Dodecaaluminium trimolybdenum dodecaoxide

Toxicity to birds

Additional information

No data on toxicity to birds 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 (Al) impairment in birds and mammals is mainly related to its disruptive effect on calcium homeostasis as well as phosphorus metabolism. This adverse effect leads to muscle weakness and decreased growth rates (Scheuhammer 1987). This metal also induces defective eggshell formation and intrauterine bleeding in Al-contaminated pied flycatchers (Ficedula hypoleuca; Nyholm, 1981). Scheuhammer (1991) examined the accumulation of aluminium in different species of ducklings dwelling in an acidified lake in Ontario, Canada. The species of ducks chosen for study have significantly different feeding habits. Young black and ring-necked ducks feed mainly on surface insects in near-shore vegetation; goldeneye and hooded mergansers are pursuit divers that prey on large, mobile invertebrates, although goldeneye take more benthic material, and hooded mergansers probably take some fish and amphibians as well; common mergansers are almost exclusively fish-eaters. Tissue metal concentrations accumulated by ducklings during their first few months of life indicate that dietary exposure of ducklings to toxicologically relevant levels Al is unlikely to occur in acidified environments. Kidney-A1concentrations ranged from undetectable (< 0.01 µg/g) to about 5 µg/g.

Avian toxicity data are used in the assessment of secondary poisoning risks for the aquatic and terrestrial food chains. The available evidence shows the absence of aluminium biomagnification across trophic levels both in aquatic and terrestrial food chains. The existing information suggests not only that aluminium does not biomagnify, but rather that it tends to exhibit biodilution at higher levels of the food chain. The potential for massive aluminium, powders or aluminium oxide to be consumed by birds is extremely negligible. Therefore the need for additional testing for secondary poisoning can be waived. More detailed information can be found in the attached document (White paper on waiving for secondary poisoning for Al & Fe compounds final report 02-02-2010. pdf).

Molybdenum

Only one reliable NOEC value was found for birds (Davies et al., 1960) with a value of 400 mg /kg dry weight. The other study by Reid et al. (1956) resulted in unbounded NOECs.

In terms of secondary poisoning, an assessment can be made considering, in combination, the BAF values with the toxicity in birds. the modest BAF in combination with the low toxicity in birds would suggest that the soil-earthworm-bird pathway is unlikely to pose any risk to wildlife and that the generic PNECsoil will drive the risk assessment.