Registration Dossier
Registration Dossier
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Diss Factsheets
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EC number: 289-178-0 | CAS number: 86089-09-0
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
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Endpoint summary
Administrative data
Key value for chemical safety assessment
Genetic toxicity in vitro
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed (negative)
Genetic toxicity in vivo
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed (negative)
Additional information
This dossier is one of several dossiers prepared under the auspices of the REACH Molybdenum Consortium (“MoCon”). To avoid unnecessary (animal) testing, a comprehensive grouping and read-across concept has been developed amongst several molybdenum containing substances. This grouping/category approach is described in detail in a separate report, in accordance with the ECHA's "Read-Across Assessment Framework" (RAAF). This document is attached to section 13 in the technical dossier and to the CSR. This endpoints summary is therefore applicable to all substances in the category.
The following guideline-conform, highly reliable genotoxicity tests with a soluble molybdenum substance (sodium molybdate) are available:
- an AMES bacterial reverse mutation assay (Beevers, 2009),
- an in vitro micronucleus assay in human lymphocytes (Taylor, 2009),
- an in vitro gene mutation assay (tk) in mouse lymphoma cells (Lloyd, 2009), and
- an in vivo micronucleus study in rat bone marrow (Cockburn, 2021). This study was commissioned by the International Molybdenum Association, and conducted by Charles River Laboratories USA in December 2020, because it is a required datapoint under Korea-REACH for substances > 100 tonnes.
All four tests produced unequivocally negative results, and thus provide strong evidence for an absence of concern for genotoxic effects of molybdenum substances. This includes the OECD TG 474 in vivo micronucleus study in rat bone marrow, tested to the limit dose, which was conducted to comply with Korea-REACH for substances >100 tonnes per year. Since the substance tested represents a highly soluble molybdate, and all molybdenum substances in the MoCon read-across group, regardless of their solubility, speciation and valence have been shown to transform rapidly to molybdate anions upon dissolution in aqueous media, these results can be read across to all other molybdenum substances in the group without restriction. Because of their ubiquitous physiological presence in biota and/or their essential role in human physiology, the sodium/ammonium/calcium/iron moieties in some of the molybdenum substances are not considered to be of concern for genotoxicity (see read-across justification document in section 13 of the technical dossier, chapter on "formation of non-common compounds").
In conclusion, hazard classification for genotoxicity is not required.
Apart from these high quality, reliable GLP test results, a large number of published studies exist of varying quality and extent of documentation, which is why these were subjected to a detailed quality and reliability screening, the outcome of which can be summarized as follows:
(i) unequivocally negative results were obtained in guideline-conform, valid bacterial reverse mutation assays for high purity (moderately soluble) molybdenum trioxide (studies by Jones, 2004 and Zeiger et al., 1992). Negative results were also obtained in the same test system with (highly soluble) sodium and ammonium molybdates, which however from a perspective of formal regulatory compliance are considered incomplete because of the selected tester strains (studies by Armitage, 1997 and Kubo et al. 2002).
(ii) all in vitro clastogenicity test considered as assignable and reliable with or without restrictions are negative.
(iii) in view of the unequivocally negative results in all three in-vitro key studies, the conduct of any further in vivo testing would not be required under EU REACH. However an in vivo micronucleus study (OECD TG 474) was conducted in 2020 to comply with data requirements for Korea-REACH substances >100 tonnes per year and is therefore also reported here. This study was negative. Already available in vivo studies were subjected to a thorough evaluation and were found to be seriously flawed and of poor quality, and were thus assigned reliability grades of either 3 or 4. In this context it is explicitly noted that the studies published by Titenko-Holland (1998) have already previously been critiqued as deficient and disregarded by the Classification and Labelling Committee of the ECB during discussions on molybdenum trioxide in 2004.
Short description of key information:
Four (three in vitro, one in vivo) guideline-conform, highly reliable genotoxicity tests produced unequivocally negative results, and thus provide strong evidence for an absence of concern for genotoxic effects of molybdenum substances, which is supported by reliable supplementary data.
Justification for classification or non-classification
Based on the review of key experimental studies as well as supportive information on genetic toxicity, no hazard classification is required for genotoxicity/mutagenicity.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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