Tag Archives: nano silver

The Canadian nano scene as seen by the OECD (Organization for Economic Cooperation and Development)

I’ve grumbled more than once or twice about the seemingly secret society that is Canada’s nanotechnology effort (especially health, safety, and environment issues) and the fact that I get most my information from Organization for Economic Cooperation and Development (OECD) documents. That said, thank you to Lynne Bergeson’s April 8, 2016 post on Nanotechnology Now for directions to the latest OECD nano document,

The Organization for Economic Cooperation and Development recently posted a March 29, 2016, report entitled Developments in Delegations on the Safety of Manufactured Nanomaterials — Tour de Table. … The report compiles information, provided by Working Party on Manufactured Nanomaterials (WPMN) participating delegations, before and after the November 2015 WPMN meeting, on current developments on the safety of manufactured nanomaterials.

It’s an international roundup that includes: Australia, Austria, Belgium, Canada, Germany, Japan, Korea, the Netherlands, Switzerland, Turkey, United Kingdom, U.S., and the European Commission (EC), as well as the Business and Industry Advisory Committee to the OECD (BIAC) and International Council on Animal Protection in OECD Programs (ICAPO).

As usual, I’m focusing on Canada. From the DEVELOPMENTS IN DELEGATIONS ON THE SAFETY OF MANUFACTURED NANOMATERIALS – TOUR DE TABLE Series on the Safety of Manufactured Nanomaterials No. 67,

National  developments  on  human  health  and  environmental  safety  including  recommendations, definitions, or discussions related to adapting or applying existing regulatory systems or the drafting of new laws/ regulations/amendments/guidance materials A consultation document on a Proposed Approach to Address Nanoscale Forms of Substances on the Domestic  Substances  List was  published  with  a  public  comment  period  ending on  May  17,  2015. The proposed approach outlines the Government’s plan to address nanomaterials considered in commerce in Canada (on  Canada’s  public inventory).  The  proposal is a stepwise  approach to  acquire  and  evaluate information,  followed  by  any  necessary  action. A  follow-up  stakeholder  workshop  is  being  planned  to discuss  next  steps  and  possible  approaches  to prioritize  future  activities. The  consultation document  is available at: http://www.ec.gc.ca/lcpe-cepa/default.asp?lang=En&n=1D804F45-1

A mandatory information gathering survey was published on July 25, 2015. The purpose of the survey is to collect information to determine the commercialstatus of certain nanomaterials in Canada. The survey targets  206  substances  considered  to  be  potentially  in commerce  at  the  nanoscale. The  list  of  206 substances was developed using outcomes from the Canada-United States Regulatory Cooperation Council (RCC)  Nanotechnology  Initiative  to  identify nanomaterial  types. These  nanomaterial  types  were  cross-referenced  with  the Domestic  Substances  List to  develop  a  preliminary  list  of  substances  which are potentially intentionally manufactured at the nanoscale. The focus of the survey aligns with the Proposed Approach to  Address  Nanoscale  Forms  of  Substances  on  the Domestic  Substances  List (see  above)  and certain  types  of  nanomaterials  were  excluded  during the  development  of  the  list  of  substances. The information  being  requested  by  the  survey  includes substance  identification,  volumes,  and  uses.  This information will feed into the Government’s proposed approach to address nanomaterials on the Domestic Substances List. Available at: http://gazette.gc.ca/rp-pr/p1/2015/2015-07-25/html/notice-avis-eng.php

Information on:

a.risk  assessment  decisions, including  the  type  of:  (a)  nanomaterials  assessed; (b) testing recommended; and (c) outcomes of the assessment;

Four substances were notified to the program since the WPMN14 – three surface modified substances and  one  inorganic  substance.  No  actions,  including  additional  data requests,  were  taken  due  to  low expected  exposures  in  accordance  with  the New  Substances  Notifications  Regulations  (Chemicals and Polymers) (NSNR) for two of the substances.  Two of the substances notified were subject to a Significant New Activity Notice. A Significant New Activity notice is an information gathering tool used to require submission  of  additional  information  if  it  is suspected  that  a  significant  new  activity  may  result in  the substance becoming toxic under the Canadian Environmental Protection Act, 1999.

