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EC number: 231-131-3
CAS number: 7440-22-4
See CSR Annex 4 - PNEC Summary Report
and chronic aquatic toxicity data are available for a range of different
freshwater and marine species. For silver and silver compounds, the
acute ecotoxicity reference value (ERV) is 0.22 µg Ag/L and the chronic
ERV is 0.1 µg Ag/L.
line with the risk assessment/classification approach adopted for other
metals and inorganic metal compounds (ECHA 2013), ecotoxicity data are
reported in terms of the concentration of dissolved silver ions from
soluble inorganic silver species. Predominantly, these are studies that
used silver nitrate (AgNO3) as the source of dissolved silver ions.
Silver nitrate is considered to be the form of silver with the greatest
toxicity as it dissociates rapidly and completely in aqueous solution.
Where data for silver nitrate was not available, data derived from other
inorganic salts (e.g. silver chloride) were used, but only after the
exposure conditions were determined to be acceptable (e.g. testing was
conducted within the limits of solubility and the Ag+ ion was likely to
be the dominant dissolved species).
complete base set of acute ecotoxicity studies is available for soluble
inorganic silver species, comprising numerous studies for fish,
invertebrates and algae. The lowest reliable acute value is an EC50 of
0.22 µg Ag/L for the invertebrateDaphnia magna(Bianchini et
complete chronic data set is also available for soluble inorganic silver
species, with chronic ecotoxicity data available for various species of
fish, invertebrates and algae. The lowest reliable chronic value is an
EC10 of 0.1 µg Ag/L for the algaePseudokirchneriella
2017). Additional chronic toxicity data of similar sensitivity are also
available for thethe
blue-green algae Nostoc muscorum (Rai et al. 1990),Brown
TroutSalmo trutta(217 day EC10 of 0.19 µg Ag/L) andOncorhynchus
mykiss(196 day EC10 of 0.17 µg Ag/L) obtained from Davies et al.
on current guidance (ECHA 2013), soluble silver is classified as R50/53
under the DSD, with specific concentration limits of Cn ≥0.025% for
R50-53, ≥0.0025% Cn <0.025% for R51-53, and ≥0.00025% Cn <0.0025% for
R52-53. Soluble silver is also classified as Acute 1 and Chronic 1 under
the CLP regulations and subject to an acute M factor of 1000 and a
chronic M factor of 100.
and coated nanomaterials (as per EU definition – median particle size
precautionary classification for silver and silver-based (coated)
nanomaterials has been read across from data for soluble silver (see
below). Similarly, appropriate M factors have been based on read across
from soluble silver.
classification strategy for poorly soluble silver substances has been
based on ECHA guidance (ECHA 2013). This guidance describes how to
determine the classification and appropriate M factors for poorly
soluble substances, such as elemental silver powder and massive silver,
from acute and chronic ERV and the results of T/D tests (Annex IV:
Metals and Inorganic Metal Compounds). Acute and chronic classifications
have been undertaken individually.
The T/D-data generated for nanosilver for the silver substance
evaluation under REACH should not be used for classification purposes.
On specific request of the Evaluating MS this T/D study was performed in
non-standard modified daphnia and algae media (with chloride salts
replaced by nitrate salts to maximise the concentration of ionic Ag).
These conditions are deviating from the standard medium described in
OECD Test Guideline 29. The OECD 29 Test Guideline was developed for
hazard classification purposes, and therefore any deviation from the
guideline (like changes in the medium composition that may affect the
solubility and bioavailability of the test compound) makes the results
not useable for hazard assessment.
In absence of reliable T/D data (generated according to OECD Testing
Guideline 29) for nanosilver, the environmental classification of
uncoated and coated nanomaterials has therefore been directly read
across from soluble forms of silver. Silver and silver-based
nanomaterials would therefore be classified as per soluble silver
substances: Acute and Chronic Category 1.
M factors have also been read across from soluble forms of silver. This
read-across results in acute and chronic M factors of 1000 and 100,
respectively, for uncoated and coated nanomaterials.
the weight of evidence available suggests that the ecotoxicity of
uncoated and coated nanomaterials is lower than soluble silver on an
equivalent mass basis (see read-across matrix for environmental
endpoints), read across from soluble silver in this case is expected to
result in a precautionary classification and M-factors for nanosilver.
as the dissolution rates of uncoated and coated nanomaterials are
expected to be variable dependent on morphology, particle size, particle
size distribution and coating, this approach encompasses the range of
likely properties of nano silver and is consistent with the read across
rationale applied to uncoated and coated nanomaterials for environmental
the purposes of this read-across, silver-based (coated) nanomaterials
are considered to be those that are primarily based on elemental silver
and fulfil the criteria of the Commission Recommendation for the
definition of nanomaterials, but which also comprise a surface
functionalisation/coating/capping. The scope of the read-across from
soluble silver to elemental silver and elemental silver-based (coated)
nanomaterials for classification is identical to the scope of the
environmental assessment of silver and silver-based (coated)
nanomaterials in the REACH chemical safety assessment (CSA), i.e. the
read-across is only considered to be applicable where applied to
elemental silver nanomaterials or elemental silver-based nanomaterials
with additional surface functionalisation/coating/capping that is
demonstrated to be non-toxic, biodegradable, “passive” and applied
primarily to increase the stability of nanomaterial dispersions in
aqueous or non-aqueous solutions (i.e. to prevent aggregation or
agglomeration) through steric, electrostatic or comparable mechanism.
Surface functionalistion/coating/capping that are specifically designed
to interact with biological receptors or which have hazardous properties
in their own right (e.g. meet the criteria for SVHC) would not be
compatible with this read-across approach for classification. Equally,
multi-metal nanomaterials incorporating elemental silver are outside of
the scope of this read-across.
(2013) Guidance on the Application of the CLP Criteria. Guidance to
Regulation (EC) No 1272/2008 on classification, labelling and packaging
(CLP) of substances and mixtures. Version 4.0, November 2013.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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