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Diss Factsheets
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EC number: 231-551-7 | CAS number: 7631-95-0
- 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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Toxicity to other above-ground organisms
Administrative data
Link to relevant study record(s)
Description of key information
Only one good quality study is available. In this study by Kincaid (1980), the effect of Molybdenum in drinking water on cattle was studied. No effects were found at the highest tested concentration (50 mg Mo/L).
All experimental studies in which the effect to ruminants of increased levels of molybdenum in feed were studied, were of insufficient quality as copper levels in the feed of the control treatments were below the required or recommended levels against primary deficiency. Several of the field studies suffered from the same shortcoming.
Nonetheless, molybdenosis is a well recognised phenomenon that has been observed in the field, and that requires proper assessment. It has further been observed that the onset of molybdenosis is highly dependent of the dietary copper level, its bioavailability to the ruminant and the dietary Cu:Mo ratio. Derivation of one specific PNECoral for molybdenosis can therefore not be considered relevant. Instead, it is more relevant to use a dietary Cu:Mo ratio as the threshold.
Based on an in-depth review by Smolders and Buekers (2009) making use of a weight-of-evidence approach the proposed minimum dietary Cu:Mo ratio threshold is 1.30 (For the avoidance of doubt, this means there should be 30% more copper than molybdenum in the diet). This value was derived as the 90th percentile of on an extensive dataset on cattle composed of 12 experimental and 7 field studies. At lower ratios, there is a risk of molybdenum-induced copper deficiency.
This threshold is also shown to be protective for other ruminant species such as sheep and deer.
Key value for chemical safety assessment
- Long-term EC10, LC10 or NOEC for mammals:
- 200 mg/kg food
Additional information
Toxicity to ruminants
Molybdenosis is found only in ruminants such as cattle, deer, sheep and is caused by molybdenum induced copper deficiency, but is not found in non-ruminants. Effects in cattle correspond with symptoms observed when dietary copper is deficient e.g. diarrhoea, alopecia (loss of hair), achromatrichia (change in hair colour), reduced milk yield and loss of body weight. This effect has been studied extensively, especially in cattle, and in, for example, the UK Somerset area and New Zealand where the soils and pastures are naturally enriched with molybdenum.
A detailed description of this phenomenon is gived in the Background Document “Environmental effects assessment of molybdenum”, which is attached in the technical dossier in IUCLID Section 13, and provided more information on mode of action, required daily intakes of Cu for ruminants, the influence of dietary Cu:Mo ratios on molybdenosis for ruminants, and results of experimental field studies on ruminants with molybdenum. Information on the use of sodium molybdate as a remedy against copper toxicity is also included in this Background Document, together with an outline of risk management measures to prevent molybdenosis in ruminants living in the vicinity of a local industrial site emitting molybdenum.
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.
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