b.Proposals, or modifications to previous regulatory decisions

As  part  of  the  Government’s  Chemicals  Management Plan,  a  review  is  being  undertaken  for  all substances  which  have  been  controlled through  Significant  New  Activity  (SNAc)  notices (see  above).  As part  of  this  activity,  the  Government  is  reviewing past  nanomaterials  SNAc  notices  to  see  if  new information  is  available  to  refine  the  scope  and information  requirements.    As  a  result  of  this  review, 9 SNAc  notices  previously  in  place  for  nanomaterials have  been  rescinded.    This  work  is  ongoing,  and  a complete review of all nanomaterial SNAcs is currently planned to be completed in 2016.

Information related to good practice documents

The Canada-led,  ISO  standards project, ISO/DTR  19716 Nanotechnologies — Characterization  of cellulose  nanocrystals, [emphasis mine] initiated  in  April 2014, is  now at Committee  Draft  (CD)  3-month  ISO ballot, closing    Aug 31, 2015. Ballot comments will be addressed during JWG2 Measurement and Characterization working  group meetings  at  the 18th Plenary  of  ISO/TC229, Nanotechnologies,  being held in Edmonton, Alberta, Sep. 28 – Oct. 2, 2015.

Research   programmes   or   strategies   designed   to  address   human   health   and/   or environmental safety aspects of nanomaterials

Scientific research

Environment Canada continues to support various academic and departmental research projects. This research has to date included studying fate and effects of nanomaterials in the aquatic, sediment, soil, and air  compartments. Funding  in  fiscal  2015-16  continues  to  support  such  projects,  including  sub-surface transportation, determining key physical-chemical parameters to predict ecotoxicity, and impacts of nano-silver [silver nanoparticles]  addition  to  a  whole  lake  ecosystem [Experimental Lakes Area?]. Environment  Canada  has  also  partnered  with  the National Research  Council  of  Canada  recently  to  initiate  a project  on  the  development  of  test  methods  to identify surfaces of nanomaterials for the purposes of regulatory identification and to support risk assessments. In addition,  Environment  Canada  is  working  with  academic laboratories in  Canada  and  Germany  to  prepare guidance to support testing of nanoparticles using the OECD Test Guideline for soil column leaching.

Health  Canada  continues  its  research  efforts  to  investigate  the  effects  of  surface-modified  silica nanoparticles. The   aims   of   these   projects   are  to:   (1) study the importance of size and surface functionalization;  and  (2)  provide a genotoxic profile and  to  identify  mechanistic  relationships  of  particle properties  to  elicited  toxic  responses.  A manuscript reporting  the in  vitro genotoxic,  cytotoxic and transcriptomic  responses  following  exposure  to  silica  nanoparticles  has  recently  been  submitted to  a  peer reviewed journal and is currently undergoing review. Additional manuscripts reporting the toxicity results obtained to date are in preparation.

Information on public/stakeholder consultations;

A consultation document on a Proposed Approach to Address Nanoscale Forms of Substances on the Domestic  Substances  List was  published  with a  public  comment  period ending  on May  17,  2015  (see Question  1).  Comments  were  received  from approximately  20  stakeholders  representing  industry and industry  associations,  as  well  as  non-governmental  organizations. These  comments  will  inform  decision making to address nanomaterials in commerce in Canada.

