nanotechnology in fertilizers and supplementsnanotechnology in fertilizers: safety? from a safety...
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© 2007 Her Majesty the Queen in Right of Canada
(Canadian Food Inspection Agency), all rights reserved. Use without permission is prohibited.
Nanotechnology in
Fertilizers and Supplements
February 21, 2017
Nathalie Decan, Ph.D.
Safety Evaluator, Fertilizer Safety Section
Canadian Food Inspection Agency
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Background/Introduction:
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Health Canada considers any manufactured
substance or product and any component
material, ingredient, device or structure to be
nanomaterial (NM) if:
(1) It is at or within the nanoscale in at least
one external dimension, or has internal or
surface structure at the nanoscale (1-100
nanometers inclusive);
or
(2) It is smaller or larger than the nanoscale
in all dimensions and exhibits one or more
nanoscale properties/phenomena.
Nano?
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Background/Introduction: Why NMs?
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The rapid
expansion of NM
applications and
NM marketplace
presence prompts
the question –
Why NMs?
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Unique characteristics
affecting performance,
quality, safety, and/or
effectiveness of a product.
Chemical, physical and
biological properties that
differ from those of their
macro-scale counterparts.
Potential for: altered toxicity
and behaviour with a largely
unknown impact on
human health and the
environment.
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Background/Introduction: Why NMs?
Their nanoscale size imparts:
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Nanotechnology in Fertilizers and Supplements
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“Fertilizer”: any substance or mixture of substances, containing nitrogen,
phosphorus, potassium or other plant food, manufactured, sold or
represented for use as a plant nutrient.
“Supplement”: any substance or mixture of substances, other than a
fertilizer, that is manufactured, sold or represented for use in the
improvement of physical conditions of soils or to aid plant growth or crop
yields.
The Fertilizers Act defines:
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Nanotechnology in Fertilizers and Supplements
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Includes products that:
(1) consist entirely of NMs
(2) contain NMs as a component
or
(3) otherwise involve the application of nanotechnology.
Nano-fertilizers and supplements:
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Nanotechnology in Fertilizers and Supplements
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Desirable Properties of nano-enabled fertilizers and supplements:
Controlled release
formulations
Solubility and dispersion for
mineral micronutrients
Nutrient uptake
efficiency
Loss rate of fertilizer nutrients
Effective duration of
fertilizer release
Increase resistance to stress and improve crop yield
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Nanotechnology can enable highly controlled nutrient release:
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Nutrient can be encapsulated inside a NM (nanotubes or nanoporous materials)
The nutrient is coated with a thin, protective polymer (NM) film
Nutrients are delivered as particles or emulsions of nanoscale dimension
ON-DEMAND
nutrient delivery that is
synchronized with the
nutritional demand of
the crop
potentially mitigating
nutrient leaching and
promoting
environmental
sustainability of
fertilizer use.
Nanotechnology in Fertilizers and Supplements
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Accepted January 9, 2017
• Urea: rich source of nitrogen and a commonly used fertilizer.
• High solubility of urea molecules is reduced by incorporating it into a matrix of
hydroxyapetite nanoparticles (similar to naturally occurring rock phosphate).
• Demonstrate the potential to maintain crop yields while reducing the urea used
by slowing nitrogen release.
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Nanotechnology in Fertilizers: Safety?
From a safety standpoint, fertilizers and supplements containing NM or
featuring nanotech merit special consideration.
Importantly, we cannot categorically judge all products containing NM
as intrinsically benign or harmful.
Assessment of the characteristics of each finished product and safety for its
intended use (case by case basis) is the currently accepted way forward.
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NM-Containing Product Regulation in Canada
The Pest Control Products Act, the Feeds Act and the Fertilizers Act are
CEPA-Equivalent for the purposes of risk assessment of new substances.
These establish a legal regime for the assessment and management of new
and existing substances (including NMs), and requires importers or
manufacturers of new substances to provide specific information to
government officials so that it can be evaluated for potential effects on
human health and the environment.
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Requirements of the Risk Assessment Process
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• Access to sufficient, good quality, relevant, data
• Scientific expertise in data interpretation
• Independence of the assessors and transparency of the process.
• Clear explanation of the findings along with the rationale and the
areas of uncertainty
Human Health and Environmental Risk Assessment:
i) range of exposure conditions (during manufacture, use and disposal), to
each substance of interest
i) identification of hazard properties
ii) susceptible population groups and uncertainties in the RA
Human Health and Environmental Risk Assessment
(RA)
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Risk Assessment Process: Nanomaterials
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Does a substance in nano form = a higher risk
to human health / environment than the macro-
scale counterparts?
Can hazard data on a substance in other
physico-chemical forms be used for NM
assessments??
Each substance in a new nano-form needs to be considered
individually.
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Given that NMs often exhibit
new or altered
physicochemical
characteristics, it is important
that these properties are
identified and appropriately
addressed during safety
evaluations.
A wide range of physical and
chemical properties should be
evaluated during NM
characterization including
assessment of impurities
present.
Special Considerations for Safety Assessment
NM Characterization:
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Examples of toxicity mechanisms:
Dissolution:
The release of toxic constituents from NMs (e.g., ionic
silver from AgNPs etc)
Surface effects:
Direct effect from physical contact with NMs (e.g.,
interference with important
biomolecules)
NM structure effects:
Inherent properties of the material
NM Trojan horse effects:
The capacity of NMs to act as vectors for the
transport of substances to
sensitive tissues.
Special Considerations for Safety Assessment
Health,
safety and
environment
The Fertilizer Safety Section is developing a comprehensive risk assessment
framework that will enable pre-market safety evaluation of NMs.
This approach is being further validated other Government of Canada
Departments and is in accordance with OECD recommendations.
NM Safety Assessment Preparedness
Diversity
of
disciplines
impacted
Termi-
nology
Coordination
and
harmonization
across
standards
developers and
stakeholders
Measurement
and
characterization
Materials
specifications
Rapid speed of
development
Global
Impact
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Summary
o Fertilizer and supplement manufacturers are beginning to harness
nanotechnology to deliberately manipulate or control particle size in order
to produce specific, unique technical effects in the final product.
o Nano- applications in fertilizers and supplements raises questions about
the safety of the products for their intended use.
Going forward:
We are currently validating of our proposed approach for NM safety
assessment.
We will continuously access research and safety data as it becomes
available, to facilitate ADAPTIVE, case-by-case premarket safety
assessment of NMs in fertilizers and supplements.
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