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EC number: 214-772-3 | CAS number: 1193-24-4
- 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
Short-term toxicity to aquatic invertebrates
Administrative data
Link to relevant study record(s)
- Endpoint:
- short-term toxicity to aquatic invertebrates
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 1996-01-31 to 1996-03-04
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Valid and conclusive study under GLP , similar to guideline but deficiencies in reporting and no analytical dose verification
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- EU Method C.2 (Acute Toxicity for Daphnia)
- Version / remarks:
- 92/69/EWG
- Deviations:
- no
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
- Version / remarks:
- 1984
- Deviations:
- no
- GLP compliance:
- yes
- Analytical monitoring:
- yes
- Vehicle:
- no
- Details on test solutions:
- PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test item was dissolved in synthetic freshwater.
- Concentration of vehicle in test medium (stock solution and final test solution): stock solution: 1 g/L, final test solutions: 60, 100, 170, 300, 500, 900 mg/L - Test organisms (species):
- Daphnia magna
- Details on test organisms:
- TEST ORGANISM
- Strain: clone 5
- Source: in-house breeding
- Age at study initiation (mean and range, SD): < 24h
- Method of breeding: in 1L beakers in M4 medium, feeding with alge (Scenedesmus subspicatus) daily - Test type:
- static
- Water media type:
- freshwater
- Limit test:
- no
- Total exposure duration:
- 48 h
- Post exposure observation period:
- No post-observation performed
- Test temperature:
- 20 ± 1°C
- pH:
- 4.3-7.7, dependent on concentration of the test item which shows acidic behavior.
- Dissolved oxygen:
- 7.8-8.1 mg/L
- Nominal and measured concentrations:
- nominal concentrations: 60, 100, 170, 300, 500, 900 mg/L
No analytical determination of test item concentrations were performed during the test. - Details on test conditions:
- TEST SYSTEM
- Test vessel: round-bottom glasses
- Material, size, headspace, fill volume: glass, fill volume 10 mL
- Aeration: none
- No. of organisms per vessel: 5 animals/vessel
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: 1 animal per 2 mL
TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: synthetic freshwater: CaCl2*2 H2O: 294 mg/L, MgSO4*7H2O: 123 mg/L, NaHCO3: 63 mg/L, KCl: 5.5 mg/L
- Ca/Mg ratio: 4:1
- Culture medium different from test medium: yes
OTHER TEST CONDITIONS
- Adjustment of pH: not specified
- Photoperiod: not specified
- Light intensity: not specified
EFFECT PARAMETERS MEASURED: immobilisation
TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.67-1.8
- Test concentrations: nominal concentrations: 60, 100, 170, 300, 500, 900 mg/L - Reference substance (positive control):
- yes
- Remarks:
- potassium dichromate (CAS 7778-50-9 )
- Duration:
- 48 h
- Dose descriptor:
- EC50
- Effect conc.:
- 104 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- mobility
- Remarks on result:
- other: 95% CL: 83-130
- Duration:
- 48 h
- Dose descriptor:
- EC100
- Effect conc.:
- 300 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- mobility
- Duration:
- 24 h
- Dose descriptor:
- EC50
- Effect conc.:
- 168 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- mobility
- Remarks on result:
- other: 95% CL: 123 - 230
- Duration:
- 48 h
- Dose descriptor:
- EC10
- Effect conc.:
- > 60 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- mobility
- Remarks on result:
- other: 5% immobility at 60 mg/L
- Details on results:
- Results are displayed in table 2.
The EC50 value after 48h incubation, based on immobilisation, is 104 mg/L. The highest concentration at which no immobilisation (< 10%) was observed was 60 mg/L. - Results with reference substance (positive control):
- For potassium chromate, the following results were determined after 24h incubation:
concentration 1 mg/L: 25% immobilisation
concentration 2 mg/L: 100% immobilisation
Assuming linear dose-response, the 24h EC50 can be determined from these two measurements to be 1.33 mg/L. As this is in the required EC50 range of 0.6-2.1 mg/L for potassium dichromate, the test system is valid. - Validity criteria fulfilled:
- yes
- Conclusions:
- The test item 4,6-dihydroxypyrimidin (CAS 1193-24-4) was found not acute toxic to daphnids.
