Fatty acids, C18-unsaturated, 1,6 Hexanediol Diester

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Please refer to the analogue justification attached to IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

72 h

Dose descriptor:

EL10

Effect conc.:

> 13 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

cell number

Remarks on result:

other: Key, source, CAS 16958-92-2, Exxon, 1997, S. subspicatus 72 h, RL2

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08 - 11 Aug 1997

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Analytical purity is not given. No NOEC value is derived. No growth curves are shown.

Qualifier:

according to guideline

Guideline:

ISO 8692 (Water Quality - Fresh Water Algal Growth Inhibition Test with Scenedesmus subspicatus and Selenastrum capricornutum)

Deviations:

no

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The substance was dispersed mechanically with help of a homogenizer (Ultra-turrax from Janke & Kunkel, Stauffen im Breisgau, Germany) at 10000 rpm for 2 minutes. It was then left to stand for 24 h at 20 °C and subsequently filtered (filter type: 589 Blue ribbon from Schleicher & Schüll, Dassel, Germany, pore size: 2.2 µm).

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- strain: SAG 86.81
- Source: laboratory bred obtained from Pflanzenphysiologisches Institut, Universität Göttingen, Germany
- Age of inoculum (at test initiation):
- Method of cultivation: The algae were hold in a stock culture under permanent light. The algae were transferred into fresh stock solution every week.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

22 ± 1 °C

pH:

not specified (it is stated that the pH of control did not deviate more than 1.5 during the test period)

Nominal and measured concentrations:

Nominal: 13, 130, 1300 and 13000 mg/L loading rate

Details on test conditions:

TEST SYSTEM
- Initial cells density: 10000 cells/mL
- Control end cells density: 1680000 cells/mL
- No. of vessels per concentration: 2
- No. of vessels per control: 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to guideline

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod: continuously light
- Light intensity and quality: 140 up to 160 µE/m2*s
- The test vessels were shaken at 100 rpm throughout the test.

EFFECT PARAMETERS MEASURED: Cell number was counted after 72 h test duration.
- Determination of cell concentrations: not specified

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EL0

Effect conc.:

>= 13 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(WAF)

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

EL10

Effect conc.:

> 13 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(WAF)

Basis for effect:

cell number

Details on results:

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

Description of key information

EL50 (72 h) > 13000 mg/L (nominal, WAF); NOEL (72 h) ≥ 13000 mg/L; Scenedesmus subspicatus (ISO 8692); read-across

Additional information

Experimental studies investigating toxic effects of the target substance Fatty acids, C18-unsaturated, 1,6 Hexanediol Diester on aquatic algae are not available. Thus, in accordance with Regulation (EC) No 1907/2006 Annex XI, 1.5 a read across to the structurally related source substance Bis(tridecyl) adipate (CAS 16958-92-2) was conducted to fulfill the data requirements according to Annex VII. In this case of read-across, the best suited (highest degree of structural similarity, nearest physico-chemical properties) read-across substance was used for the assessment. This read-across is justified in detail within the analogue justification in IUCLID Section 13.

The toxicity of Bis(tridecyl) adipate (CAS 16958-92-2) to freshwater algae was tested according to ISO guideline 8692 using Scenedesmus subspicatus as test organism. Filtered test item solutions of loading rates between 13 and 13000 mg/L were tested. A reduction of the cell numbers was not observed. The effect concentrations were based on the cell numbers. The determined EL50 (72 h) and EL10 (72 h) were > 13000 mg/L (nominal, WAF). The 72 h-NOEL was determined to be ≥ 13000 mg/L. Based on the available data for the read across substance and the very low water solubility (<0.57 µg/L at 20°C, pH 6.3) of the target substance toxic effects of Fatty acids, C18-unsaturated, 1,6 Hexanediol Diester on algae are not expected.