Information on research or strategies on life cycle aspects of nanomaterials

Canada, along with Government agencies in the United States, Non-Governmental Organizations and Industry,  is  engaged  in  a  project  to  look  at releases  of  nanomaterials  from  industrial  consumer  matrices (e.g., coatings). The objectives of the NanoRelease Consumer Products project are to develop protocols or
methods (validated  through  interlaboratory  testing) to  measure  releases  of  nanomaterials  from  solid matrices as a result of expected uses along the material life cycle for consumer products that contain the nanomaterials. The  project  is  currently  in  the  advanced  stages  of Phase  3  (Interlaboratory  Studies).  The objectives of Phase 3 of the project are to develop robust methods for producing and collecting samples of CNT-epoxy  and  CNT-rubber  materials  under  abrasion  and  weathering scenarios,  and  to  detect  and quantify, to the extent possible, CNT release fractions. Selected laboratories in the US, Canada, Korea and the European Community are finalising the generation and analysis of sanding and weathering samples and the    results    are    being    collected    in    a   data    hub    for    further    interpretation    and    analysis.

Additional details about the project can be found at the project website: http://www.ilsi.org/ResearchFoundation/RSIA/Pages/NanoRelease1.aspx

Under the OECD Working Party on Resource Productivity and Waste (WPRPW), the expert group on waste containing nanomaterials has developed four reflection papers on the fate of nanomaterials in waste treatment  operations.  Canada  prepared the  paper  on  the  fate  of  nanomaterials in  landfills;  Switzerland on the  recycling  of  waste  containing  nanomaterials;  Germany  on  the  incineration  of  waste  containing nanomaterials;  and  France  on  nanomaterials  in wastewater  treatment.  The  purpose  of  these  papers is to provide  an  overview  of  the  existing  knowledge  on the  behaviour  of  nanomaterials  during  disposal operations and identify the information gaps. At the fourth meeting of the WPRPW that took place on 12-14 November 2013, three of the four reflection papers were considered by members. Canada’s paper was presented and discussed at the fifth meeting of the WPRPRW that took place on 8-10 December 2014. The four  papers  were  declassified  by  EPOC  in  June  2015, and  an  introductory  chapter  was  prepared  to  draw these  papers  together. The introductory  chapter  and accompanying  papers  will  be  published in  Fall  2015. At  the sixth  meeting  of  the  WPRPW  in  June – July  2015,  the  Secretariat  presented  a  proposal  for an information-sharing  platform  that  would  allow  delegates  to  share research  and  documents  related  to nanomaterials. During a trial phase, delegates will be asked to use the platform and provide feedback on its use at the next meeting of the WPRPW in December 2015. This information-sharing platform will also be accessible to delegates of the WPMN.

Information related to exposure measurement and exposure mitigation.

Canada and the Netherlands are co-leading a project on metal impurities in carbon nanotubes. A final version  of  the  report  is  expected  to  be ready for WPMN16. All  research has  been completed (e.g. all components are published or in press and there was a presentation by Pat Rasmussen to SG-08 at the Face-to-Face Meeting in Seoul June 2015). The first draft will be submitted to the SG-08 secretariat in autumn 2015. Revisions  will  be  based  on  early  feedback  from  SG-08  participants.  The  next  steps  depend  on  this feedback and amount of revision required.

Information on past, current or future activities on nanotechnologies that are being done in co-operation with non-OECD countries.

A webinar between ECHA [European Chemicals Agency], the US EPA [Environmental Protection Agency] and Canada was hosted by Canada on April 16, 2015. These are  regularly  scheduled  trilateral  discussions  to keep  each  other  informed  of  activities  in  respective jurisdictions.

In  March 2015, Health  Canada  hosted  3  nanotechnology knowledge  transfer sessions  targeting Canadian  government  research  and  regulatory  communities  working  in  nanotechnology.  These  sessions were  an  opportunity  to  share  information  and perspectives  on  the  current  state  of  science supporting  the regulatory  oversight  of  nanomaterials with  Government.  Presenters  provided  detailed  outputs  from  the OECD WPMN including: updates on OECD test methods and guidance documents; overviews of physical-chemical properties, as well as their relevance to toxicological testing and risk assessment; ecotoxicity and fate   test   methods;   human   health   risk   assessment   and   alternative   testing   strategies;   and exposure measurement  and  mitigation.  Guest  speakers  included  Dr  Richard  C.  Pleus  Managing  Director  and  Director of Intertox, Inc and Dr. Vladimir Murashov Special Assistant on Nanotechnology to the Director of National Institute for Occupational Safety and Health (NIOSH).

