3-methyl-1,3-butandiol

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23 May 2005 - 15 July 2005

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:

On day 2 of the definitive test, the maximum temperature in the incubator was 25.1°C, which is
slightly above that stated in the study protocol (25°C).

Deviations:

yes

Remarks:

As the validity criteria for this type of study were met this is not considered to have affected the integrity or validity of the study.

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

On day 2 of the definitive test, the maximum temperature in the incubator was 25.1°C, which is
slightly above that stated in the study protocol (25°C).

Deviations:

yes

Remarks:

As the validity criteria for this type of study were met this is not considered to have affected the integrity or validity of the study.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Appearance: Clear, colourless liquid
Storage conditions: Room temperature in the dark
Batch number: 52834
Expiry date: December 2006
Purity: 99%

Analytical monitoring:

yes

Details on sampling:

For samples whose nominal concentration of the test item was greater than 25 mg/l, the aqueous samples were diluted with methanol (1 ml to 20 ml) to bring the expected concentration within the calibration range.
For samples whose nominal concentration of the test item was less than 25 mg/l, the aqueous samples were partially evaporated and then diluted with methanol (1 ml to 20 ml) to bring the expected concentration within the calibration range.

Vehicle:

no

Details on test solutions:

Identity and concentration of auxiliary solvent for dispersal: The test media were prepared from aqueous dilution in which the test substance was added directely to algal culture medium. If further dilution was required, sterile culture medium was used.

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name: Selenastrum capricornutum
- Strain: CCAP 278/4
- Age of inoculum (at test initiation): three days
- Method of cultivation: Sterile algal nutrient medium

ACCLIMATION
- Culturing media and conditions (same as test or not): yes

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

24.2 ± 0.9°C

pH:

7.80 - 10.30

Nominal and measured concentrations:

Nominal concentrations: 4.27, 9.39, 20.7, 45.5 & 100 mg/l
Mesured concentations: 3.45, 7.97, 16.0, 45.2, 95.8 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: Conical flasks
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: Conical flasks (250 ml)
- Initial cells density: 1 x 10^4 cells/ml (nominal)
- Control end cells density: 1 x 10^4 cells/ml (nominal)
- No. of organisms per vessel: 1 x 10^4 cells/ml (nominal)
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 5

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod: continuous illumination
- Light intensity and quality: 6158 lux provided by “cool white”

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: haemacytometer
- Other: The presence of any abnormal cells

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 1, 10 and 100 mg/l
- Results used to determine the conditions for the definitive study:The results of this test indicated that the test substance inhibited the growth of Selenastrum by 42% compared to the control group when prepared at a nominal concentration of 100 mg/l.

Reference substance (positive control):

yes

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 95.8 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

not determinable

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 95.8 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

not determinable

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 95.8 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 95.8 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

The measurements of water quality (temperature and pH) in control and test flasks remained within acceptable limits throughout the study.

Results with reference substance (positive control):

The results of the most recent laboratory reference test using potassium dichromate indicated that its 72-hour EbC50 to Selenastrum capricornutum was 0.92 mg/l; this was within the range typically obtained in this laboratory (0.3 to 1 mg/l).

Validity criteria fulfilled:

yes

Conclusions:

After 72 hours of exposure to the test item, the EbC50 and ErC50, could not be determined but must be > 95.8 mg/l.
The “no observed effect concentration” (NOEC) was >95.8 mg/l.

Description of key information

After 72 hours of exposure to the test item, the EbC50 and ErC50, could not be determined but must be > 95.8 mg/l.

The “no observed effect concentration” (NOEC) was >= 95.8 mg/l.

Key value for chemical safety assessment

EC50 for freshwater algae:

95.8 mg/L

EC10 or NOEC for freshwater algae:

95.8 mg/L