Dioctadecyl ether

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: OECD 202 study with GLP, all validity criteria fulfilled.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Dioctadecyl ether

EC Number:

228-567-1

EC Name:

Dioctadecyl ether

Cas Number:

6297-03-6

Molecular formula:

C36H74O

IUPAC Name:

1-(octadecyloxy)octadecane

Test material form:

not specified

Details on test material:

- Name of test material (as cited in study report): Dioctadecyl ether
- Physical state: odorless yellowish solid
- Analytical purity: 85 %
- Impurities (identity and concentrations): Stearyl alcohol, max. 15 %
- Lot/batch No.: CD11380005

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: 0.1000 g test item were mixed with 1000 mL Algal Medium 4 in a 1000 mL measuring flask, resulting in a concentration of 100.0 mg test item/L. This stock solution was stirred for 72 hours at room temperature in the dark, and filtered thereafter, using a glass fibre filter (average retention capacity: 0.4 1-1m) to achieve the soluble fraction of the test item (water soluble fraction, WSF) at a loading rate of 100 mg test item/L. The concentration in the stock/application solution was identical to the concentration in the test solution and was used to prepare the Iimit test item concentration Ievel.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): The filtrate was visually checked for un-dissolved particles by the Tyndall-effect and microscopically, and no particles were observed.

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Strain: SAG 61.81
- Source (laboratory, culture collection): obtained from University of Göttingen ( Sammlung von Algenkulturen, Pflanzenphysiologisches Institut), Göttingen, Germany
- Age of inoculum (at test initiation): The test algae are taken from a 3 days old continuously growing preculture.
- Method of cultivation: The test strain is kept in liquid culture in the laboratory.

ACCLIMATION
- Acclimation period: 3 days
- Culturing media and conditions (same as test or not): same as test medium

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

22.0 - 23.1 °C

pH:

start of test: 6.0 - 6.1
end of test: 6.1 - 6.2

Nominal and measured concentrations:

Nominal concentration: 100 mg/L loading rate WSF

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flask
- Material: glass; Size: 300 mL; Fill volume: 100 mL
- Initial cells density: 0.5E4 cells/mL
- Control end cells density: yes, 10.9E5 cells/mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6
- Other: The test vessels were shaken throughout the test period at 100 ± 5 oscillations/min.

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Culture medium different from test medium: no
- Intervals of water quality measurement: The temperature was continuously (once per hour) measured throughout the test period in a separate test vessel. The pH value was measured at the start and at the end of the test in one replicate.

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod: continuous light
- Light intensity and quality: 62.0 - 69.5 µE/m2*s

EFFECT PARAMETERS MEASURED: Algal growth was recorded daily by determining the number of cells per volume test solution.
- Determination of cell concentrations: fluorimeter

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): none

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50 (72h): 1.2 mg/L
- Other: The ErC50 value of the reference test is within the refined range of 1.19±0.27 mg/L, recommended based on an international ring test (ISO (2004). Water Quality - Freshwater algal growth inhibition test with unicellular green algae. European Standard EN ISO 8692, October 2004. ). Therefore, the results of this reference test are acceptable and the test conditions are reliable.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Yield (72h): NOECy >= 100 mg/l
Growth rate: ErC50 > 100 mg/l