled up unto a cylinder — is generally credited to a paper published in 1991 by the Japanese physicist Sumio Ijima (although some forms of carbon nanotubes had been observed earlier). Almost immediately, there was an explosion of interest in this exotic form of a commonplace material. Nanowires — solid crystalline fibers, rather than hollow tubes — gained similar prominence a few years later.

Due to their extreme slenderness, both nanotubes and nanowires are essentially one-dimensional. “They are quasi-one-dimensional materials,” says MIT associate professor of materials science and engineering Silvija Gradečak: “Two of their dimensions are on the nanometer scale.” This one-dimensionality confers distinctive electrical and optical properties.

For one thing, it means that the electrons and photons within these nanowires experience “quantum confinement effects,” Gradečak says. And yet, unlike other materials that produce such quantum effects, such as quantum dots, nanowires’ length makes it possible for them to connect with other macroscopic devices and the outside world.

The structure of a nanowire is so simple that there’s no room for defects, and electrons pass through unimpeded, Gradečak explains. This sidesteps a major problem with typical crystalline semiconductors, such as those made from a wafer of silicon: There are always defects in those structures, and those defects interfere with the passage of electrons.

H/T Nanowerk Apr. 11, 2013 news item. There’s more to read at the MIT website and I recommend this as a good beginner’s piece since the focus is entirely on what carbon nanotubes and nanowires are , how they are formed, and which distinctive properties are theirs. You can find some of this information in the odd paragraph of a news release touting the latest research but I’m very excited to find this much explanatory material in one place.

Another very good explanatory piece, this one focused on carbon nanotubes and risk, is a video produced by Dr. Andrew Maynard for his Risk Bites series. I featured and embedded it in my Mar. 15, 2013 posting. titled, The long, the short, the straight, and the curved of them: all about carbon nanotubes.  You can also find the video in Andrew’s Mar. 14, 2013 posting on his 2020 Science blog where he also writes about the then recently released information from the US National Institute of Occupational Health and Safety on carbon nanotubes and toxicity.

Looking blue? Maybe it’s silver nanoparticles

Looking blue can mean feeling sad or it can indicate that you have argyria, a condition caused by ingesting too much silver. An Oct. 29, 2012 news item on Nanowerk about research on argyria taking place at Brown University reveals the latest insight on the cause for this condition,

Researchers from Brown University have shown for the first time how ingesting too much silver can cause argyria, a rare condition in which patients’ skin turns a striking shade of grayish blue.

“It’s the first conceptual model giving the whole picture of how one develops this condition,” said Robert Hurt, professor of engineering at Brown and part of the research team. “What’s interesting here is that the particles someone ingests aren’t the particles that ultimately cause the disorder.”

Scientists have known for years argyria had something to do with silver. The condition has been documented in people who (ill advisedly) drink antimicrobial health tonics containing silver nanoparticles and in people who have had extensive medical treatments involving silver. Tissue samples from patients showed silver particles actually lodged deep in the skin, but it wasn’t clear how they got there.

As it turns out, argyria is caused by a complex series of chemical reactions, Hurt said. His paper on the subject, authored with Brown colleagues Jingyu Liu, Zhongying Wang, Frances Liu, and Agnes Kane, is published in the journal ACS Nano (“Chemical Transformations of Nanosilver in Biological Environments” [behind a paywall]).

The Oct. 25, 2012 Brown University news release (which originated the news item) provides more detail,

Hurt and his team have been studying the environmental impact of silver, specifically silver nanoparticles, for years. They’ve found that nanosilver tends to corrode in acidic environments, giving off charged ions — silver salts — that can be toxic in large amounts. Hurt’s graduate student, Jingyu Liu (now a postdoctoral fellow at the National Institute of Standards and Technology), thought those same toxic ions might also be produced when silver enters the body, and could play a role in argyria.

To find out, the researchers mixed a series chemical treatments that could simulate what might happen to silver inside the body. One treatment simulated the acidic environment in the gastrointestinal tract; one mimicked the protein content of the bloodstream; and a collagen gel replicated the base membranes of the skin.

