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EC number: 229-662-0 | CAS number: 6642-31-5
- 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
Toxicity to aquatic algae and cyanobacteria
Administrative data
Link to relevant study record(s)
- Endpoint:
- toxicity to aquatic algae and cyanobacteria
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 2002-04-26 - 2002-05-13 (experimental phase)
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 201 (Alga, Growth Inhibition Test)
- Version / remarks:
- OECD Guideline for Testing of Chemicals, No. 201: Alga, Growth Inhibition Test, 1984.
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- EU Method C.3 (Algal Inhibition test)
- Version / remarks:
- EU Commission Directive 92/69/EEC, C.3: Algal Inhibition Test, 1992
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Specific details on test material used for the study:
- STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature at about 20 °C, away from direct sunlight
- Stability under test conditions: Stability in water: Max. 90 days
OTHER SPECIFICS:
Solubility in water: 5.5 g/L
pH in aqueous solution: 7 - Analytical monitoring:
- yes
- Vehicle:
- no
- Details on test solutions:
- PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test medium of the only test concentration of nominal 100 mg/l was prepared by dissolving 31 mg test item completely in 300 ml test water by ultrasonic treatment for 15 minutes and intense stirring for 15 minutes at room temperature.
- Controls: A control was tested in parallel (test water without test item).
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): none stated - Test organisms (species):
- Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
- Details on test organisms:
- TEST ORGANISM
- Common name: green algae
- Strain: Scenedesmus subspicatus CHODAT, Strain No. 86.81 SAG
- Source (laboratory, culture collection): Supplied by the Sammlung von Algenkulturen Göttingen (SAG, Experimentelle Phykologie und Sammlung von Algenkulturen, Albrecht-von-Haller-lnstitut für Pflanzenwissenschaften, Universitat Göttingen, D-37073 Göttingen, Germany). The algae had been grown in the laboratories under standardized conditions according to the test guidelines.
- Age of inoculum (at test initiation): The test was started (0 hours) by inoculation of 10,000 algal cells per ml test medium. These cells were taken from an exponentially growing pre-culture, which was set up 3 days prior to the test under the same conditions as in the test.
- Method of cultivation:
The algae were cultivated and tested in synthetic test water, prepared according to the test guidelines. Analytical grade salts were dissolved in sterile purified water to obtain the following final nominal concentrations:
Macro-nutrients:
NaHCO3 50.0 mg/L
CaCl2 x 2 H2O 18.0 mg/L
NH4CI 15.0 mg/L
MgSO4 x 7 H2O 15.0 mg/L
MgCI2 x 6 H2O 12.0 mg/L
KH2PO4 1.6 mg/L
Trace elements:
Na2EDTA x 2 H2O 100.0 µg/L
FeCI3 x 6 H2O 80.0 µg/L
MnCl2 x 4 H2O 415.0 µg/L
H3BO3 185.0 µg/L
Na2MoO4 x 2 H2O 7.0 µg/L
ZnCI2 3.0 µg/L
CoCl2 x 6 H2O 1.5 µg/L
CuCI2 x 2 H2O 0.01 µg/L - Test type:
- static
- Water media type:
- freshwater
- Limit test:
- yes
- Total exposure duration:
- 72 h
- Post exposure observation period:
- none
- Hardness:
- Calculated water hardness of the test water: 0.24 mmol/l (=24 mg/l) as CaCO3
- Test temperature:
- Algae were incubated in a temperature controlled water bath at a temperature between 22 and 23 °C
- pH:
- At the start of the test, the pH value in the test medium and the control was 8.0. At the end of the test, pH value of 9.0 was measured.
- Nominal and measured concentrations:
- 0, 100 mg/l (nominal)
- Details on test conditions:
- TEST SYSTEM
- Test vessel: flasks
- Type (delete if not applicable): The flasks were covered with glass dishes.
- Material, size, headspace, fill volume: Volumes of 15 ml algal suspension for each replicate were continuously stirred by magnetic stirrers in 50 mL Erlenmeyer flasks,
- Renewal rate of test solution (frequency/flow rate): none
- Initial cells density: 10,000 algal cells per ml test medium
- Control end cells density: 76.18 x 10,000 cells/ml (72h)
- No. of vessels per concentration (replicates): three replicates per test concentration
- No. of vessels per control (replicates): six replicates of the control
GROWTH MEDIUM
- Standard medium used: yes
TEST MEDIUM / WATER PARAMETERS
- Culture medium different from test medium: no
- Intervals of water quality measurement: The pH was measured and recorded in the single test concentration and the control at the start and at the end of the test. The water temperature was measured and recorded daily in an Erlenmeyer flask filled with water and incubated under the same conditions as the test flasks. The appearance of the test medium was recorded daily.
