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EC number: 225-935-3 | CAS number: 5160-02-1
- 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

Additional information on environmental fate and behaviour
Administrative data
- Endpoint:
- additional information on environmental fate and behaviour
- Remarks:
- Dispersion stability in simulated environmental media
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 2019
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 2 019
- Report date:
- 2019
Materials and methods
Test guideline
- Qualifier:
- according to guideline
- Guideline:
- other: OECD 318
- GLP compliance:
- yes (incl. QA statement)
Test material
- Reference substance name:
- Barium bis[2-chloro-5-[(2-hydroxy-1-naphthyl)azo]toluene-4-sulphonate]
- EC Number:
- 225-935-3
- EC Name:
- Barium bis[2-chloro-5-[(2-hydroxy-1-naphthyl)azo]toluene-4-sulphonate]
- Cas Number:
- 5160-02-1
- Molecular formula:
- C17H13ClN2O4S.1/2Ba
- IUPAC Name:
- barium(2+) bis(5-chloro-2-[(1E)-2-(2-hydroxynaphthalen-1-yl)diazen-1-yl]-4-methylbenzene-1-sulfonate)
- Test material form:
- solid: nanoform
Constituent 1
Results and discussion
Any other information on results incl. tables
At any of the time points mentioned in the TG-318, the influence of Ca is critical. Regardless of pH, the pigment is categorized at the 24h-sampling time as “instable” in 10 mM Ca, representing high water hardness. At 6h, most media induce “intermediate stability”, and only one medium (0 mM Ca, pH 9) induces a stability above 90%. At 24h, all media at 0 mM Ca and 1 mM Ca induce an intermediate stability between 60% and 87%. The stabilities systematically decrease over time, decrease slightly between 0 mM Ca and 1 mM Ca. The difference between pH 4 and pH 7 is low, but pH 9 systematically induces a slightly higher stability.
Table 1: Full results of the dispersion stability in the presence of NOM
Ca(NO3)2 |
Stability after 6h |
Standard deviation |
Stability after 15h |
Standard deviation |
Stability after 24h |
Standard deviation |
|
[mM] |
[%] |
[%] |
[%] |
[%] |
[%] |
[%] |
|
pH 4 |
0 |
84.2 |
0.7 |
75.3 |
1.2 |
64.5 |
1.1 |
pH 4 |
1 |
81.9 |
0.4 |
70.3 |
0.7 |
60.3 |
0.6 |
pH 4 |
10 |
9.0 |
0.8 |
3.3 |
0.6 |
2.3 |
0.5 |
pH 7 |
0 |
80.3 |
0.6 |
70.6 |
0.3 |
63.4 |
0.6 |
pH 7 |
1 |
81.3 |
0.7 |
69.9 |
0.0 |
62.0 |
0.5 |
pH 7 |
10 |
9.7 |
0.9 |
4.1 |
0.2 |
3.2 |
0.2 |
pH 9 |
0 |
93.8 |
0.6 |
90.0 |
1.3 |
86.7 |
1.6 |
pH 9 |
1 |
86.9 |
0.5 |
75.2 |
1.8 |
69.3 |
1.3 |
pH 9 |
10 |
10.6 |
0.2 |
5.9 |
0.3 |
4.5 |
0.4 |
The results showed that under NOM-free conditions, the pigment was minimally less stable.The differences are not statistically significant.
Table 2: Comparison of the results of the dispersion stability with and without the presence of NOM
sedimentation time |
6h |
24h |
1mM Ca, pH7, with NOM |
99.45±0.39 |
99.22 ± 0.05 |
1mM Ca, pH7, without NOM |
99.67 ± 0.02 |
98.81 ± 0.29 |
To rationalize the observed dispersion stability, the particle size distribution directly in the environmental medium (exact same sample preparation as for the UV/VIS measurements) was checked.
The NanoDefine method of Analytical Ultracentrifugation (SOP AUC-RI, published by 3) was applied. The centrifugation parameters are given above.
The observed size distributions confirm the low agglomeration at 0 mM and 1 mM Ca, against the high agglomeration at 10 mM Ca.
If the particles would have been significantly dissolved, no size distribution would be observable at all by this method, which relies on the detection of the movement of particles during centrifugal separation.
Additionally, the centrifugation methods include a determination of the remaining absorption after centrifugation, fully consistent with the conventional determination of the dissolved fraction after centrifugation as recommended by the TG-318. Even for the case of highest stability (pH 9, 0 mM Ca, with NOM), the remaining absorption was measured at 0.0504 ± 0.0024. This is a fraction of 2% of the initial absorption, but actually is close to the LOD of the built-in UV/Vis detector. Considering the LOD, between 0% and 2% of the sample may have been dissolved.
All evidence combined, the results after centrifugation confirm that at least 98% of the observed dispersion stability has to be attributed to the particles, not to dissolution.
Applicant's summary and conclusion
- Executive summary:
We found that the organic pigment is rather insensitive to pH changes, with little differences in dispersion stability between pH 4 and pH 9.
This is a significant difference against the metal oxide (TiO2) that was proposed as benchmark material of “intermediate stability” by the TG318.
Dissolution was excluded as the main cause of the apparent stability. The dispersion stability of Pigment Red 53:1 is of “intermediate stability” and depends especially on water hardness.
Only in very hard water with 10mM Ca, the stability of “low”. In all other conditions, the stability is at least “intermediate”, such that the aquatic compartment is relevant to risk assessment.
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