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EC number: 203-308-5 | CAS number: 105-55-5
- 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:
- Experimental start: 26/04/11 - Experimental end: 19/05/11
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: 1a: OECD guideline study performed according GLP criteria.
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 201 (Alga, Growth Inhibition Test)
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Specific details on test material used for the study:
- Details on properties of test surrogate or analogue material (migrated information):
No test surrogate or analogue material was used. - Analytical monitoring:
- yes
- Details on sampling:
- Test flasks and blanks were prepared in triplicate. Six replicates were used for the control.
After 24, 48 and 72 h of incubation, about 1 mL was sampled from each test flask. - Vehicle:
- no
- Details on test solutions:
- As the test item is soluble in water, stock solutions were prepared the day the test was started.
For the range-finding test a stock solution at 100 mg/L was prepared by weighing 100 mg of test item in 1 liter of dilution water. This stock solution was diluted in order to obtain the convenient range of nominal concentrations: 0.1, 0.5, 1, 5, 10, 50 and 100 mg/L.
For the definitive test, a stock solution at 500 mg/L was prepared by weighing 2 g of test item in 2 liters of dilution water. This stock solution was diluted in order to obtain the convenient range of concentrations: 50, 73, 107, 157, 231, 340 and 500 mg/L. - Test organisms (species):
- Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)
- Details on test organisms:
- Pseudokirchneriella subcapitata, CCAP 278/4 stock (previously named Raphidocelis subcapitata and Selenastrum capricornutum) are obtained from the Culture Centre of Algae and Protozoa (Ambleside, UK).
Two flasks, each containing approximately 100 mL of axenic stock culture of algae are incubated at 23 ± 1 °C under lighting (photoperiod: 16 hours of illumination, 8 hours of darkness), slowly continuously shaken. These stock cultures are renewed every week, using two new cultures.
The quality of the stock culture was verified for the absence of micro-organisms and deformed cells under microscopic observation before use.
Three days before the beginning of the study two pre-cultures were prepared by inoculating each stock suspension of algae (5 mL) into sterile dilution water (500 mL). The pre-cultures were incubated under the same conditions as those used for the stock cultures. Only one of the two pre-cultures was used to inoculate the test flasks; the second one was to be used only if the first one was damaged.
At the beginning of the test, the cell concentration of the pre-culture was determined. The result was used to calculate the volume to be introduced into each test flask in order to get an initial cell concentration of 104 cells/mL.
The cell density of the pre-culture was about 2.49 x 106 cells/ml for the preliminary test and about 2.39 x 106 cells/ml for the definitive test. - Test type:
- static
- Water media type:
- freshwater
- Limit test:
- no
- Total exposure duration:
- 72 h
- Post exposure observation period:
- No post-exposure observation period was done.
- Test temperature:
- 23°C +/- 1°C
- pH:
- See "Any other information on material and methods incl. tables"
- Dissolved oxygen:
- See "Any other information on material and methods incl. tables"
- Salinity:
- Test was performed in freshwater.
- Nominal and measured concentrations:
- For the definitive test, a stock solution at 500 mg/L was prepared by weighing 2 g of test item in 2 liters of dilution water. This stock solution was diluted in order to obtain the convenient range of concentrations: 50, 73, 107, 157, 231, 340 and 500 mg/L.
- Details on test conditions:
- The incubation was performed in a phytoculture cabinet that allows test flasks to be incubated under precise conditions: temperature was set to 23 ± 1°C; flasks were continuously shaken with a rotation at 20 rpm and constantly illuminated by 8 fluorescent tubes between 6,000 and 10,000 lux (Mazdafluor, white industry 33). The study was performed using 120 mL glass bottles stoppered with cellulose bungs. Filling volume: 50 mL.
Test flasks and blanks were prepared in triplicate. Six replicates were used for the control.
