Evaluate Determinants of Exposure

  1. Dustiness
  2. Process
  3. Quantity
  4. Frequency and Duration

The European Food Safety Authority established the following table to characterize engineered nanomatierals prior to use in food/feed related applications.  That said, the guidance provided in this table should be of assistance in other applications:

"Parameters for characterisation and identification of ENM"1

Parameter
Requirements
Description
Chemical composition/ identity
Essential
Information on chemical composition of the ENM – including purity, nature of any impurities, coatings or surface moieties, encapsulating materials, processing chemicals, dispersing agents and/or other formulants e.g.
stabilisers.
Particle size (Primary/
Secondary)
Essential
(two methods, one being electron microscopy)
Information on primary particle size, size range and number size distribution (indicating batch to batch variation – if any). The same information would be needed for secondary particles (e.g. agglomerates and aggregates) if present. .
Physical form and morphology
Essential
Information on the physical form and crystalline phase/shape. The information should indicate whether the ENM is present in a particle-, tube-, rod-/shape, crystal or amorphous form, and whether it is in free particulate form or in an agglomerated/aggregated state as well as whether the preparation is in the form of a powder, solution, suspension or dispersion.
Particle and mass concentration
Essential for dispersions and dry powders
Information on concentration in terms of particle number and particle mass per volume when in dispersion and per mass when as dry powder.
Specific surface area
Essential for
dry powders
Information on specific surface area of the ENM.
Surface chemistry
Essential (for ENM with surface modifications)
Information on ENM surface – including any chemical/ biochemical modifications that could modify the surface reactivity, or add a new functionality.
Surface charge
Essential
Information on zeta potential of the ENM.
Redox potential
Essential for inorganic
ENMs
Information on redox potential. Conditions under which redox potential was measured need to be documented.
Solubility and partition propertiesa
Essential
Information on solubility of the ENM in relevant solvents and their partitioning between aqueous and organic phase (e.g. as log Kow if appropriate).
pH
Essential for liquid
dispersions
pH of aqueous suspension.
Viscosity
Essential for liquid
dispersions
Information on viscosity of liquid dispersions.
Density and pour density
Essential for granular materials
Information on density/porosity of unformulated ENM and pour density.
Dustiness
Essential for
dry powders
Information on dustiness of powder products – such as spices, creamers and soup powders.
Chemical reactivity/catalytic activityb
Essential
Information on relevant chemical reactivity or catalytic activity of the ENM and of any surface coating of the ENM.
Photocatalytic activity
Essential for photocatalytic materials
Information on photocatalytic activity of relevant materials used in food packaging, coatings, and printing inks and internal reactions.
 

a)        Dispersion, solution, dissolved: An insoluble ENM introduced to a liquid form a ‘dispersion’ where the liquid and the ENM coexist. In a true solution the ENM is dissolved (and thus not present) (see OECD ENV/JM/MONO(2010)25)
b)       If an ENM has catalytic properties, it may catalyse a redox or other reaction that may perpetuate resulting in a much larger biological response even with small amounts of the catalytically active ENM. Thus, compared to a conventional biochemical reaction that uses up the substrate, ENM reaction centres may perpetuate catalytic reactions.


 

  

Created by admin. Last Modification: Friday 27 of May, 2011 18:08:57 EDT by GoodNanoGuide526 points .

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