3,7-dimethyloctane-1,7-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

Study period:

24.10.2017 to 27.10.2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

2011

GLP compliance:

yes (incl. QA statement)

Remarks:

BioChem agrar, Labor für biologische und chemische Analytik GmbH, Kupferstr. 6, 04827 Machem OT Gerichshain (Germany)

Test material

Test material information

Constituent 1

Reference substance name:

3,7-dimethyloctane-1,7-diol

EC Number:

203-517-1

EC Name:

3,7-dimethyloctane-1,7-diol

Cas Number:

107-74-4

Molecular formula:

C10H22O2

IUPAC Name:

3,7-dimethyloctane-1,7-diol

Test material form:

liquid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Miltitz Aromatics GmbH (Bitterfeld-Wolfen, Germany), Batch No.: BM 7/17, Lot No.: 239/17
- Expiration date of the lot/batch: 14.06.2019
- Purity test date: 14.06.2017

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: hydroxycitronellol was stored in the original container, at room temperature (at BioChem agrar GmbH: at ca. 20°C, dark and dry)
- Stability under test conditions: yes

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: no
- Final dilution of a dissolved solid, stock liquid or gel: Due the water solubility of the test item ca. 30 g/L at 25°C), a stock solution was prepared. The desired test concentration of ca. 100 mg/L was achieved by dilution.

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

The test solution was prepared by weighing 100 mg test item into a flask and filling up to 1000 mL with test medium.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: green alga (Desmodesmus subspicatus
- Strain: 61.81 SAG
- Source (laboratory, culture collection): MBM ScienceBridge GmbH, Hans-Adolf-Krebs-Weg 1, 37077 Göttingen (Germany). The obtained culture was further cultivated at the test facility
- Age of inoculum (at test initiation): 4 d (cultures in logarithmic growth phase)
- Method of cultivation: Axenic stock cultures grew in culturing vessels for 4 d prior to test initiation. Cultivation was performed in glass flasks with the growth/test medium prepared according to guideline. Algae were kept at the same temperature and light conditions as in the test itself

ACCLIMATION: not necessary (cultivation and test conditions were the same)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

22.5-23.6°C

pH:

8.09-8.70 in all test vessels during the test

Nominal and measured concentrations:

0 (control), 100 mg/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flask
- Type (delete if not applicable): open (flasks equipped with air permeable stoppers)
- Material, size, headspace, fill volume: glass/250 ml/150 mL/100 mL
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): test conducted under static conditions
- Renewal rate of test solution (frequency/flow rate): test conducted under static conditions
- Initial cells density: 5 x 10E3 cells/mL
- Control end cells density: 2.8 x 10E5 cells/mL
- No. of vessels per concentration (replicates): 6 (+1 additioal vessel for analysis and retain specimen)
- No. of vessels per control (replicates): 6 (+1 additioal vessel for analysis and retain specimen)
- No. of vessels per vehicle control (replicates): no vehicle used

GROWTH MEDIUM
- Standard medium used: yes (according to guideline)

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to guideline
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Sterile test conditions: not reported
- Adjustment of pH: no
- Photoperiod: continuous lighting
- Light intensity and quality: 114 µE/m² x s (cold white fluorescent light)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : inhibition of growth and yield
- Determination of cell concentrations: microscope cell count using a Neubauer counting chamber

TEST CONCENTRATIONS
- Spacing factor for test concentrations: not applicable
- Justification for using less concentrations than requested by guideline: limit test
- Range finding study: performance not reported

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

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

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 3

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

Results with reference substance (positive control):

The 72 h EC50 values of average specific growth rate and yield determined in the most recent study were ErC50=1.38 mg/L test item for growth rate and EyC50=0.679 mg/L for yield. The ErC50 of 1.38 mg/L is included in the range of 1.19 mg/L +/-0.27 mg/L. The result indicates the sensitivity of the test system.

Reported statistics and error estimates:

The mean for the test concentration was compared with the control mean using Student's-t test. As a test for homogeneity of variances Levene's test was used. Statistical analysis was performed using the software ToxRat Professional.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In the 72 h algal growth inhibition test, the NOEC and the EC50 values for average specific growth rate and yield were determined to be >=100 mg/L and > 100 mg/L nominal, respectively.

Executive summary:

The toxicity of hydroxycitronellol to the green alga Desmodesmus subspicatus was investigated in a study conducted according to OECD Guideline 201 (Alga, Growth Inhibition Test; 2011). In this limit test, a culture of Desmodesmus subspicatus was exposed to a nominal concentration of 100 mg/L under static conditions for 72 h. The average specific growth rate and yield were recorded and the results statistically evaluated. The 72 h NOEC and EC50 for average specific growth rate and yield were determined to be >=100 mg/L and > 100 mg/L nominal, respectively.

The study is well documented and can be classified as reliable without restrictions satisfying the guideline requirements for a toxicity study with algae.

Results Synopsis

Test organism/age: Desmodesmus subspicatus (4 d old)

Test Type: static

Growth rate and yield
72 h NOEC: >=100 mg/L (nominal)

72 h EC50: >100 mg/L (nominal)

Endpoint(s) Effected: growth, yield