After 24, 48 and 72 h of incubation, about 1 mL was sampled from each test flask. After 24 and 48 hours test flasks were replaced in the same position in the rotary shaker. Samples were stored in darkness until determination of algae concentration by cell counter cell. Measured concentrations of algae were used for calculating the percentages inhibition and plotting the growth curves.
The pH and dissolved O2 were measured for all concentrations, at the beginning and the end of the test. - Reference substance (positive control):
- yes
- Remarks:
- Potassium dichromate
- Duration:
- 72 h
- Dose descriptor:
- EC50
- Effect conc.:
- 310 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Remarks on result:
- other: 230 - 470
- Duration:
- 72 h
- Dose descriptor:
- EC50
- Effect conc.:
- 200 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Basis for effect:
- biomass
- Remarks on result:
- other: 150 - 270
- Duration:
- 72 h
- Dose descriptor:
- NOEC
- Effect conc.:
- 73 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Details on results:
- The appearance of the test solutions was visually checked at the beginning and at the end of the test. Solutions were found to be clear, colourless over the period of the test. No precipitation was observed at the end of the test.
Microscopic observation confirmed that the algae appeared normal at the end of the test: the normal shape of P. subcapitata algae is a crescent shaped cell with an average length of 5-10 µm. - Results with reference substance (positive control):
- The sensitivity of the test system and the methodology are evaluated every two months by performing an algal growth inhibition test on potassium dichromate. The nearest values of ErC50 and EbC50 obtained on 31/03/11 were respectively 1.10 mg/L and 0.67 mg/L.
For information, ISO 8692 reports the following results for an inter-laboratory exercise on potassium dichromate: ErC50: 0.60 to 1.03 mg/L EbC50: 0.20 to 0.75 mg/L. - Validity criteria fulfilled:
- yes
- Remarks:
- See "Overall remarks"
- Conclusions:
- The determination of the growth inhibition of the freshwater algae Pseudokirchneriella subcapitata (previously known as Raphidocelis subcapitata and Selenastrum capricornutum) exposed to the test item1,3 – Diethyl-2-thiourea for a duration of 72 hours was assessed according to the OECD Guideline 201.
Algae were exposed to 500 to 50 mg/L 1,3 – Diethyl-2-thiourea dissolved in dilution water. The toxic effect measured during the assay was the inhibition of cellular multiplication over a time period of 72 hours.
The concentrations of test item causing a 50 % reduction in biomass (EbC50) and in growth rate (ErC50) were estimated respectively at 200 (150-270) and 310 (230-470) mg/l. - Executive summary:
The determination of the growth inhibition of the freshwater algae Pseudokirchneriella subcapitata (previously known as Raphidocelis subcapitata and Selenastrum capricornutum) exposed to the test item 1,3 – Diethyl-2-thiourea for a duration of 72 hours was assessed according to the OECD Guideline 201.
Algae were exposed to 500 to 50 mg/L 1,3 – Diethyl-2-thiourea dissolved in dilution water. The toxic effect measured during the assay was the inhibition of cellular multiplication over a time period of 72 hours.