- Executive summary:
Acute aquatic toxicity of 4,6-dihydroxypyrimidin (CAS 1193-24-4) was tested under GLP with an Daphnia immobilisation assay similar to EU Method C.2 and OECD Guideline 202. Briefly, daphnids (4 replicas with 5 animals each per concentration) were incubated with the test item dissolved in freshwater. After 24 and 48 h the number of immobile daphnids were counted. The concentrations tested were 60, 100, 170, 300, 500, and 900 mg/L (nominal concentrations). No analytical verification of test item concentrations was performed during the test but stability was assessed in a pre-test over 72 h without daphnia.
The test item 4.6-dihydroxypyrimidine caused distinct immobilisation of daphnids with clear concentration-response data. The 48 h EC50 was 104 mg/L.
Reference
Table 2: Cumulated number of immobilized daphnia after incubation with the test item 4,6-dihydroxypyrimidine
Concentration [mg/L] |
after 24 h |
after 48 h |
||||
number |
% immobile |
number |
% immobile |
|||
mobile |
immobile |
mobile |
immobile |
|||
0 (control) |
20 |
0 |
0 |
20 |
0 |
0 |
60 |
19 |
1 |
5 |
19 |
1 |
5 |
100 |
13 |
7 |
35 |
10 |
10 |
50 |
170 |
9 |
11 |
55 |
2 |
18 |
90 |
300 |
8 |
12 |
60 |
0 |
20 |
100 |
500 |
0 |
20 |
100 |
0 |
20 |
100 |
900 |
0 |
20 |
100 |
0 |
20 |
100 |
Description of key information
EC50 = 104 mg/L, 48h, Daphnia Magna, similar to EU Method C.2 and OECD Guideline 202, Scholz 1996
Key value for chemical safety assessment
Fresh water invertebrates
Fresh water invertebrates
- Effect concentration:
- 104 mg/L
Additional information
The study report for the determination of the Acute Toxicity to Daphnia magna conducted under GLP (Scholz 1996) shows deficiencies in reporting and no analytical dose verification, however it is considered to be relevant and adequate for the purposes of risk assessment, classification and labeling.
Several other studies were available from the literature, but none were suitable for regulatory use.
In the Kaiser et al (2001) publication, four QSAR models for the acute toxicity (as LC50 value) of chemicals to daphnids (Daphnia magna) using probabilistic neural networks were developed and reported, however not all validity criteria for regulatory purposes were met. Thus the estimation method is scientifically invalid and not usable for regulatory purposes.
In the context of the Kaiser et al (2001) publication, reference values taken from the TerraTox database (http://www.terrabase-inc.com/) were cited. The publication gives no information for the original source of this value but it is possibly that measured by Chen et al (1996 & 1997). It should be noted that Chen at al (1996 & 1997) tested according to APHA (American Public Health Association) standards, where EC50 rather than LC50 is measured, immobility is considered without agitation of the test vessel.
In the Chen (1996 & 1997) publication, the effect of 24 h exposure of no further specified daphnids (Daphnia sp.) to 4,6-dihydroxypyrimidine was tested according to American Public Health Association (1985) standards. The authors use the results for QSAR considerations in two different publications (1996 & 1997). However the validity criteria of the method used has significant methodological deficiencies compared to current standards (no standardized test animals, different effect definition for immobility, and evaluation after 24 h) and the detail level of the documentation is poor. A daphnid was counted as immobile when it swam a distance less than its length in 15 s without foregoing agitation of the test vessel as required by OECD 202 (2004). Consequently, the EC50 may be determined to be at a lower concentration compared to the OECD standard and accordingly the results are considered not reliable and discarded.
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