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EC number: 287-574-8 | CAS number: 85536-87-4
- 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

Endpoint summary
Administrative data
Description of key information
Stability
Hydrolysis
Based on results of the hydrolysis study, the half life at 25°C is estimated to be > 1 year, 6 days, and < 1 day at pH 4, 7, and 9, respectively.
Biodegradation
Biodegradation in water: screening test
The ready biodegradability of the test substance was tested in the modified OECD 301E screening test and the inherent biodegradability in a modified Zahn-Wellens test. No biodegradation was observed in either test system.
Transport and distribution
Adsorption/desorption
A study on adsorption and desorption does not need to be conducted because the test substance has a low octanol water partition coefficient (log Kow <-2.61) and the adsorption potential of this substance is related to this parameter.
Additional information
It should be noted that the test substance is not considered as posing a hazard to the aquatic environment.
The test substance, Reactive Orange 72/78, is a solid under all environmental conditions and is highly soluble in water. It has a low volatility (based on the high melting / boiling point and high molecular weight) and a low affinity for soil / sediment (based on the partition coefficient value of log Kow ≤ -2.61). As such, any environmental release will result in virtually all of the substance compartmentalising into water compartments, with little release directly to atmosphere or compartmentalising to soil/sediment compartments.
Any potential exposure to the environment is predicted to result in rapid redistribution to water; due to its low volatility, high water solubility and partitioning values indicates that the majority of the substance would eventually partition to water rather than to soil and sediment should it be released to the environment.
A Level III fugacity model was conducted in the US EPA EPISUITE which assumes steady-state but not equilibrium conditions.The Level III model in EPI Suite predicts partitioning between air, soil, sediment and water using a combination of default parameters and various input parameters.This model has been used to calculate the theoretical distribution of the highest % component substance between four environmental compartments (air, water, soil, sediment) at steady state in a unit world.
Table 1. Partitioning model Reactive Orange 72/78
Compartment |
Distribution [%] |
Half-life [h] |
Air |
3.8E-7 |
15.1 |
Water |
7 |
4.32E3 |
Soil |
92.8 |
8.64E3 |
Sediment |
0.186 |
3.89E4 |
It is proposed that although the majority of the substance distributes to the soil compartment within the model, the high solubility in water indicates that the substance is more likely to distribute to water – e. g. soil pore water.
This assumption is confirmed by the model for the STP Overall Chemical Mass Balance in the US EPA EPI SUITE, which shows that 98% of the influent of the dye is in the water phase:
Table 2. STP Overall Chemical Mass Balance
|
g/h |
mol/h |
percent |
Influent |
1.00E+001 |
1.6E-002 |
100.00 |
Primary sludge |
2.50E-002 |
4.0E-005 |
0.25 |
Waste sludge |
1.50E-001 |
2.4E-004 |
1.50 |
Primary volatilization |
5.45E-023 |
8.8E-026 |
0.00 |
Settling volatilization |
1.49E-022 |
2.4E-025 |
0.00 |
Aeration off gas |
3.66E-022 |
5.9E-025 |
0.00 |
Primary biodegradation |
1.76E-003 |
2.8E-006 |
0.02 |
Settling biodegradation |
5.27E-004 |
8.5E-007 |
0.01 |
Aeration biodegradation |
6.93E-003 |
1.1E-005 |
0.07 |
Final water effluent |
9.82E+000 |
1.6E-002 |
98.15 |
Total removal |
1.85E-001 |
3.0E-004 |
1.85 |
Total biodegradation |
9.22E-003 |
1.5E-005 |
0.09 |
Reactive Orange 72/78 displays a low ready biodegradability in that it achieved < 10% biodegradation in a modified OECD screening test and was not inherently biodegradable, achieving 4% biodegradation in a Zahn-Wellens test. Microbial decolourization of azo dyes in an anaerobic environment occurred as a result of reduction of azo bonds, leading to decolourized metabolites. No ready biodegradation of these metabolites was expected in the anaerobic system. However, these metabolites could be further diminished by means of either biodegradation or autoxidation under subsequent aerobic treatment. The mixed bacterial cultures decolorized three structurally dissimilar azo dyes, suggesting that anaerobic decolourization was not a specific process (Supaka 2003). It was clear that the majority of the colour removal occurred in the anaerobic stage.
The substance is expected to hydrolyse under normal environmental conditions. Experimental studies on hydrolytic effects of a structural analogue demonstrated that the substance does undergo rapid hydrolysis at environmentally relevant pHs, (t½= 6 days at pH7 and < 1 day at pH9), indicating the potential for significant removal by hydrolysis. At use conditions during dyeing (pH > 10 at ≥ 60°C) the substance is hydrolytically unstable. At 50°C and pH9, more than 99% of the substance was degraded at the first measure point of 1.5 hours. As such, degradation is anticipated via this route. Studies on direct phototransformation in water are not available but it was found that the sulfonated azo dyes can be destroyed by UV photooxidation process (Saliha 2004). The kinetics of the degradation depends on the azo, benzene and naphthalene groups of the dyes. It was found that the first step of the degradation is related to cleavage of azo bond of the molecule and naphthalene ring which leads to further degradation until complete mineralization. It is concluded, therefore, that abiotic processes would contribute significantly to the depletion of the substance within the environment.
Reactive Orange 72/78 has an estimated log Kow of ≤ -2.61. This value indicates that possible bioaccumulation in the food chain is not anticipated. Given the fact that the substance is subject to hydrolysis at biologically relevant pHs, it is anticipated that bioaccumulation of the substance itself would not occur, as hydrolytic effects in association with metabolic effects would result in removal of the substance. Based on its high water solubility, low partition coefficient and fairly rapid hydrolysis rate at environmentally relevant pHs, it can be concluded that it is unlikely that Reactive Orange 72/78 could potentially be persistent within the environment.
Adsorption to soil is deemed to be low, based on the very low partition coefficient value and high water solubility. Such a low potential indicates that the substance is unlikely to bind tightly to soils and sediments and instead partition almost exclusively to water. As such, significant exposure related effects to sediment and soil dwelling organisms are considered to be negligible.
Based on its high water solubility and low partition coefficient it can be concluded that it is unlikely that Reactive Orange 72/78 could potentially be persistent within the environment in its registered form. Abiotic effects within the environment will result in eventual removal from the environment and hence significant contact with the organisms in the food chain can considered to be minimised.
Finally, Reactive Orange 72/78 demonstrates low acute toxicity in mammalian studies therefore in the event of exposure to environmental organisms. Effects due to secondary poisoning can be excluded.
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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