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Diss Factsheets
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EC number: 231-778-1 | CAS number: 7726-95-6
- 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
Description of key information
Additional information
Stability
Bromine is unstable in water hydrolysing rapidly. The rate constant for bromine hydrolysis is in the range of 97sec-1(Becker RH et al, 2001).
The identity of the degradation products of bromine have been outlined in Lewis S et al (1994). In aqueous solutions made with pure water, bromine hydrolyses to hypobromous acid (HOBr) (free bromine) which further dissociates to give hypobromite ions (OBr-) and hydrogen ions (H+) with the degree of dissociation being highly pH dependent. An overview of the dissociation of hypobromous acid over various pH values are given below in Table 1.
Table 1: Effect of pH on Hypobromous acid
pH |
Bromine |
6.0 |
5 % Br2 95 % HOBr |
7.0 |
99 % HOBr 1 % OBr- |
8.0 |
90 % HOBr 10 % OBr- |
9.0 |
50 % HOBr 50 % OBr- |
As under the exposure conditions covered in the registration dossier concentrations of bromine are low, water is in excess and the hydronium ion concentration is buffered to physiological pH values, the equilibrium is shifted to the hydrolysis products. The above reaction is pseudo first order. With the rate constant k1 of 97 s-1 a half-live of ln2 / 97 = 0.007 s can be calculated which confirms the rapid hydrolysis of the substance.
In natural waters, bromine reacts with ammonia and organic nitrogenous materials to form bromamines. Bromine will react more quickly with other organic materials in water, to form other chemicals analogous to chlorinated products (e.g. bromoform, bromophenols, bromoaldehydes, bromoacetonitriles, bromoacetic acids, bromoketones, bromohydrins). In seawater, the likely predominant species will be inorganic bromamines (especially dibromamine) because of the relatively high ammonia concentrations. As a result, because of the limited stability of inorganic bromamines, it is likely that the total bromine residual will decay fairly rapidly to bromide. In river waters, with typically low ammonia concentrations, and relatively high organic carbon contents, it is likely that higher concentrations of inorganic and organic bromamines would result. In neither case, is there likely to be any free bromine remaining after a short contact period. This could be difficult to confirm since standard analytical procedures are incapable of distinguishing free and combined bromamines (i.e. incapable of distinguishing hypobromous acid and the inorganic bromamines. If any free bromine should persist in an open environment, it would be destroyed by photolysis yielding bromide, and possibly bromate.
Biodegradation
Bromine is an inorganic substance and does not under go biodegradation to form carbon dioxide.
Bioaccumulation
Estimated log Kows for bromine are 1.03 and 1.49 (Annex VII Section 7.8), so it has a low potential for bioaccumulation. The Canadian Council of Resource and Environmental Ministers (1987) concluded for freshwater organisms, since chlorine and chloramines do not appear to have any potential for bioaccumulation or bioconcentration, it is reasonable to assume that this is probably the case for bromine and bromamines.
Transport and distribution
Adsorption of bromine itself is unlikely. Negative anions such as bromide are known not to sorb to soil. Bromide itself has been used to monitor ground water flow through soil; its mobility in soil is similar to water.
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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