Environmental health hazard profile

• Author: Clemm, Christan; Löw, Clara; Baron, Yifaat; Moch, Katja; Möller, Martin; Köhler, Andreas R; Gensch, Carl-Otto; Deubzer, Otmar
• Pages: 30-32

RoHS Annex II Dossier, final

Diantimony trioxide (flame retardant)

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4 ENVIRONMENTAL HEALTH HAZARD PROFILE

The Canadian Ministries of the Environment and of Health conducted a screening assessment of

diantimony trioxide in 2010. For environmental effects, the assessment is mainly based on

information on the acute and chronic toxicity of dissolved antimony to a variety of aquatic, soil and

sediment organisms compiled in the EU RAR (2008).

As for the environmental fate, the Canadian Ministries of the Environment and of Health59 summarize

that diantimony trioxide has some (though limited) solubility in water and will therefore dissolve in

contact with moisture once in these ecosystems and yield a variety of dissolved antimony species,

depending on the environmental conditions. Given its negligible vapour pressure and limited water

solubility, antimony trioxide will tend to remain in soil rather than migrate into other environmental

media, such as air or water.60

The transformation of diantimony trioxide in the different environmental compartments is rather

complex as described in the EU RAR (2008)61. The appearance of different binding/speciation forms

and oxidation states of antinomy depends on the pH, the presence of other metal ions or on oxic

versus anoxic systems for sediments and soil.

Regarding potential PBT properties, the European approach as laid down in REACH Annex XIII

defines that the PBT and vPvB criteria only apply to organic substances, including organo-metals.

However, the Canadian Ministries of the Environment and of Health62 consider the substance

diantimony trioxide as being persistent because the trivalent antimony ions that are released into

solution when it dissolves cannot be irreversibly degraded. Depending upon ambient conditions, e.g.

pH, trivalent antimony can be oxidised to pentavalent antimony. This transformation is typically

reversible. Therefore, the Canadian Ministers of the Environment and of Health63 conclude that

antimony trioxide meets the persistence criteria for all media (i.e., air, water, soil and sediment).

To conclude, potential releases of ATO from EEE manufacturing and use would dissolve, though

limited, in the environment and would be part of dissolved antimony species found in the

environment.

Endpoints of concern

The Canadian Ministries of the Environment and of Health64 conclude that the data indicate that

soluble forms of antimony generally have a moderate potential to cause harm to aquatic, soil and

sediment organisms.

There are companies notifying self-classifications, so called notifiers, that classify diantimony trioxide

for being hazardous to the aquatic environment (Aquatic Acute 3 - H412, Harmful to aquatic life with

long lasting effect). It is noted that self-classification has a lower certainty than a classification of a

joint submission.

59 Op. cit. Environment Canada, Health Canada (2010)

60 Environment Canada, Health Canada (2010): Screening Assessment for the Challenge Antimony trioxide (Antimony

oxide) Chemical Abstracts Service Registry Number 1309-64-4; September 2010; https://www.ec.gc.ca/ese-

ees/9889ABB5-3396-435B-8428-F270074EA2A7/batch9_1309-64-4_en.pdf, last viewed 19.04.2018

61 Op. cit. EU RAR European Union Risk Assessment Report (2008): Diantimony trioxide, November 2008

62 Op. cit. Environment Canada, Health Canada (2010)

63 Op. cit. Environment Canada, Health Canada (2010)

64 Op. cit. Environment Canada, Health Canada (2010)