Manganese alumina pink corundum

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance is highly insoluble in water, hence indicating that aquatic toxicity is unlikely to occur

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
According to Annex VIII, Column 2, Section 9.1.4. of Regulation (EC) 1907/2006, the test for activated sludge respiration inhibition does not need to be conducted “if there are mitigating factors indicating that aquatic toxicity is unlikely to occur, for instance if the substance is highly insoluble in water”.

Manganese alumina pink corundum 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. At a loading of 1 mg/L and pH 6, dissolved concentrations of 0.29 and 0.042 µg/L aluminium and 10.66 and 8.91 µg/L manganese were measured after 7 and 28 days, respectively. Thus, the rate and extent to which Manganese alumina pink corundum produces soluble (bio)available ionic and other aluminium- and manganese-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 Manganese alumina pink corundum is expected to determine its behaviour and fate in the environment, and subsequently its potential for ecotoxicity.

Proprietary studies are not available for Manganese alumina pink corundum. The poorly soluble substance Manganese alumina pink corundum is evaluated by comparing the dissolved metal ion levels resulting from the transformation/dissolution test after 7 and 28 days at a loading rate of 1 mg/L with the lowest acute and chronic ecotoxicity reference values (ERVs) as determined for the (soluble) metal ions. The ERVs are based on the lowest EC50/LC50 and NOEC/EC10 values for algae, invertebrates and fish. Acute and chronic ERVs were obtained from the Metals classification tool (MeClas) database as follows: For aluminium, acute ERVs of 1,040 µg Al/L at pH 6 and 3,390 µg Al/L at pH 8 were derived, and a concern for long-term (chronic) toxicity of aluminium ions was not identified (no classification). The acute and chronic ERVs of manganese are 3,200 and 550 µg Mn/L, respectively. The determined dissolved aluminium and manganese concentrations of 0.29 µg Al/L and 10.66 µg Mn/L in the T/D test after 7 days at pH 6 are significantly lower than the corresponding lowest short-term ERVs (1,040 µg Al/L at pH 6 and 3,200 µg Mn/L). Thus, the substance Manganese alumina pink corundum is not sufficiently soluble to cause short-term toxicity at the level of the acute ERVs (expressed as EC50/LC50). Due to the lack of a long-term aquatic hazard potential for soluble aluminium ions, only manganese concentrations and the corresponding chronic ERV is taken into account. The dissolved manganese concentrations of 8.91 µg Mn/L at a loading of 1 mg/L after 28 days at pH 6 is significantly lower than the corresponding long-term ERV of 550 µg Mn/L. Thus, the substance Manganese alumina pink corundum is not sufficiently soluble to cause short-term or long-term toxicity at the level of the acute or chronic ERVs (expressed as EC50/LC50 or NOEC/EC10, respectively).

In accordance with Figure IV.4 “Classification strategy for determining acute aquatic hazard for metal compounds” and 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 Manganese alumina pink corundum is poorly soluble and does not meet classification criteria for acute (short-term) and chronic (long-term) aquatic hazard.

Manganese alumina pink corundum is poorly soluble. Based on the poor solubility and the corresponding lack of a toxic potential, inhibition of activated sludge respiration or toxicity to microorganisms is not expected. In accordance with Annex VIII, Column 2, Section 9.1.4. of Regulation (EC) 1907/2006, the test for activated sludge respiration inhibition is not necessary.