Dodecaaluminium trimolybdenum dodecaoxide

Toxicity to terrestrial arthropods

Description of key information

EC10 (28d) = 37.9 mg added Mo/kg dw (measured) for Folsomia candida (ISO 11267) (read-across from sodium molybdate dihydrate)

Additional information

No data on toxicity to terrestrial arthropods are available for aluminium molybdenum oxide. However, there are reliable data available for different analogue substances.

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 (Mo), respectively.

Aluminium

Aluminium, aluminium powders and aluminium oxide are non hazardous (not classified for the environment). Aluminum (Al) is the most commonly occurring metallic element, comprising eight percent of the earth's crust (Press and Siever, 1974) and is therefore found in great abundance in both the terrestrial and sediment environments. Concentrations of 3-8% (30,000-80,000 ppm) are not uncommon. The relative contributions of anthropogenic aluminium to the existing natural pools of aluminium in soils and sediments is very small and therefore not relevant either in terms of added amounts or in terms of toxicity. Based on these exposure considerations additional sediment and/or soil testing is not warranted. More information about exposure based waiving for aluminium in soil and sediments can be found in attached document (White paper on waiving for secondary poisoning for Fe and Al compounds final report 25-01-2010. doc).

Molybdenum

For the arthropod invertebrate toxicity assay, Folsomia candida, was used as a test species. Only 3 soils resulted in reliable, bounded NOEC values. In all 8 other soils, no toxic effect was observed at the largest dose tested (unbounded NOEC values between >2628 and 3395 mg added Mo/kg dw. The reliable NOEC/EC10 values taken forward ranged from 37.9 to 1865 mg added Mo/kg dw. All data are based on added measured Mo concentrations in soil.

Not much could be concluded regarding the results of the 3 aged soils given that already in the spiked soils, no effects were observed. In one of the 3 aged soils, an effect was noted, although at a concentration greater than the unbounded NOEC in the spiked soil.