Dodecaaluminium trimolybdenum dodecaoxide

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

PNEC freshwater (intermittent releases):

1 mg/L

STP

Hazard assessment conclusion:

no hazard identified

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

The ecotoxicity databases on the effects of soluble and insoluble aluminium and molybdenum compounds to aquatic, soil- and sediment-dwelling organisms are extensive. It should be noted that the environmental fate pathways and ecotoxicity effects assessments for aluminium metal and aluminium compounds as well as for molybdenum metal and molybdenum compounds is based on the observation that adverse effects to aquatic, soil- and sediment-dwelling organisms are a consequence of exposure to the bioavailable ion, released by the parent compound. The result of this assumption is that the ecotoxicological behaviour will be similar for all soluble aluminium and molybdenum substances used in the presented ecotoxicity tests.

As aluminium molybdenum oxide has shown to be only slightly soluble in water (pH 4.5, 7d) and poorly soluble in ecotoxicity test media (pH 7.5-8.5, 96h), it can be assumed that under environmental conditions in aqueous media, the components of the substance will be present in a bioavailable form only in minor amounts (Mo) or hardly, if at all (Al). Within this dossier all available data from soluble and insoluble aluminium and molybdenum substances are taken into account and used for the derivation of ecotoxicological and environmental fate endpoints, based on the aluminium ion and molybdenum ion. All data were pooled and considered as a worst-case assumption for the environment. However, it should be noted that this represents an unrealistic worst-case scenario, as under environmental conditions the concentration of soluble Al³⁺and MoO₄^2-ions released from aluminium molybdenum oxide is negligible (Al) or low (Al), respectively.

Information taken from Aluminium Consortium:

It is important to point out that the substance being registered in this dossier represents sparingly soluble forms of aluminium and not soluble metal salts. Soluble aluminium salts are not classified, therefore less soluble forms of aluminium are less hazardous and also not classified. Available data indicate that aluminium salts are relatively non toxic and this was sufficient for the EU Classification and Labelling Committee to determine that there was no need for classification of aluminium chloride. Therefore it is also concluded that aluminium massive and sparingly soluble forms of aluminium are highly insoluble and non-hazardous. The sections above have provided data on a BLM model that can be used to assess potential for toxicity in the pH range of 5-6. Work is continuing on this model. 

Studies reported in the literature have been performed repeatedly with test solutions based on soluble salts with aluminium concentrations above that of its solubility limit. Due to physical effects of precipitated material most of these studies are meaningless for the investigation of intrinsic toxicity. Aluminium ions released to surface waters quickly form insoluble aluminium hydroxides in mixing zones. These colloids can sorb to fish gills resulting in asphyxiation and mortality in rare instances. In laboratory studies, reports of asphyxiation are common and true or intrinsic toxicity appears to be lacking. The rapid formation of the complex hydroxides in neutral and alkaline waters complicates the assessment for classification for several reasons. First, the observed mortality is does not appear to be due to intrinsic toxicity. Second, the LC and EC50 values are typically above 1 mg/L (there are a couple of values in the 0.5-1.0 mg/L range) and all of the effects values are above the solubility limit of aluminium hydroxide. A report on the solubility of Al in OECD test media is attached and was summarised at the January 26, 2010 meeting with ECHA (Blust et al. 2010). And third, there is a lack of consistency in reporting the LC/EC50 values as total, dissolved or monomeric in the literature. Recent studies performed by the European Aluminium Association demonstrate that the only reliable predictor of toxic effects to aquatic organisms is total aluminium. This has been demonstrated across a broad range of pH, DOC and hardness values. Hence, for classification purposes we chose to use “total” Al (i.e., non filtered samples) in the test media as the most appropriate parameter for reporting LC and EC50 values.

Conclusion on classification

Classification related key information

Solubility:

slightly soluble in water (pH 4.5, 7d) (Al: 2.24 - 27.21 mg/L, Mo: 21.46 – 140.59 mg/L);

poorly soluble in ecotoxicity test media (pH 7.5-8.5, 96h) (fish: 5.64 mg Mo/L and 0.14 mg Al/L at 100 mg/L loading, 96h;Daphnia: 3.97 mg Mo/L and 0.04 mg Al/L at 100 mg/L loading, 48h; algae: 5.08 mg Mo/L at 100 mg/L loading, 72h, Al not detectable)

 

Biodegradation in water: not applicable (inorganic substance)

 

Aquatic acute toxicity:

to fish:          96 h, LC₅₀(Danio rerio):  > 100 mg/L nominal (measured: 5.64 mg Mo/L, 0.14 mg Al/L after 96 h)

to aquatic invertebrates: 48 h, EC₅₀(Daphnia magna): > 100 mg/L nominal (measured: 3.96 mg Mo/L, 0.038 mg Al/L after 48 h)

to algae:        72 h, ErC₅₀(Desmodesmus subspicatus):  > 100 mg/L nominal (measured: 5.08 mg Mo/L, Al not detectable after 72 h)

 

Aquatic chronic toxicity:

to fish:          78 d, EC10 (Oncorhynchus mykiss):  43.2 mg Mo/L, RA; 0.078 mg Al/L, RA (measured concentrations)

to aquatic invertebrates: 21 d, NOEC (Daphnia magna):  49.9 mg Mo/L, RA; 0.021 mg Al/L, RA (measured concentrations)

to algae:        21 d, NOErC (Desmodesmus subspicatus):   > 100 mg/L nominal (measured: 5.08 mg Mo/L, Al not detectable after 72 h)

 

Classification justification according to CLP

Based on the data above, there is no evidence of rapid environmental transformation of aluminium molybdenum oxide, but a low bioaccumulation potential can be assumed. The acute aquatic toxicity L(E)C50 values are > 1 mg/L for fish, aquatic invertebrates and algae at nominal concentrations and measured concentrations for Mo. Low measured concentrations of Al indicate that Al is hardly present in a bioavailable form. Valid chronic toxicity data are available - the lowest NOECs are > 1 mg/L for fish, aquatic invertebrates and algae for the substance itself at nominal concentrations and measured concentrations for Mo (algae), and for analogue molybdenum substances (fish, aquatic invertebrates). For analogue aluminium substances, lower NOECs were obtained, however these values were not considered for the assessment as it can be assumed that under environmental conditions in aqueous media, aluminium predominantly exists as insoluble species (Al(OH)₃) and hence, will be present in a bioavailable form only in minor amounts, if at all.

Therefore, following the “Guidance on the application of the CLP criteria” (ECHA, 2012) according to Regulation (EC) 1272/2008 (CLP), aluminium molybdenum oxide does not need to be classified and labelled as environmental hazard according to the Regulation (EC) No.1272/2008 (CLP) and the Regulation (EU) No. 286/2011 (2^ndATP).

 

M-factor for acute aquatic toxicity:      -
M-factor for chronic aquatic toxicity:   -

 

Classification justification according to DSD

Based on the data above, there is no evidence of rapid environmental transformation of aluminium molybdenum oxide, but a low bioaccumulation potential can be assumed. The acute aquatic toxicity L(E)C50 values are > 100 mg/L to fish, aquatic invertebrates and algae (nominal concentrations). Therefore, aluminium molybdenum oxide does not need to be classified and labelled as environmental hazard according to Directive 67/548/EEC.