nanomaterials and definitions - standards australia · 2018. 1. 24. · nanomaterials and...
TRANSCRIPT
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Nanomaterials and Definitions
- A Regulator’s Perspective
Dr Kerry Nugent
Principal Scientist
Existing Chemicals Program
NICNAS
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The regulatory need
A strategy for the regulation of industrial
nanomaterials uses a tiered approach:
Tier 1: identify substances that should be captured
within this strategy
• “working definition”
– substances enter into the regulatory framework
Tier 2: risk assessment
– further definitional refinement
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Distinguishing one chemical from another
• Chemical Identity
– eg name, CAS number
• Need for objective clarity in use of chemical
identity
– Each person using the identity information should
get the same answer
– Legal enforceability
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Nanomaterial identity needs to account
for: • “Sameness”
– Need to identify when two nanomaterials have the
same chemical identity
• Existing Risk Assessment paradigms
– Nanomaterial definitions should not imply need for
nano-specific assessment when the material is
better dealt with by an existing methodology
– Need additional information
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Sameness
• A generic risk assessment covers all materials that
are the same
• For nanomaterials, the boundaries of “sameness”
are not clear
• Potentially enormous number of variables
– Size, aspect ratio, surface morphology, surface
chemistry….
– Toxicological significance????
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Existing Risk Assessment paradigms
• Many classes of chemicals that are currently risk
assessed meet nanoscale definition
– Globular proteins
– Colloidal polymers
– Large molecules
• Nano-specific assessment methodologies likely to
be less appropriate for these materials than
existing methodologies
– eg paint polymers – polymer of low concern
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The NICNAS Working Definition
• … industrial materials intentionally produced,
manufactured or engineered to have unique
properties or specific composition at the
nanoscale, that is a size range typically between
1 nm and 100 nm, and is either a nano-object
(i.e. that is confined in one, two, or three
dimensions at the nanoscale) or is
nanostructured (i.e. having an internal or
surface structure at the nanoscale)”
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Notes to the working definition
• intentionally produced, manufactured or engineered materials are
distinct from accidentally produced materials
• ‘unique properties’ refers to chemical and/or physical properties
that are different because of its nanoscale features as compared to
the same material without nanoscale features, and result in unique
phenomena (e.g. increased strength, chemical reactivity or
conductivity) that enable novel applications.
• aggregates and agglomerates are considered to be nanostructured
substances
• where a material includes 10% or more number of particles that
meet the above definition (size, unique properties, intentionally
produced) NICNAS will consider this to be a nanomaterial.
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Considerations on the working definition
• Chemical identity
– Inherent in the definition
• Objectiveness
– “unique properties” is subjective
• Sameness
– Does not identify “sameness”
• Existing Risk Assessment paradigms
– Taken into account because of “unique properties”
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ISO Definition Elements
• Nanoscale is objective and highly relevant
• Descriptive terms such as nanorod, nanoplate have
relevance for “sameness”
• Nanomaterial as any material with one or more
dimensions in nanoscale not a good regulatory
definition
– “bycatch” (existing paradigms)
– Does not address polydisperse materials