On   March   4-5, 2015, Industry   Canada   and   NanoCanada co-sponsored  “Commercializing Nanotechnology  in  Canada”,  a  national  workshop  that brought  together  representatives  from  industry, academia and government to better align Canada’s efforts in nanotechnology.  This workshop was the first of  its  kind  in  Canada. It  also  marked  the  official  launch  of  NanoCanada (http://nanocanada.com/),  a national  initiative  that  is  bringing  together stakeholders  from  across  Canada  to  bridge  the  innovation  gap and stimulates emerging technology solutions.

It’s nice to get an update about what’s going on. Despite the fact this report was published in 2016 the future tense is used in many of the verbs depicting actions long since accomplished. Maybe this was a cut-and-paste job?

Moving on, I note the mention of the Canada-led,  ISO  standards project, ISO/DTR  19716 Nanotechnologies — Characterization  of cellulose  nanocrystals (CNC). For those not familiar with CNC, the Canadian government has invested hugely in this material derived mainly from trees, in Canada. Other countries and jurisdictions have researched nanocellulose derived from carrots, bananas, pineapples, etc.

Finally, it was interesting to find out about the existence of  NanoCanada. In looking up the Contact Us page, I noticed Marie D’Iorio’s name. D’Iorio, as far as I’m aware, is still the Executive Director for Canada’s National Institute of Nanotechnology (NINT) or here (one of the National Research Council of Canada’s institutes). I have tried many times to interview someone from the NINT (Nils Petersen, the first NINT ED and Martha Piper, a member of the advisory board) and more recently D’Iorio herself only to be be met with a resounding silence. However, there’s a new government in place, so I will try again to find out more about the NINT, and, this time, NanoCanada.

Ingesting nano silver: a double-blind study

American Biotech Labs (ABL) has released publicity about an intriguing study on ingesting nano silver. From the Apr. 23, 2013 news item on Nanowerk,

The study included 3-, 7-, and 14-day exposures to American Biotech Labs 10-ppm (15 ml/day) silver solution in a double-blind, placebo controlled, cross-over phase design. Healthy volunteer subjects (36, 12 per each time-exposure), underwent complete metabolic, blood and platelet count, urinalysis tests, sputum hyperresponsiveness and inflammation evaluation, physical examinations, vital sign measurements, and magnetic resonance imaging of the chest and abdomen at baseline and at the end of each phase.

… Keith Moeller, A Managing Director at ABL. “… As a prelim to the study, I volunteered to be checked for silver deposition in my body, after 15+ years of almost daily usage as a supplement to help boost my immune system. No silver residue was found anywhere in my system. We are always working hard to gain knowledge about silver. Because of this, we have now amassed a library of more than 300 major reports, studies and test series, all completed on our nano-silver technology by more than 60 different universities, government/military labs, and private institutions.”

In conclusion the report stated, “The In-vivo oral exposure of a commercial 10-ppm silver nano-particle solution over 3-, 7-, and 14-day exposures does not exhibit clinically important changes in metabolic, hematologic, urine, vital sign changes, physical findings or imaging changes visualized by MRI.” …

Oddly, I cannot find where this study was published nor does the news release, which originated the news item, appear on the company website (as of 4 pm PDT April 23, 2013).

As for the study itself, which researchers ran the study? Was a third party contracted to run it? How did they ensure the study was double-blind? I gather this was not a randomized study.

They state specifically there were no urine changes. If the subjects are eliminating the silver, shouldn’t they be able to see that in the urine? If the silver accumulates in the body, how much is too much? Might it not take longer than 14 days to reach a toxic or dangerous stage?

Moeller’s personal endorsement is not really convincing as one assumes that as managing director of the company he has much to gain by encouraging people to ingest nano silver (ABL sells it as a health supplement). The same holds true regarding this study, which seems to have been run by the company itself.