They found that nanosilver corrodes in stomach acid in much the same way it does in other acidic environments. Corrosion strips silver atoms of electrons, forming positively charged silver salt ions. Those ions can easily be taken into the bloodstream through channels that absorb other types of salt. That’s a crucial step, Hurt said. Silver metal particles themselves aren’t terribly likely to make it from the GI tract to the blood, but when they’re transformed into a salt, they’re ushered right through.

From there, Hurt and his team showed that silver ions bind easily with sulfur present in blood proteins, which would give them a free ride through the bloodstream. Some of those ions would eventually end up in the skin, where they’d be exposed to light.

To re-create this end stage, the researchers shined ultraviolet light on collagen gel containing silver ions. The light caused electrons from the surrounding materials to jump onto the unstable ions, returning them to their original state — elemental silver. This final reaction is ultimately what turns patients’ skin blue. The photoreaction is similar to the way silver is used in black and white photography [emphasis mine]. When exposed to light, silver salts on a photographic film reduce to elemental silver and darken, creating an image.

While I find the notion that the body’s reaction to silver is similar to the processing of silver in black and white photography, it’s the discussion about toxicity that most interests me. The scientists at Brown are suggesting that   standard ‘ingestable’ silver could be more dangerous than silver nanoparticles when they are consumed in the body,

This research, however, “would be one piece of evidence that you could treat nanoparticles in the same way as other forms of silver,” Hurt says.

That’s because the bioavailable form of silver — the form that is absorbed into the bloodstream — is the silver salt that’s made in the stomach. Any elemental silver that’s ingested is just the raw material to make that bioavailable salt. So ingesting silver in any form, be it nano or not, would have basically the same effect, Hurt said.

“The concern in this case is the total dose of silver, not what form it’s in,” Hurt said. “This study implies that silver nanoparticles will be less toxic than an equivalent amount of silver salt, at least in this exposure scenario [emphasis mine].”

This research provides more evidence supporting Dr. Andrew Maynard’s contention that creating definitions and regulations for nanomaterials based on size may not be the best approach. Here’s his response to my question (in an Oct. 24, 2011 posting) about the then newly adopted Health Canada definition (which includes size) for nanomaterials,

The problem is that, while the Health Canada is a valiant attempt to craft a definition based on the current state of science, it is still based on a premise – that size within a well defined range is a robust indicator of novel risk – that is questionable [emphasis mine].  Granted, they try to compensate for the limitations of this premise, but the result still smacks of trying to shoehorn the science into an assumption of what is important.

One can only wait as the evidence continues to mount on one side or the other. In the meantime, I don’t one can ever go wrong with BB King, one of the great blues guitar players (Blues Boys Tune),

Nanomaterials and toxicology (US Environmental Protection Agency and National Institute of Occupational Health and Safety)

It seems to be ‘toxicology and nanomaterials’ season right now. In addition to the ISO (International Standards Organization) technical report on nanomaterials and toxicology which was released in early June (mentioned in my June 4, 2012 posting), the US Environmental Protection Agency (EPA) and the US National Institute of Occupational Safety and Health (NIOSH) have released new reports.

Yesterday (July 2, 2012), the EPA posted a notice on the US Federal Register about a report, a commenting period, and a public information exchange meeting for “Nanomaterial Case Study: A Comparison of Multiwalled Carbon Nanotubes and Decabromodiphenyl Ether Flame-Retardant Coatings Applied to Upholstery Textiles.”

As I noted in an Aug. 27, 2010 posting, the EPA has adopted a very interesting approach to studying possible toxicological effects due to nanomaterials (and other materials),

Such case studies do not represent completed or even preliminary assessments; rather, they are intended as a starting point in a process to identify and prioritize possible research directions to support future assessments of nanomaterials.

