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Dissemination reports
 

Dissemination reports from Nanosafe2 project are designed to highlight and present in a simplified way the main results obtained in the studies carried out during this project. These reports mainly deal with one question which is of general concern for whom is interested by the safe production and use of nanomaterials.

 Are conventional protective devices such as fibrous filter media, respirator cartridges, protective clothing and gloves also efficient for nanoaerosols?

Long before the final conclusions of toxicology research studies on the potential hazard of nanomaterials, it is today necessary to apply the principle of precaution by implementing among other, efficient personal protections against engineered nanoparticles. In this study, carried out in the frame of the Nanosafe2 project, different conventional individual protection devices well-qualified for micron size particles such as fibrous filters, repirator cartridges, protective clothing and gloves were tested with graphite nanoparticles ranging from 10 to 150 nm.

Main results

    • Fibrous filters are even more efficient for nanoparticles!
    • HEPA filters, respirator cartridges and mask made with fibrous filters are even more efficient for nanoparticles.
    • Non woven fabrics seem much more efficient (air-tight materials) against nanoparticle penetration.
    • Warning: Nanoparticles may penetrate through commercially available gloves! Thus use at least 2 layers of gloves.
Download this report: DR1_s.pdf

 What about explosivity and flammability of nanopowders?

One of the main questions asked about nanopowders, when it comes to explosivity and flammability, is: Do nanopowders behave like other powders and, as such, can they more readily ignite and explode? During this study, carried out in the frame of the European Nanosafe2 project, safety parameters of nanopowders and their associated techniques and practices have been characterised for a representative set of particles of industrial relevance.

Main results

  • New confined stainless steel Hartmann tube and falling hammer equipment help bring experiments to a higher degree of safety and efficiency
  • Lesson: Studied carbon nanotubes exhibit explosion severities and sensitivities of the same order as those found for various coals, food flours and other nanostructured carbon blacks.
  • Lesson: For metallic aluminum nanopowders, the small oxyde layer wrapping passivated nanoparticles may make them less explosible than micropowders.
  • Lesson: Nanopowders which tend to agglomerate show explosion violence characteristics of the same order as those observed with micropowders of the same substance.
  • Lesson: Onset temperature of carbon materials strongly depends on the specific surface area of those materials.
  • Warning: For aluminum, combustion mechanisms of nanosized particles are different from those observed with microsized particles. This may lead to potential problems of large scale industrial storage of such particles.
    Advice: Specific prevention and protection measures should then be taken.
Download this report: DR2_s.pdf

 Is it possible to easily measure the engineered nanoparticles at workplaces?

Nanoaerosols are composed of nanoparticles which may originate from different sources. Already about 10 000 natural nanoparticles per cubic centimetre of air are present even in the “pure” atmosphere of our mountains. This very high level may be enhanced by anthropogenic activities: unwanted production of nanoparticles in combustion processes called Incidental particles and Engineered particles produced intentionally in laboratories and in the industry. The detection sensitivity for engineered nanoparticles is limited by the high background noise due to Natural and Incidental nanoparticles.

Main results

Background noise

The detection sensitivity of engineered nanoparticles is handicapped by the very high and fluctuating levels of already existing particles. Therefore the detection limit of engineered particles in conventional environments is in the 100000 – 1000000 particles/mL range!

It is easier to detect engineered nanoparticles in controlled environments (clean room, portable filtering canopy, etc.)

Measurement principles

It is necessary to standardize the chosen measurement method according to the nanoparticle types to be measured.

It is often difficult to compare measurements performed with equipmentusing different principles.

Easy-to-use equipments

A large variety of equipment can be already used to measure the nanoaerosols at workplaces.

Their use is quite simple, but the interpretation of the results requires a rigorous analysis to quantify the engineered nanoparticles. It is often necessary to take into account the background noise, the specific response of the measurement tool to the engineered nanoparticles of interest, the agglomeration kinetics, etc.

Monitoring and Sampling

Unfortunately no equipment is commercially available today for long term monitoring. Characteristics and performances of the future monitoring devices are being defined.

It is possible to sample nanoparticles with an electrically conductive pipe of 20 m as long as the flow rate is greater than 10L/min. 

Download this report: DR3_s.pdf

 How to estimate nanoaerosol explosion risk?

To estimate an accidental risk level, four factors have to be evaluated:

  • Nanopowder Safety Parameter
  • Process factors
  • Probability of occurrence of accident
  • Vulnerability of the target, worker or environment

Main results

  • To evaluate nanopowder safety characteristics, morphologic, surface and bulk properties as well as their potential to disperse in their environment have to be characterized.
  • Most nanopowders can display high reactivity characteristics that can lead to fire or explosion accidents. Specific tools and protocols are necessary to assess these parameters.
  • Environmental and process factors (flow velocities, materials fluxes and inventories, Pressures , Temperatures and concentrations) are key elements to consider in the risk assessment
  • Once the risk evaluated, one can propose various types of safety barriers to reduce the risk:
    • A Prevention barrier to reduce the probability of occurrence of an accident.
    • A Mitigation barrier to reduce the effects of process parameters or propose product substitution or severity attenuation.
    • A Protection barrier, such as protection equipments, confinement technologies or venting system, to protect the worker or the environment.
Download this report: DR4_s.pdf

 What is nanotoxicology?