As it stands, the study seems a bit sketchy but hopefully more details will emerge.

Canada-US Regulatory Cooperation Council’s Nanotechnology Work Plan

Thanks for Lynn L. Bergeson for her Dec. 1, 2012 posting on the Nanotechnology Now website for the information about a Nov. 28, 2012 webinar that was held to discuss a Nanotechnology Work Plan developed by the joint Canada-US Regulatory Cooperation Council (or sometimes it’s called the US-Canada Regulatory Cooperation Council),

The RCC requested that industry provide more information on the commercial distribution of nanomaterials, as well as more transparency by claiming confidentiality of only that information absolutely critical to market advantage.

To compare risk assessment and risk management practices to highlight and identify best practices, data gaps, and differences between the two jurisdictions, the RCC sought nominations of a nanomaterial substance for a case study. Four nanomaterial substances were nominated: multiwall carbon nanotubes, nanocrystalline cellulose, nano silver, and titanium dioxide. The RCC has selected multiwall carbon nanotubes for the case study. The RCC intends to hold in March 2013 a workshop in Washington, D.C., to discuss information collected to date and approaches moving forward. In spring 2013, the RCC will hold one or two conference calls or webinars to discuss information gathered between countries and the path forward. Finally, in fall 2013, the RCC expects to hold a stakeholder consultation/workshop on results to date.

Here’s some background on the RCC. First announced in February 2011, the RCC had its first ‘stakeholder’ session (attended by approximately 240)  in January 2012 in Washington, DC. where a series of initiatives, including nanotechnology, were discussed (from the US International Trade Administration RCC Stakeholder Outreach webpage),

Agriculture and Food, Session A

  • Perimeter approach to plant protection

Agriculture and Food, Session B

  • Crop protection products

Agriculture and Food, Session C

  • Meat/poultry – equivalency
  • Meat/poultry – certification requirements
  • Meat cut nomenclature

Agriculture and Food, Session D

  • Veterinary drugs
  • Zoning for foreign animal disease

Agriculture and Food, Session E

  • Financial protection to produce sellers

Agriculture and Food, Session F

  • Food safety – common approach
  • Food safety – testing

Road Transport – Motor Vehicles

  • Existing motor vehicle safety standards
  • New motor vehicle safety standards

Air Transport

  • Unmanned aircraft


  • Intelligent Transportation Systems


  • Dangerous goods means of transportation

Marine Transport

  • Safety and security framework & arrangement for the St. Lawrence Seaway & Great Lakes System
  • Marine transportation security regulations
  • Recreational boat manufacturing standards
  • Standard for lifejackets

Rail Transport

  • Locomotive Emissions
  • Rail Safety Standards


  • Emission standards for light-duty vehicles

Personal Care Products & Pharmaceuticals

  • Electronic submission gateway
  • Over-the-counter products – common monographs
  • Good manufacturing practices

Occupational Safety Issues

  • Classification & labelling of workplace hazardous chemicals


  • Nanotechnology

Led jointly by senior officials from Canada and the United States, the purpose of the various technical review sessions was to seek expert advice and technical input from the approximately 240 stakeholders in attendance.

Since the Jan. 2012 meeting, a Nanotechnology Work Plan has been developed and that’s what was recently discussed at the Nov. 28, 2012 webinar. I did find more on a Canadian government website, Canada’s Economic Action Plan Nanotechnology Work Plan webpage,

Nanotechnology Work Plan

 Canada Leads: Karen Dodds, Assistant Deputy Minister, Science and Technology Branch, Environment Canada (EC)

Hilary Geller, Assistant Deputy Minister, Healthy Environments and Consumer Safety Branch, Health Canada (HC)

U.S. Lead: Margaret Malanoski, Office of Information and Regulatory Affairs, Office of Management and Budget

Deliverable Outcome: Share information and develop common approaches, to the extent possible, on foundational regulatory elements, including criteria for determining characteristics of concern/no concern, information gathering, approaches to risk assessment and management, etc. Develop joint initiatives to align regulatory approaches in specific areas such that consistency exists for consumers and industry in Canada and the US.