OTHER TEST CONDITIONS
- Adjustment of pH: not stated
- Photoperiod: continuously illuminated
- Light intensity and quality: measured light intensity of about 8700 Lux (mean value), range: 8000 to 9200 Lux (minimum and maximum value of measurements at 9 places distributed over the experimental area at the surface of the test medium). This illumination was achieved by fluorescent tubes (Philips TLD 36W/840), installed above the test flasks.
EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Small volumes of the test medium and the control (1.0 ml) were taken out of all test flasks after 24, 48 and 72 hours exposure, and were not replaced. The algal cell densities in the samples were determined by counting with an electronic particle counter (Coulter Counter®, Model ZM), with at least two measurements per sample.
In addition, after 72 hours exposure, a sample was taken from the control and from the single test concentration (nominal 100 mg/L). The shape of the algal cells was microscopically examined in these samples.
TEST CONCENTRATIONS
- Justification for using less concentrations than requested by guideline: The test concentration was based on the results of a range-finding test (without GLP).
- Test concentrations: 0, 100 mg/l - Reference substance (positive control):
- yes
- Remarks:
- For evaluation of the algal quality and experimental conditions, potassium dichromate is tested as a positive control at least once per year to demonstrate satisfactory test conditions.
- Key result
- Duration:
- 72 h
- Dose descriptor:
- NOEC
- Effect conc.:
- >= 100 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Duration:
- 72 h
- Dose descriptor:
- NOEC
- Effect conc.:
- >= 100 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- biomass
- Key result
- Duration:
- 72 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 100 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Duration:
- 72 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 100 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- biomass
- Details on results:
- - Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no abnormalities stated
- Any stimulation of growth found in any treatment: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: none - Results with reference substance (positive control):
- not stated
- Validity criteria fulfilled:
- yes
- Conclusions:
- The test was performed scientifically reasonable according to OECD 201 under GLP, the report is well documented and the validity criteria are met. Hence, the results can be considered as sufficiently reliable to assess the toxicity of 1,3-Dimethyl-4-aminouracil to algae.
The mean biomass and growth rate of the algae grown at the test concentration of 100 mg/l were inhibited by only 10 and 3.9% respectively. This low inhibition was not considered to be of a biological relevance. This is also confirmed by the 72-hour results of the range-finder test, where the mean algal cell density in the test medium of 100 mg/l was even slightly higher compared to the control value. The 72-hour LOEC (lowest concentration tested with toxic effects), and the 72-hour EC50 for the algal biomass b and growth rate r could not be quantified due to the absence of a toxic effect of 1,3-DimethyI-4-aminouracil at the tested concentration. However, these parameters were clearly higher than 100 mg/L.
With an ErC50 > 100 mg/l, 1,3-Dimethyl-4-aminouracil does not need to be classified as hazardous to the environment acc. Regulation 1272/2008, neither acute nor chronic. - Executive summary:
The influence of the test item 1,3-Dimethyl-4-aminouracil on the growth of the green algal species Scenedesmus subspicatus CHODAT was investigated in a 72-hour static test according to the EU Commission Directive 92/69/EEC, C.3, 1992, and the OECD Guideline No. 201, 1984, under GLP.
A limit test was performed in accordance with the EU Commission Directive 92/69/EEC to demonstrate that the test item has no toxic effect on Scenedesmus subspicatus up to and including the concentration of nominal 100 mg/l. Thus the only concentration tested was nominal 100 mg/l and a control.
The analytically determined test item concentration in the analyzed test medium was 104 and 103% of the nominal value at the start and the end of the test. Consequently, the test item was stable during the test period of 72 hours under the test conditions, and the reported biological results are based on the nominal concentration of the test item.
The test item 1,3-Dimethyl-4-aminouracil had no significant inhibitory effect on the growth of Scenedesmus subspicatus during the exposure period of 72 hours at the test concentration of 100 mg/l. The 72-hour NOEC (highest concentration tested without toxic effects after the exposure period of 72 hours) of 1,3-Dimethyl-4-aminouracil to Scenedesmus subspicatus was determined to be at least 100 mg/l. Concentrations in excess of 100 mg/l have not been tested, according to EU Commission Directive 92/69/EEC.
The 72-hour EC50 and the 72-hour EC100 were clearly higher than 100 mg/L. These values could not be quantified due to the absence of toxicity of 1,3-Dimeihyl-4-aminouracil up to the tested concentration.