Part of the rationale for focusing on a series of nanomaterial case studies is that such materials and applications can have highly varied and complex properties that make considering them in the abstract or in generalities quite difficult. Different materials and different applications of a given material could raise unique questions or issues as well as some issues that are common to various applications of a given nanomaterial or even to different nanomaterials. After several individual case studies have been examined, refining a strategy for nanomaterials research to support long-term assessment efforts should be possible. (p. 19 PDF, p. 1-1 in print version of a  US EPA silver nanomaterials draft report)

The July 3, 2012 news item on Nanowerk offers more detail about this latest case study (Note: I have removed a link),

EPA announces the release of the draft report, Nanomaterial Case Study: A Comparison of Multiwalled Carbon Nanotube and Decabromodiphenyl Ether Flame-Retardant Coatings Applied to Upholstery Textiles (External Review Draft), for public viewing and comment. This was announced in a July 2, 2012 Federal Register Notice  along with information about the upcoming public Information Exchange Meeting scheduled for October 29, 2012. The purpose of this meeting is to receive comments and questions on the draft document, as well as provide information on the draft document and a workshop process that it will be used in, which is being conducted independently by RTI International, a contractor for EPA. The deadline for comments on the draft document is August 31, 2012. [emphases mine]

The notice on the EPA website offers details and extensive links to satisfy your information needs on this matter,

The draft document is intended to be used as part of a process to identify what is known and, more importantly, what is not yet known that could be of value in assessing the broad implications of specific nanomaterials. Like previous case studies (see History/ Chronology below [on the EPA website]), this draft case study on multiwalled carbon nanotubes (MWCNTs) is based on the comprehensive environmental assessment (CEA) approach, which consists of both a framework and a process. Unlike previous case studies this case study incorporates information about a traditional (i.e., “non-nano-enabled”) product, against which the MWCNT flame-retardant coating applied to upholstery textiles (i.e., the “nano-enabled” product) can be compared. The comparative element serves dual-purposes: 1) to provide a more robust database that facilitates identification of data gaps related to the nano-enabled product and 2) to provide a context for identifying key factors and data gaps for future efforts to evaluate risk-related trade-offs between a nano-enabled and non-nano-enabled product.

This draft case study does not represent a completed or even a preliminary assessment of MWCNTs; rather, it uses the CEA framework to structure information from available literature and other resources (e.g., government reports) on the product life cycle, fate and transport processes in various environmental media, exposure-dose characterization, and impacts in human, ecological, and environmental receptors. Importantly, information on other direct and indirect ramifications of both primary and secondary substances or stressors associated with the nanomaterial is also included when available. The draft case study provides a basis for the next step of the CEA process, whereby collective judgment is used to identify and prioritize research gaps to support future assessment efforts that inform near-term risk management goals.

Meanwhile, NIOSH has released a safety guide (from the June 29, 2012 news item on Nanowerk),

The National Institute for Occupational Safety and Health (NIOSH) has published “General Safe Practices for Working with Engineered Nanomaterials in Research Laboratories” (pdf).

With the publication of this document, NIOSH hopes to raise awareness of the occupational safety and health practices that should be followed during the synthesis, characterization, and experimentation with engineered nanomaterials in a laboratory setting. The document contains recommendations on engineering controls and safe practices for handling engineered nanomaterials in laboratories and some pilot scale operations. This guidance was designed to be used in tandem with well-established practices and the laboratory’s chemical hygiene plan. As our knowledge of nanotechnology increases, so too will our efforts to provide additional guidance materials for working safely with engineered nanomaterials.

Here is more information  from the executive summary of the General Safe Practices for Working with Engineered Nanomaterials in Research Laboratories,

Risk Management

Risk management is an integral part of occupational health and safety. Potential expo­sures to nanomaterials can be controlled in research laboratories through a flexible and adaptive risk management program. An effective program provides the framework to anticipate the emergence of this technology into laboratory settings, recognize the po­tential hazards, evaluate the exposure to the nanomaterial, develop controls to prevent or minimize exposure, and confirm the effectiveness of those controls.

Hazard Identification

Experimental animal studies indicate that potentially adverse health effects may result from exposure to nanomaterials. Experimental studies in rodents and cell cultures have shown that the toxicity of ultrafine particles or nanoparticles is greater than the toxicity of the same mass of larger particles of similar chemical composition.

