Registration Dossier

Diss Factsheets

Ecotoxicological information

Long-term toxicity to aquatic invertebrates

Administrative data

Endpoint:
long-term toxicity to aquatic invertebrates
Data waiving:
study technically not feasible
Justification for data waiving:
other:
Justification for type of information:
JUSTIFICATION FOR DATA WAIVING
Cobalt zinc aluminate blue spinel can be considered environmentally and biologically inert due to the characteristics of the synthetic process (calcination at a high temperature of approximately 1000°C), rendering the substance to be of a unique, stable crystalline structure in which all atoms are tightly bound and not prone to dissolution in environmental and physiological media. This assumption is supported by available transformation/dissolution data (Grané, 2010) that indicate a very low release of pigment components at pH 6, the pH that maximises dissolution. Transformation/dissolution tests at a loading of 1 mg/L and pH 6 resulted in dissolved cobalt and zinc concentrations that remained below the LOD (i.e. < 0.11 µg Co/L and < 0.07 µg Zn/L, respectively) during the 28-d test. Dissolved aluminium concentrations after 7 and 28 days amount to 48.75 and 23.48 µg Al/L, respectively. Thus, the rate and extent to which Cobalt zinc aluminate blue spinel produces soluble (bio)available ionic and other aluminium-, cobalt- and zinc-bearing species in environmental media is limited. Hence, the pigment can be considered as environmentally and biologically inert during short- and long-term exposure. The poor solubility of Cobalt zinc aluminate blue spinel is expected to determine its behaviour and fate in the environment, and subsequently its potential for ecotoxicity.

Proprietary studies are not available for Cobalt zinc aluminate blue spinel. The poorly soluble substance Cobalt zinc aluminate blue spinel is evaluated by comparing the dissolved metal ion levels resulting from the transformation/dissolution test after 28 days at a loading rate of 1 mg/L with the lowest chronic ecotoxicity reference values (ERVs) as determined for the (soluble) metal ions. The ERVs are based on the lowest EC10/NOEC values for algae, invertebrates and fish. In accordance with the Classification and Labelling Committee in 1999 (see report 013-003-00-7 submitted to the C&L Committee, 1999) a chronic ERV for dissolved aluminium ions has not been derived since a concern for long-term (chronic) toxicity of aluminium ions was not identified (no classification). Due to the lack of a chronic hazard potential for dissolved aluminium ions, only cobalt and zinc concentrations and the respective chronic ERVs are taken into account. Respective chronic ERVs were obtained from the Metals classification tool (MeClas) database and are for cobalt 7.6 µg Co/L, for zinc 82 µg Zn/L at pH 6 and 19 µg Zn/L at pH 8. Since cobalt and zinc ion concentrations remained below the LOD (i.e. < 0.11 µg Co/L and < 0.07 µg Zn/L, respectively) during the 28-days T/D test and are well below respective chronic ecotoxicity ERVs, there is not a concern for long-term (chronic) toxicity of cobalt and zinc ions. Hence, the substance Cobalt zinc aluminate blue spinel is not sufficiently soluble to cause long-term toxicity at the level of the chronic ERVs (expressed as NOEC/EC10).

In accordance with Figure IV.5 „Classification strategy for determining long-term aquatic hazard for metal compounds “of ECHA Guidance on the Application of the CLP Criteria (Version 5.0, July 2017) and section 4.1.2.10.2. of Regulation (EC) No 1272/2008, the substance Cobalt zinc aluminate blue spinel is poorly soluble and does not meet classification criteria for chronic (long-term) aquatic hazard.

In accordance with Annex XI, Section 2 of Regulation (EC) 1907/2006, “Testing for a specific endpoint may be omitted, if it is technically not possible to conduct the study as a consequence of the properties of the substance”.

Cobalt zinc aluminate blue spinel is poorly soluble and unlikely to cross biological membranes. Hence, Cobalt zinc aluminate blue spinel can be considered environmentally and biologically inert during aquatic exposure (please see above). For a highly insoluble substance such as Cobalt zinc aluminate blue spinel, it may neither be possible nor relevant to try and conduct aquatic toxicity tests, as it is difficult to maintain a quantifiable and constant concentration of the substance in the environmental test medium. In accordance with the generic testing recommendations in the “Executive summary of the MISA 2 workshop (https://echa.europa.eu/misa)” for difficult to test substances, “The Water Accommodated Fraction (WAF) method (see REACH and OECD guidance on difficult to test substances), should not be used for metals. The reason is that this method often uses nominal loadings and lacks the pH and surface relationships necessary to estimate the potential hazard. Direct aquatic ecotoxicity testing of metals and SSMCs is in principle not recommended. However, if used or needed (e.g. for complex materials like UVCBs) then it should be conducted based on the dissolved fraction(s) of the T/D medium, at the appropriate pH (pH that dilutes the most).”

Since the substance Cobalt zinc aluminate blue spinel is not sufficiently soluble to cause long-term toxicity at the level of the chronic ERVs (expressed as NOEC/EC10), it is neither technically possible in accordance with Annex XI, Section 2 of Regulation (EC) 1907/2006 nor scientifically justified to conduct any further aquatic toxicity study, including long-term toxicity to invertebrates with Cobalt zinc aluminate blue spinel.

Data source

Materials and methods

Results and discussion

Applicant's summary and conclusion