1,3-Dimethyl-4-aminouracil does not need to be classified as hazardous to the environment acc. Regulation 1272/2008, neither acute nor chronic.
- Endpoint:
- toxicity to aquatic algae and cyanobacteria
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: GLP, Guideline Study. Scientifically acceptable.
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 201 (Alga, Growth Inhibition Test)
- GLP compliance:
- yes
- Analytical monitoring:
- yes
- Details on test solutions:
- A stock solution (125 mg/l, nominal) was prepared using deionized water and was then treated ultrasonically for 3 minutes. Following this, the stock solution was stirred for about 10 min at approximately 20 +/- 2 °C. Serial dilutions of this stock solution were subsequently made in order to obtain the desired test concentrations.
- Test organisms (species):
- Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
- Details on test organisms:
- TEST ORGANISM
- Strain: strain SAG 86.81
- Source (laboratory, culture collection): University of Goettingen - Test type:
- static
- Water media type:
- freshwater
- Limit test:
- no
- Total exposure duration:
- 72 h
- Test temperature:
- 23 +/- 2 °C
- Nominal and measured concentrations:
- Nominal test concentrations: 1.56. 3.13, 6.25, 12.5, 25.0, 50.0, 100.0 mg/l Additionally, a culture medium control was tested in parallel.
- Details on test conditions:
- TEST SYSTEM
- Test vessel: Erlenmeyer flasks (nominal volume 250 ml) plugged with gas permeable siliconsponge caps
- Material, size, headspace, fill volume:
- Initial cells density: 10000
- Control end cells density:
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
GROWTH MEDIUM
- Standard medium used: yes/no
- Detailed composition if non-standard medium was used:
TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to OECD guideline 201.
OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Adjustment of pH:
- Photoperiod: 16:8 h day-night regime
- Light intensity and quality: artificial light, type universal white, permanent illumination, about 60 - 120 microE/(m2*s) at a wave length of 400 - 700 nm
- Salinity (for marine algae):
EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: in vivo chlorophyll-a-fluorescence (pulsed excitation with light flashes having a wavelength of 435 nm), after 72 h in a counting chamber (Neubauer improved) in replicate No. 2 of the inoculated control - Duration:
- 72 h
- Dose descriptor:
- EC10
- Effect conc.:
- > 100 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Key result
- Duration:
- 72 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 100 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Reported statistics and error estimates:
- The EC50 was determined directly from the raw data.
Referenceopen allclose all
Effect on the development of biomass:
EbC10 (72 h) = 91.1 mg/l
EbC50 (72 h) > 100 mg/l
No observed effect concentration (95 % significance level)
NOEbC (72 h) = 50 mg/l
NOErC (72 h) = 6.25 mg/l
Lowest observed effect concentration (95 % significance level)
LOEbC (72 h) = 100 mg/l
LOErC (72 h) = 12.5 mg/l
Chemical analysis:
Analytical recovery rates (control analyses of 1.56, 12.5 and 100 mg/l):
after 0 h = 92.9 - 97.6 %
after 72 h = 100 - 107.2 %
Description of key information
Toxicity to aquatic algae
- ErC50 > 100 mg/l, ErC0 ≥ 100 mg/l for Desmodesmus subspicatus over 72h (OECD 201, static, GLP)
- ErC50 > 100 mg/l, ErC0 ≥ 100 mg/l, NOEC = 100 mg/l for Desmodesmus subspicatus over 72h (OECD 201, static, GLP)
Key value for chemical safety assessment
- EC50 for freshwater algae:
- 100 mg/L
- EC10 or NOEC for freshwater algae:
- 100 mg/L
Additional information
According to Regulation 1272/2008, Table 4.1.0, Classification categories for hazardous to the aquatic environment, a substance must be classified as Acute (short-term) aquatic hazard, Acute Category 1, if i.a. the 72 or 96 hr ErC50 (for algae or other aquatic plants) is ≤ 1 mg/l. It must be classified as Chronic Category 3 if the 72 or 96 hr ErC50 (for algae or other aquatic plants) is > 10 to ≤ 100 mg/l, and the substance is not rapidly degradable and/or the experimentally determined BCF ≥ 500 (or, if absent, the log Kow ≥ 4).
In both available studies, the following values were determined: ErC50 > 100 mg/l, EC0/NOEC ≥ 100 mg/l, for Desmodesmus subspicatus. Hence, the substance does not need to be classified as hazardous to the aquatic environment, neither acute nor chronic.
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