Research demonstrates that inhalation is a significant route of exposure for nanoma­terials. Evidence from animal studies indicates that inhaled nanoparticles may deposit deep in lung tissue, possibly interfering with lung function. It is also theorized that nanoparticles may enter the bloodstream through the lungs and transfer to other or­gans. Dermal exposure and subsequent penetration of nanomaterials may cause local or systemic effects. Ingestion is a third potential route of exposure. Little is known about the possible adverse effects of ingestion of nanomaterials, although some evidence sug­gests that nanosized particles can be transferred across the intestinal wall.

Exposure Assessment

Exposure assessment is a key element of an effective risk management program. The ex­posure assessment should identify tasks that contribute to nanomaterial exposure and the workers conducting those tasks. An inventory of tasks should be developed that in­cludes information on the duration and frequency of tasks that may result in exposure, along with the quantity of the material being handled, dustiness of the nanomaterial, and its physical form. A thorough understanding of the exposure potential will guide exposure assessment measurements, which will help determine the type of controls re­quired for exposure mitigation.

Exposure Control

Exposure control is the use of a set of tools or strategies for decreasing or eliminating worker exposure to a particular agent. Exposure control consists of a standardized hi­erarchy to include (in priority order): elimination, substitution, isolation, engineering controls, administrative controls, or if no other option is available, personal protective equipment (PPE).

Substitution or elimination is not often feasible for workers performing research with nanomaterials; however, it may be possible to change some aspects of the physical form of the nanomaterial or the process in a way that reduces nanomaterial release.

Isolation includes the physical separation and containment of a process or piece of equipment, either by placing it in an area separate from the worker or by putting it within an enclosure that contains any nanomaterials that might be released.

Engineering controls include any physical change to the process that reduces emissions or exposure to the material being contained or controlled. Ventilation is a form of engi­neering control that can be used to reduce occupational exposures to airborne particu­lates. General exhaust ventilation (GEV), also known as dilution ventilation, permits the release of the contaminant into the workplace air and then dilutes the concentration to an acceptable level. GEV alone is not an appropriate control for engineered nano­materials or any other uncharacterized new chemical entity. Local exhaust ventilation (LEV), such as the standard laboratory chemical hood (formerly known as a laboratory fume hood), captures emissions at the source and thereby removes contaminants from the immediate occupational environment. Using selected forms of LEV properly is ap­propriate for control of engineered nanomaterials.

Administrative controls can limit workers’ exposures through techniques such as us­ing job-rotation schedules that reduce the time an individual is exposed to a substance. Administrative controls may consist of standard operating procedures, general or spe­cialized housekeeping procedures, spill prevention and control, and proper labeling and storage of nanomaterials. Employee training on the appropriate use and handling of nanomaterials is also an important administrative function.

PPE creates a barrier between the worker and nanomaterials in order to reduce expo­sures. PPE may include laboratory coats, impervious clothing, closed-toe shoes, long pants, safety glasses, face shields, impervious gloves, and respirators.

Other Considerations

Control verification or confirmation is essential to ensure that the implemented tools or strategies are performing as specified. Control verification can be performed with traditional industrial hygiene sampling methods, including area sampling, personal sampling, and real-time measurements. Control verification may also be achieved by monitoring the performance parameters of the control device to ensure that design and performance criteria are met.

Other important considerations for effective risk management of nanomaterial expo­sure include fire and explosion control. Some studies indicate that nanomaterials may be more prone to explosion and combustion than an equivalent mass concentration of larger particles.

Occupational health surveillance is used to identify possible injuries and illnesses and is recommended as a key element in an effective risk management program. Basic medical screening is prudent and should be conducted under the oversight of a qualified health-care professional. (pp. 9 – 11 PDF or pp. vii – ix in print)

The guidance as per the executive summary seems to rely heavily on what I imagine are industrial hygiene practices that should be followed whether or not laboratories are researching nanomaterials.

A few thoughts on business and nanotechnology

In my response to a comment on yesterday’s posting I was not able to address the issue of  business’ role in nanotechnology safety efforts raised by this sentence,

Parents won’t leap for joy over the suggestion that their children must be exposed to these products, lest a company’s opportunity to move forward in marketing these products for profit be stymied.

As I don’t want to be misleading, it should be noted that the commenter is critical of my stance on risk and nanosunscreens and was using this comment to buttress a more comprehensive argument.