The concentrations of test item causing a 50 % reduction in biomass (EbC50) and in growth rate (ErC50) were estimated. It was possible to determine No Observable Effect Concentrations (NOEC). The results were as follows:
Endpoint
EC50-72h, mg/L (95% CI)
NOEC, mg/L
Cell growth – Biomass (b)
200 (150 – 270)
73
Growth rate – Cell multiplication (r)
310 (230 – 470)
73
CI: confidence interval
Reference
Average cell densities, biomass (A) and growth rates (µ)
Concentration (nominal)
|
Average cell density (cell/mL) |
||||||||||||
mg/L |
T0 |
T24h |
T48h |
T72h |
A |
µ |
|||||||
0 (T) |
1,00E+04 |
2,61E+04 |
1,21E+05 |
5,16E+05 |
52 |
1,315 |
|||||||
500 |
1,00E+04 | 1,68E+04 |
2,68E+04 | 2,95E+04 |
3 | 0,361 |
|||||||
340 |
1,00E+04 | 2,22E+04 |
3,34E+04 | 7,24E+04 |
7 | 0,660 |
|||||||
231 |
1,00E+04 | 2,62E+04 |
7,61E+04 | 1,29E+05 |
13 | 0,853 |
|||||||
157 |
1,00E+04 | 2,53E+04 |
1,04E+05 | 1,69E+05 |
17 | 0,943 |
|||||||
107 |
1,00E+04 | 2,74E+04 |
1,31E+05 | 3,15E+05 |
31 | 1,150 |
|||||||
73 |
1,00E+04 | 3,09E+04 |
1,50E+05 | 5,68E+05 |
57 | 1,346 |
|||||||
50 |
1,00E+04 | 2,74E+04 |
1,19E+05 | 5,39E+05 |
54 | 1,329 |
The biomass in the control cultures increased exponentially by a factor of 52 (corresponding to a specific growth rate of 1.315 day-1) within the 72-hour test period,which is higher than the minimal value (R = 16) mentioned OECD guideline 201.
Definitive test - Average percentage inhibition of cell growth (IAi) and growth rate (Iµi)
Concentration (nominal) |
IAi |
Iµi |
(mg/L) |
(%) |
(%) |
0 (T) |
0,00 |
0,00 |
500 |
91,20 |
72,55 |
340 |
82,41 |
49,81 |
231 |
62,66 |
35,15 |
157 |
50,27 |
28,27 |
107 |
23,36 |
12,56 |
73 |
-15,80 |
-2,41 |
50 |
-3,01 |
-1,10 |
Nominal and measured concentrations of the test itemat the beginning and at the end ofthe exposure period
Concentrations ofN,N’- DIETHYL THIOUREA
|
|||
Nominal Concentration |
Measured in non inoculated solutions |
||
|
Initial |
Final |
Final/Initial |
(mg/L) |
(mg/L) |
(mg/L) |
% |
0 |
< DL |
< DL |
- |
500 |
501 |
502 |
100.2 |
340 |
351 |
365 |
104.0 |
231 |
257 |
251 |
97.7 |
157 |
168 |
174 |
103.6 |
107 |
121 |
119 |
98.3 |
73 |
83 |
85 |
102.4 |
50 |
58 |
58 |
100 |
< DL : concentration lower than the Detection Limit of the analytical method (0.16 mg/L).
< QL : concentration lower than the Quantification Limit of the analytical method (0.55 mg/LDescription of key information
The determination of the growth inhibition of the freshwater algae Pseudokirchneriella subcapitata exposed to the test item 1,3 – Diethyl-2-thiourea for a duration of 72 hours was assessed according to the OECD Guideline 201 and GLP requirements. ErC50 was determined: ErC50-72h=310 mg/L
Key value for chemical safety assessment
- EC50 for freshwater algae:
- 310 mg/L
- EC10 or NOEC for freshwater algae:
- 73 mg/L
Additional information
The determination of the growth inhibition of the freshwater algae Pseudokirchneriella subcapitata (previously known as Raphidocelis subcapitata and Selenastrum capricornutum) exposed to the test item 1,3 – Diethyl-2-thiourea for a duration of 72 hours was assessed according to the OECD Guideline 201.
Algae were exposed to 500 to 50 mg/L 1,3 – Diethyl-2-thiourea dissolved in dilution water. The toxic effect measured during the assay was the inhibition of cellular multiplication over a time period of 72 hours.
The concentrations of test item causing a 50 % reduction in biomass (EbC50) and in growth rate (ErC50) were estimated. It was possible to determine No Observable Effect Concentrations (NOEC). The results were as follows:
Endpoint |
EC50-72h, mg/L (95% CI) |
NOEC, mg/L |
Cell growth – Biomass (b)
|
200 (150 – 270) |
73 |
Growth rate – Cell multiplication (r)
|
310 (230 – 470) |
73 |
CI: confidence intreval
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