How to estimate the potential hazard related to nanoparticles?

Main results

  • The study of toxic effects of nanomaterials is still under development and many questions are unanswered.
  • Nanoproducts' number grows very rapidly. It is therefore urgent to assess for each of them the likely routes of exposure and the potential toxicity.
  • More research is needed to better understand specific particle properties and other factors that influence their toxicity.
  • New toxicity methods have to be developed and validated. Potential impact on human health and environment should be tested over the entire life-span of the material.
Download this report: DR5_s.pdf

 First results for safe procedures for handling nanoparticles.

Generally it is of common knowledge that risk assessment in using hazardous or potentionally hazardous chemical substances, either the exposition itself or the risk of those materials has to be minimised. The potential danger for someone can be derived from the basic fact, that direct contact with a potentially harmful substance has to be avoided.

Currently, it is still quite unclear, which nanoparticulated material in which state and from reveals which type of danger. It is also unclear, if current measurement and classification of conventional materials, such as critical mass concentration at working places can be applied for the industrial usage of nanoparticles at all.

Main results

  • Avoid free flowing nanoparticles in air Eliminate ignition sources.
  • Extended personal protection equipments are required during (un)loading processes. EX-Zone should be defined.
  • Vacuum cleaning or variable speed fan with appropriate nanoparticle collection appear to be efficient cleaning method.
  • In terms of waste disposal labelling and packaging are carried out according to national and international regulations.

Final suggestions

  • Use of nanoparticles in dispersion or in an agglomerated state.
  • If this cannot be done, secure process containment is a must.
  • Inert processes, if applicable.
  • Efficient exhaust systems with particles filtration (e.g. HEPA filter H14).Personal protection equipment (Nitrile glove (2 pairs recommended), Mask (FFP3 or powered respirators incorporating helmets), Suits and safety shoes).
Download this report: DR6_s.pdf

 Do current regulations apply to engineered nanomaterials?
Standards – Why standardisation and standards are important?

Regulations:

There is no specific regulation for any nanomaterials. However, national and European regulations are applicable to nanomaterials. The main European health and safety regulations for the protection of workers include:

·           Directive 67/548 – 1999/45: Classification, packaging and labelling of Dangerous substances.

·           Directive 98/24/EC on the protection of the health and safety of workers from the risks related to chemical agents at work (fourteenth Directive within the meaning of Article 16(1) of Directive 89/391/EEC).

Health, safety and environmental protection aspects associated with nanomaterials are in principle covered to different levels by current EU regulatory framework.

 

Standards:

Standardisation and standards provide an important mechanism to support both innovation and the application of regulations. A number of national, European and international organisations are developing standards that either focus on or have sections dealing with the protection of human health and the environment from the production and use of chemicals and consumer products, containing nanomaterials.

Main results

  • National and European regulations are applicable to nanomaterials.
  • Element of the precautionary principle exists in different regulatory approaches.
  • Standardisation and standards provide an important mechanism to support both innovation and the application of regulations.
Download this report: DR7_s.pdf

 Laser-Induced Breakdown Spectroscopy (LIBS): A possible tool for on-line monitoring and surveillance of nanoparticle production processes.

Tracking nanoparticles for on-line monitoring of production processes or workplace surveillance requires their identification, the latter being based on one of their intrinsic properties such as elemental composition or shape. However, most of the currently available tools dedicated to nanoparticle metrology do not allow differentiating manufactured nanoparticles from those of background air, thereby rendering targeted nanoparticle detection arduous. Such problem may be addressed by chemically identifying nanoparticles. To achieve this goal, the LIBS (Laser-Induced breakdown Spectroscopy) technique was deemed as a potential candidate.

 

Main results:

LIBS technique presents many advantages for on-line monitoring and workplace surveillance of nanoparticle production processes.

 

A compact LIBS system intended to be operated on-site was designed and put to the test for both purposes:

·   On-line monitoring of a nanoparticle production process.

·   Workplace surveillance.

 

LIBS potentially well suited for on-line monitoring of composite nanoparticle stoichiometry while the production process is being operated:

·   LIBS easily implemented on industrial sites.

·   Additional experiments should consolidate these results.

 

LIBS potentially adapted for workplace surveillance:

·   Direct measurement in the air suitable for leak detection.

·   Collection on a substrate prior to LIBS interrogation more appropriate for chronic risk assessment.

Download this report: DR8_s.pdf

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