Reading the [July 7, 2011 corrected for grammar] comment earlier today was coincidental with my discovery yesterday of an article by a business owner (Scott Rickert, President and Chief Executive Officer of Nanofilm) about the proposed nanomaterials definitions in bills before the US House of Representatives and Senate (previously mentioned on this blog here).  From Taking the NanoPulse — Toxic Substance Meets Poison Thinking; New toxics legislation aims for safe. But is it sound? (Industry Week website) where Rickert discusses the Safe Chemicals bills and nanotechnology,

… for those of us in the nanotechnology field, there’s an additional wrinkle beyond the chemical formula of our products. Both the House and Senate version of the bill now include size, size distribution, shape and surface structure in the definition of a chemical’s “substance characteristic.” That means that over and above concerns about the chemical formula a nanotechnology company may be using, it may become suspect simply because of its nanoscale charactertics.

Am I worried? No. I know the people in this industry and I believe we have a track record that shows our care at policing ourselves. We’re not monsters. We have families, children and grandchildren, too. Make no mistake, we’re concerned about environmental health and safety in our industry. [emphasis mine] We have rules and programs in place. In addition, companies like mine have been working in special new voluntary reporting programs with the EPA. And, heaven knows, our whole industry has been educating scientists, governments, special interest groups and the general public about nanotechnology for a decade or more.

I think both the commenter and Rickert are right in entirely different ways and somewhat wrong in exactly the same way. Rickert goes on,

So what’s keeping me up at night? Not worries about toxicity and nanotechnology. We can handle that. I’m worried about toxicity in the law-making process. One of the Senate authors of the Bill says, “America’s system for regulating industrial chemicals is broken… Parents are afraid because hundreds of untested chemicals are found in their children’s bodies.”

Is that really where we want to start? Throwing open the door to panic — on both sides? I sat in on a nanotechnology industry conference call recently and the fear of a “witch hunt” was palpable.

If parents are terrified, they’re in the same boat as honest, responsible companies that are making products that improve lives and have long been committed to health and environmental causes. Do you think in this age of BP oil spills and late-night law-firm mesothelioma infomercials that businesses aren’t aware that preventing a problem is better than paying for it later?

To answer Rickert’s question, I think companies are quite aware of the risks and quite willing to pass them on to consumers and citizens in pursuit of an extra dollar.  With that, I’ve agreed with the commenter and now I’m going to agree with Rickert, there are honest responsible companies run by people who care about the environment and health.

Neither the commenter nor Rickert make a distinction I want to introduce about companies/businesses. A vast gulf exists between a small to medium-sized business and a multinational enterprise in terms of revenue and economic impact, perspective on responsibility, connections to their communities, and so on. Someone who’s built up their own business in their community is quite likely to have a different take on acceptable risks than someone who lives a continent away and has no direct ongoing contact with the community in which the business is operating.

Take for example,  Tony Hayward, Group Chief Executive, BP Oil. As I write this, BP Canada (BP Oil’s Canadian subsidiary) has started work on on a well for their coalbed methane project  in an area of British Columbia (Canada) that lies between the internationally famous Banff National Park and Waterton-Glacier International Peace Park which provides a corridor for mountain-dwelling wildlife who move between the two parks. From the news item on CBC (Canadian Broadcasting Corporation) News,

As oil continues to gush from a BP wellhead in the Gulf of Mexico, critics say the company has quietly broken ground on a controversial project in B.C.’s Rocky Mountains.

Opponents of the Mist Mountain project say they were surprised to find that BP Canada, an arm of the BP group of companies, began construction earlier this month on an exploratory well for its coalbed methane project near Fernie, B.C.

But Hejdi Feick, the director of communications for BP Canada, said British Columbians can be reassured that the company is a good corporate citizen.

“We are absolutely committed to doing this right,” she said Tuesday. “We have been very open and accessible over the last three years.”

That is little comfort for [Ryland] Nelson (from the group Wildsight), who said BP had promised to consult with the public every step of the way yet he only learned construction was underway when he went to the site Monday.

Nelson said the contractor on site told him they hope to bring in drilling equipment by the end of the month and start drilling this summer.

