Dodecaaluminium trimolybdenum dodecaoxide

Toxicity to other aquatic organisms

Additional information

No data on toxicity to other aquatic organisms 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

No data on the toxicity to other aquatic organisms are available.

Molybdenum

Freshwater:

For the snail Lymnaea stagnalis, the 28d-EC₁₀ value of 221.3 mg/L is retained for assessment purposes. As mentioned previously, EC₁₀ values are preferred over NOEC values as the latter are test-dependent values. In this specific case the 28d-EC₁₀ of 221.3 mg/L is slightly higher than the 28d-NOEC of 200 mg/L for this endpoint. The latter concentration level, however, only caused 5-6% effect on growth, i.e. well below the effect level of 10% that is considered relevant for chronic toxicity. The 28d-LOEC is almost a factor of 2 higher than the 28d-EC₁₀.

 

For the frog Xenopus laevis, the 4d-EC₁₀ value of 115.9 mg/L (effect parameter: malformation) is retained. This 4d-EC₁₀ is almost a factor of 5 higher than the 4d-NOEC for this effect parameter. It should be noted, however, that the 8% malformations associated with this NOEC was also found at an exposure level of 87.3 mg/L. The lowest actual concentration that resulted in more than 10% effect was 177 mg/L, i.e. a factor of 1.5 higher than the derived 4d-EC₁₀. The low NOEC is the result of the 10% effect found at an exposure concentration of 48.7 mg/L and the low inter-replicate variation, resulting in a significant effect compared to the control. Taking into account that 8% and 12% effect was observed at concentration levels of 87.3 mg/L and 177 mg/L, respectively, a 4d-EC₁₀ of 115.9 mg/L for X. laevis is considered relevant and reliable.

Author, year	Species	Endpoint	Value [mg Mo/L]
De Schamphelaere et al., 2008	Lymnaea stagnalis	28 d NOEC (growth rate) 28 d EC10	200 221.3
De Schamphelaere et al., 2008	Xenopus laevis	4 d EC10 (morphology, malformation)	115.9
		4 d NOEC (morphology, malformation)	22.4/87.3

Marine:

For the oyster Crassostrea gigas (Aquasense, 2009) an 48h-EC₁₀ value of 1174 mg Mo/L (endpoint: larval development) is retained for the marine compartment. The 72h-NOEC value for this endpoint was 1100 mg Mo/L. The EC₁₀ value, however, is preferred over the NOEC value as the latter is a test design-dependent value.

 

For the sand dollar Dendraster excentricus a 48h-EC₁₀ value of 233.6 mg Mo/L (endpoint: proportion of normal developed larvae) is retained for the marine compartment. Comparable (though slightly higher) values were noted for other endpoints, e.g. number of normal larvae (254.5, 292.1 mg Mo/L).

The 72h-NOEC value for these endpoints was 217.9 mg Mo/L (exception: mortality: 438.4 mg Mo/L). The EC₁₀ value, however, is preferred over the NOEC value as the latter is a test design-dependent value.

 

For the sea urchin Strongylocentrotus purpuratus (Parametrix, 2008) the 94h-EC₁₀ value of 325.8 mg Mo/L is retained for the marine environment (endpoint: combined normal proportion). A comparable, though slightly higher 94h-EC₁₀ value of 483 mg Mo/L was determined for the endpoint ‘normal proportion’. NOEC values for these endpoints were 80.2 -264.5 mg Mo/L. EC₁₀ values, however, are preferred over NOEC values as the latter are test design-dependent values.

 

For the mussel Mytilus edulis (Morgan et al, 1986) an 48h-EC₁₀value of 4.4 mg Mo/L (endpoint: larval development) is retained for the marine compartment.

Author, year	Species	Endpoint	Value [mg Mo/L]
Aquasense, 2009	Crassosstrea gigas	48 h EC10	1174
		48 h NOEC	1100
Parametrix, 2008	Dendraster exentricus	48 h EC10	233.6
		48 h NOEC	217.9
Parametrix, 2010	Strongylocentrotus prupuratus	94 h EC10 94 h NOEC	325.8 80.2 -264.5
Morgan et al., 1986	Mytilus edulis	48 h EC10	4.4