2,5-dimethylhexane-2,5-diol

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study without restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2,5-dimethylhexane-2,5-diol

EC Number:

203-731-5

EC Name:

2,5-dimethylhexane-2,5-diol

Cas Number:

110-03-2

Molecular formula:

C8H18O2

IUPAC Name:

2,5-dimethylhexane-2,5-diol

Test material form:

other: solid pastilles

Details on test material:

- Name of test substance: 2,5-dimethylhexane-2,5-diol
- Test substance No.:
- Batch identification: Charge 35130868E0
- CAS No.: 110-03-2
- purity: 99%

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:The stock solution (355 mg/L) was prepared by directly adding 710.15 mg of test substance to 2L of test medium (AAP-medium) and stirring for approximately 10 min until visibly dissolved. The stock solution was prepared at 111% of the nominal concentration to compensate for the dilution by the later addition of algal inoculum. The lower test concentrations were prepared by dilution of this stock solution. Before the dilution was performed, the stock solution was checked for complete dissolution of the test substance.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no

Test organisms

Test organisms (species):

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

Details on test organisms:

-Test species and strain: Pseudokirchneriella subcapitata KORSHIKOV (SAG 61.81)
- Age (on study day 0):A stock algal culture is maintained continuously at the test facility. Before the exposure an inoculum culture is prepared from the stock culture and incubated for 4 days at 21 – 24 °C (max. temperature difference 2 °C). After this time, the inoculum culture is in exponential growth phase and can be used to initiate the test (study day 0).
- Supplier: Collection of algal cultures in University of Göttingen/Germany

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

pH:

7.1-8.6

Nominal and measured concentrations:

3.2, 10, 32, 100 and 320 mg/L (nominal, verfied analytically)

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: Erlenmeyer flasks (nominal volume 250 mL) plugged with gas permeable silicone sponge caps, 100 ml fill volume
- Initial cells density: 0.5 x 10E-04 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6


GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16:8
- Light intensity and quality: Average 6776 lux (within ±15% variability) at a wave length of 400 - 700 nm

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Nominal concentrations verified analytically

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Nominal concentrations verified analytically

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

With high probability not harmfull to aquatic algae.