“Here they are, they’ve been working for nearly two weeks and nobody knew anything about it,” he said.

Remarkable here is how thoroughly tone deaf the company representative is to the reception this initiative is likely to enjoy. (By the way, I live in British Columbia.)

My point is that you can’t lump all businesses together as being thoroughly unethical in the pursuit of the almighty buck nor can you lump them together as honest, ethical entities being run by people who aren’t “monsters.” (Note: I believe that Rickert was using the word to make a point about business owners being people too. I have ruthlessly extracted that word from its natural placement to suggest that while  Hayward and his ilk may or may not be monsters, the consequences of their actions in the Gulf are monstrous.)

In the discussion about nanotechnology and safety I think we need to consider as many perspectives as possible without condemning everyone who represents business interests or being unduly naïve about competing interests. I do encourage you to read Ricket’s critique of the two Safe Chemicals bills as he brings up issues that would never have occurred to me and, I imagine, others who are not directly involved in the production of nanotechnology-enabled products.

Comparing nanomaterials definitions: US and Canada

In light of yesterday’s (April 26, 2010) posting about Health Canada and their nanomaterials definition, Andrew Maynard’s April 23, 2010 post at 2020 Science (blog) is quite timely. Andrew has some details about new nanomaterials definitions being proposed in the both the US Senate and House of Representatives so that their Toxic Substances Control Act can be amended. From Andrew’s posting, an excerpt about the proposed House bill,

The House draft document is a little more explicit. It recommends amending section 3(2) of the original act with:

“(C) For purposes of this Act, such term may include more than 1 form of a substance with a particular molecular identity as described in sub-paragraph (A) if the Administrator has determined such forms to be different substances, based on variations in the substance characteristics. New forms of existing chemical substances so determined shall be considered new chemical substances.” (page 6)

with the clarification that

“The term ‘substance characteristic’ means, with respect to a particular chemical substance, the physical and chemical characteristics that may vary for such substance, and whose variation may bear on the toxicological properties of the chemical substance, including—

(A) chemical structure and composition

(B) size or size distribution

(C) shape

(D) surface structure

(E) reactivity; and

(F) other characteristics and properties that may bear on toxicological properties” (page 11)

Both the Senate bill and the House discussion document provide EPA with the authority to regulate any substance that presents a new or previously unrecognized risk to human health as a new substance. This is critical to ensuring the safety of engineered nanomaterials, where risk may depend on more than just the chemistry of the substance. But it also creates a framework for regulating any new material that presents a potential risk – whether it is a new chemical, a relatively simple nanomaterial, a more complex nanomaterial – possibly one that changes behavior in response to its environment, or a novel material that has yet to be invented. In other words, these provisions effectively future-proof the new regulation.

I prefer the definition in the draft House of Representatives bill to Health Canada’s because of its specificity and its future-oriented approach. Contrast their specificity with this from the Interim Policy Statement on Health Canada’s Working Definition for Nanomaterials:

Health Canada considers any manufactured product, material, substance, ingredient, device, system or structure to be nanomaterial if:

1. It is at or within the nanoscale in at least one spatial dimension, or;

2. It is smaller or larger than the nanoscale in all spatial dimensions and exhibits one or more nanoscale phenomena.

For the purposes of this definition:

* The term “nanoscale” means 1 to 100 nanometres, inclusive;

* The term “nanoscale phenomena” means properties of the product, material, substance, ingredient, device, system or structure which are attributable to its size [emphasis mine] and distinguishable from the chemical or physical properties of individual atoms, individual molecules and bulk material; and,

* The term “manufactured” includes engineering processes and control of matter and processes at the nanoscale.

You’ll notice the House of Representatives’ draft bill offers five elements to the description (chemical composition, size or size distribution [emphasis mine], shape, surface structure, reactivity, and other characteristics and properties that may bear on toxicological properties). So in the US they include elements that have been identified as possibly being a problem and leave the door open for future discovery.

