FrogHeart

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.