Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 231-131-3
CAS number: 7440-22-4
In a non-standard batch extant respirometric assay the NOEC for
inhibition of autotrophic nitrification by AgNO3 was determined to be
0.025 mg Ag/L.
Read across from ionic silver
Plus supporting published data from several studies included in the
REACH dossier as Endpoint Study Records with various sizes of
nanoparticles and coating types, reporting comparative effects of silver
and nanosilver on microorganisms relevant to wastewater treatment
of available data for uncoated and coated nanomaterials
Reliable and relevant data on the effects of silver and
silver-based (coated) nanomaterials are available from 15 studies.
These studies describe the effects of nanosilver on microorganisms
relevant to wastewater treatment (i.e. cultures of nitrifying bacteria
or activated sludge populations) or directly on wastewater treatment
processes (i.e. effects on nitrification rates or phosphorus removal
efficiency). Some studies report the results of a comparative
assessment between the effects of nano silver and ionic silver.
Additional studies reporting the effects on nanosilver on yeast (Saccharomyces
cerevisiae), Escherichia coli and naturally occurring
assemblages/communities of microorganisms in the environment (i.e.
rivers, lakes and wetlands) were identified in the literature search,
but after initial assessment were not considered to be relevant to the
REACH endpoint and are not considered further.
The most sensitive effects for nanosilver on microorganisms are
reported in a series of five associated studies from the University of
Missouri by Choi and Hu (2008 and 2009), Choi et al. (2008 and 2009)
and Liang et al. (2010). These studies report the results of a series
of experiments investigating the potential impacts of nanosilver on
nitrification and organic matter removal during simulated wastewater
treatment, including a comparison with the effects of ionic silver.
The ionic silver data presented in Choi and Hu (2008) was the key data
identified for the toxicity to aquatic microorganism endpoint in the
REACH CSR for silver. Their studies consistently report that
nanosilver is more toxic (by approximately 50%) than ionic silver when
assessed on an equivalent mass basis. However, many of the studies
used a single exposure concentration (Choi et al. 2009, Choi and Hu
2009, Liang et al. 2010), which makes robust characterisation of
relative toxicity difficult. Where multiple concentrations were used
to characterise the dose-response relationship (Choi and Hu 2008, Choi
et al. 2008), these exposures also indicated that nanosilver was more
toxic than ionic silver to nitrifying microorganisms. However, at the
lowest portion of the dose-response (i.e. NOEC/LOEC values) it was not
possible to distinguish between the relative toxicity of nanosilver
and ionic silver. As such, the NOEC value used to derive the STP PNEC
for the REACH registration of silver based on ionic silver is also the
NOEC for nanosilver. Jeong et al. (2012) also investigated the effects
of exposure to nanosilver on nitrification, reporting that the
inhibition observed in their 12-hour batch testing system was “much
lower” than that observed by Choi and Hu (2008) and Liang et al.
(2010) resulting in a NOEC for nitrification of 0.5 mg/L and
denitrification of 10 mg/L, which they consider could be the
consequence of “different characteristics of activated sludge”. Jeong
et al. (2012) do not report any comparative assessment of nanosilver
and ionic silver.
Other studies (Radniecki et al. 2011, Sheng et al. 2011, Dams et
al. 2011, Wang et al. 2012, Chen et al. 2012) also report the
comparative effects of silver and nanosilver on microorganisms
relevant to wastewater treatment. However, in contrast with the
University of Missouri studies reported above, these all report that
ionic silver is more toxic than nanosilver to aquatic microorganisms.
For example, Chen et al. 2012 report the relative effects of ionic
silver and nanosilver (uncoated, with a particle size of 20-40 nm) on
enhanced biological phosphorus removal (EBPR). No effects on
phosphorus removal were observed in nano silver exposures up to 5
mg/L. However, a NOEC of 0.5 mg/L was reported for ionic silver.
Radniecki et al. (2011) reported that smaller nanoparticles (20
nm) were more toxic than larger nanoparticles in their nitrification
batch assay, which is consistent with the effects observed in Daphnia
reported in section 4.2.4.
There is insufficient data available to make any conclusion on
the influence of coating on the toxicity of nano silver to aquatic
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.
På den här webbplatsen används kakor. Syftet är att optimera din upplevelse av den.
Welcome to the ECHA website. This site is not fully supported in Internet Explorer 7 (and earlier versions). Please upgrade your Internet Explorer to a newer version.
Do not show this message again