Registration Dossier

Ecotoxicological information

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

Constituent 1
Chemical structure
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 concentrationsopen allclose all
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
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
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