Principles: Identification of common principles for the regulation of nanomaterials to help ensure consistency for industry and consumers in both countries

3-6 months:

Canada provides initial feedback on US “Policy Principles for the US Decision-Making Concerning Regulation and Oversight of Applications of Nanotechnology and Nanomaterials”.

6-12 months:

Countries complete an initial draft of shared principles for the regulation of nanomaterials.

12-18 months:

Update of draft principles informed from on-going stakeholder and expert consultations.

18th month:

Stakeholder consultation / workshop on results to date and future ongoing engagement.

Beyond 18 months:

Countries complete final draft of shared principles for the regulation of nanomaterials.

Workplan for Industrial Nanomaterials

Priority-Setting: Identify common criteria for determining characteristics of industrial nanomaterials of concern/no-concern

1-3 months:

  1. Define and finalize workplan (1st month)
  2. Develop mechanisms for stakeholder outreach and engagement (1st month)
  3. Conference call with relevant stakeholders to share and discuss workplan and call for Industry to volunteer nanomaterials for joint CAN/US review

3-6 months:

Share available scientific evidence regarding characteristics of industrial nanomaterials including that obtained from existing international fora (e.g. OECD Working Party on Manufactured Nanomaterials [Canada is a lead in the OECD Working Party on Manufactured Nanomaterials]).

8th month:

Stakeholder workshop to discuss information collected to date and approaches moving forward.

6-12 months:

Initiate an analysis of characteristics of select nanomaterials: similarities, differences, reasons for them.

Initiate discussions on approaches to consider for common definitions and terminology.

12th month:

Second conference call with relevant stakeholders to discuss non-CBI information gathered between the Countries and to discuss path forward in terms of development of reports and analyses.

12-18 months:

Develop draft criteria for determining characteristics of industrial nanomaterials of concern/no-concern.

15th month:

Third conference call with relevant stakeholders to discuss progress and to prepare for the upcoming stakeholder consultation/workshop.

Here’s information for the leads should you feel compelled to make contact,


(Lead) Karen Dodds, Assistant Deputy Minister, Science and Technology, Environment Canada (karen.dodds@ec.gc.ca; ph. 613- 819-934-6851)

Hilary Geller, Assistant Deputy Minister, Healthy Environments and Consumer Safety Branch (hilary.geller@hc-sc.gc.ca; ph. 613-946-6701)

United States

(Lead) Margaret Malanoski, Office of Management and Budget (Margaret_A._Malanoski@omb.eop.gov)

I gather that the ‘stakeholders’ are business people, researchers, and policy analysts/makers as there doesn’t seem to be any mechanism for public consultation or education, for that matter.

Nanosilver history

According to Empa researchers, Bernd Nowack and Harald Krug, together with Murray Heights of the company HeiQ, silver at the nanoscale has a long history. From the Jan. 31,2011 news item on physorg.com,

Nanosilver is not a new discovery by nanotechnologists — it has been used in various products for over a hundred years, as is shown by a new Empa study. The antimicrobial effects of minute silver particles, which were then known as “colloidal silver,” were known from the earliest days of its use.

Their paper showing that nanosilver is not a 21st century discovery is being published in Environmental Science & Technology. From the news item,

Silver particles with diameters of seven to nine nm were mentioned as early as 1889. They were used in medications or as biocides to prevent the growth of bacteria on surfaces, for example in antibacterial water filters or in algaecides for swimming pools.