The proposed legislation has another feature, Andrew notes that,

Both the Senate bill and the House discussion document provide EPA with the authority [emphasis mine] to regulate any substance that presents a new or previously unrecognized risk to human health as a new substance. This is critical to ensuring the safety of engineered nanomaterials, where risk may depend on more than just the chemistry of the substance. But it also creates a framework for regulating any new material that presents a potential risk – whether it is a new chemical, a relatively simple nanomaterial, a more complex nanomaterial – possibly one that changes behavior in response to its environment, or a novel material that has yet to be invented. In other words, these provisions effectively future-proof the new regulation.

As far as I can recall, Peter Julian’s (MP – NDP) tabled draft bill for nanotechnology regulation in Canada does not offer this kind of ‘future-proofing’ although it could be added if it is ever brought forward for debate in the House of Commons. Given the quantity of public and political discussion on nanotechnology (and science, in general) in Canada, I doubt any politician could offer those kinds of amendments to Julian’s proposed bill.

As for Canada’s proposed nanomaterials reporting plan/inventory/scheme, Health Canada’s proposed definition’s vagueness makes compliance difficult. Let me illustrate what I mean while I explain why I highlighted ‘size distribution’ in the House of Representatives draft bill by first discussing Michael Berger’s article on Nanowerk about environment, health and safety (EHS) research into the toxicological properties of nanomaterials. From Berger’s article,

” What we found in our work is that nanomaterials purchased from commercial sources may not be as well characterized as indicated by the manufacturer,” Vicki H. Grassian, a professor in the Department of Chemistry at the University of Iowa, tells Nanowerk. “For example, it might be stated that a certain nanoparticle is being sold as 30 nm in diameter and, although ’30 nm’ might be close to the average diameter, there is usually a range of particle sizes that can extend from as much as small as 5 nm to as large as 300 nm. [emphases mine]”

That’s size distribution and it reveals two problems with a reporting plan/inventory/scheme that uses a definition that sets the size within a set range. (Julian’s bill has the same problem although his range is 1 to 1000 nm.) First, what happens if you have something that’s 1001 nm? This inflexible and unswerving focus on size will frustrate the intent both of the reporting plan and of Julian’s proposed legislation. Second, how can a business supply the information being requested when manufacturers offer such a wide distribution of sizes in  products where a uniform size is claimed? Are businesses going to be asked to measure the nanomaterials? Two or three years or more after they received the products? [Aug.4.10 Note: Some grammatical changes made to this paragraph so it conveys my message more clearly.]

Then Berger’s article moves onto another issue,

Reporting their findings in a recent paper in Environmental Toxicology and Chemistry (“Commercially manufactured engineered nanomaterials for environmental and health studies: Important insights provided by independent characterization”), among other problems Grassian and first author Heaweon Park also discuss the issue of batch-to-batch variability during the production of nanoparticles and that some nanomaterials which were being sold as having spherical morphology could contain mixed morphologies such as spheres and rods [emphases mine].

That’s right, you may not be getting the same shape of nanoparticle in your batch. This variability should not pose a problem for the proposed reporting plan/inventory/scheme since shape is not mentioned in Health Canada’s definition but it could bear on toxicology issues which is why a plan/inventory/scheme is being proposed in the first place.

Interestingly, the only ‘public consultation’ meeting that Health Canada/Environment Canada has held appears to have taken place in 2007 with none since and none planned for the future (see my April 26, 2010 posting).

Apparently, 3000 stakeholders have been contacted and asked for responses. I do wonder if an organization like Nano Quebec has been contacted and counted not as a single stakeholder but as representing its membership numbers (e.g. 500 members = 500 stakeholders?) whatever they may be. There is, of course, a specific Health Canada website for this interim definition where anyone can offer comments. It takes time to write a submission and I’m not sure how much time anyone has to devote to it which is why meetings can be very effective for information gathering especially in a field like nanotechnology where the thinking changes so quickly. 2007 seems like a long time ago.

Finally, Dexter Johnson on his Nanoclast blog is offering more perspective on the recent Andrew Schneider/National Nanotechnology Initiative dust up. Yes, he gave me a shout out (and I’m chuffed) and he puts the issues together to provide a different perspective on journalistic reporting environment, health and safety issues as they relate to nanotechnology along with some of the issues associated with toxicology research.