The nanoparticles were known as “colloidal silver” in those days, but what was meant was the same then as now – extremely small particles of silver. The only new aspect is the use today of the prefix “nano”. “However,” according to Bernd Nowack, “nano does not mean something new, and nor does it mean something that is harmful.” When “colloidal silver” became available on the market in large quantities in the 1920s it was the topic of numerous studies and subject to appropriate regulation by the authorities. [emphasis mine]

This suggests that there has been sufficient research on what we now call nano silver and its impact on the environment and on health. By contrast, the California Department of Toxic Substances Control (DTSC) had this to say in its recent call for information about analytical test methods for nanomaterials (from the Dec. 27, 2010 news item on Nanowerk),

Nano Silver

Nano silver is used increasingly in many consumer products. These include food contact materials (storage containers, cups, bowls and cutting boards), children’s toys and infant products, disinfectants, cosmetics, cleaning agents and machines, textiles, athletic apparel, dyes/paints, varnishes, polymers, and in medical products and applications. Given these diverse applications, nano silver is likely entering the environment. Several scientific studies describe potential adverse effects of nano silver on publicly owned treatment works (wastewater collection, treatment, and disposal systems).

Silver has been known historically as a potent antibacterial, antifungal, and antiviral agent. In recent years, silver is used as a biocide in solution, suspension, and in nano-particulate form. The strong antimicrobial activity is a major reason for the development of products that contain nano silver. Nano silver may also have applications in agricultural, vector, and urban pest control. However, little or no information about detecting and measuring the effect of nano silver in the environment exists. Recent published papers point out difficulties in quantifying the existence of nano particles in environmental and biological contexts, which presents challenges in estimating and assessing the hazards and risks of nano silver. [emphasis mine]

Nowack, one of the Empa researchers, provides evidence for his position in a commentary that was previously published in the journal Science (from the news item),

A commentary by Bernd Nowack in the scientific journal Science discusses the implications of the newest studies on nanosilver in sewage treatment plants. More than 90% remains bound in the sewage sludge in the form of silver sulfide, a substance which is extremely insoluble and orders of magnitude less poisonous than free silver ions. [emphasis mine] It apparently does not matter what the original form of the silver in the wastewater was, whether as metallic nanoparticles, as silver ions in solution or as precipitated insoluble silver salts.

“As far as the environmental effects are concerned, it seems that nanosilver in consumer goods is no different than other forms of silver and represents only a minor problem for eco-systems,” says Nowack. What is still to be clarified, however, is in what form the unbound silver is present in the treated water released from sewage works, and what happens to the silver sulfide in natural waters. Is this stable and unreactive or is it transformed into other forms of silver? [emphasis mine]

The two approaches are not directly contradictory but I do find the totality confusing. Which challenges about the hazards and risks of nano silver are the folks in California referring to? It seems they’re not familiar with the older research cited by Nowack or perhaps they know something Nowack and his colleagues do not. Meanwhile, Nowack’s Science commentary is reassuring but whoever wrote the news item was careful to point out that there is still some important work to be done before declaring nano silver to be a ‘safe’ substance.

I posted about the DTSC call for information, Feb. 7, 2011.

California’s call for information about nanomaterials

A little late but better than never, the US state of California has issued a call for information focused on analytical test methods, i.e., lab procedures for testing, nano silver, nano zero valent iron, nano titanium dioxide, nano zinc oxide, nano cerium oxide, and quantum dots. The deadline for a response is Dec. 21, 2011, one year from the date of the request. From the Dec. 27, 2010 news item on Nanowerk,

DTSC [Department of Toxic Substances Control] has conducted a search of known public sources for analytical test methods for these six nanomaterials. We have compiled our research in this bibliography. DTSC has also contacted and consulted with manufacturers, researchers, environmental laboratory experts, other governments, and stakeholders regarding analytical test methods for these nanomaterials in these matrices. We convened public workshops and symposia on nanotechnology and, in particular, these six nanomaterials.

From our research, consultations, and workshops, we have determined that little or no information on analytical test methods for these nanomaterials in the human body or the environment now exists. To better understand the behavior, fate and transport of the se six nanomaterials, appropriate analytical test methods are needed for manufacturers, for contract and reference laboratories, and for regulatory agencies.

You can get more information about the call from the DTSC site including a list of companies that received the ‘call for information’ letter.