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

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31 Jul 1997

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

No analytics of the test substance concentration is performed. Some details about the test conditions are not specified (e.g., test vessels).

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

no inhibition of nitrification measured; no analytics of the test substance concentration performed

Qualifier:

according to guideline

Guideline:

other: EU guideline 87/302/EEC

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The composition and purity of the test substance was not known. It could not be discounted that there arise secondary constituents of the test substance with higher solubility than the main constituent. This may lead to an enrichment of the secondary constituents in watery extracts. Each test concentration therefore was prepared separately. Test substance and emulsifier were placed in dilution water (according to EU guideline 87/302/EEC) and were emulsified mechanically with help of a homogenizer (Ultra-Turrax from Janke & Kunkel, Stauffen im Breisgau, Germany) at 10000 rpm for 2 minutes. The emulsion were stable over 48 h.
- Chemical name of vehicle: Tween 80
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): The ratio of the test substance to emulsifier was 10:1.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Source: obtained from local sewage treatment plant, Essen-Rellinghausen, Germany; day of colection: 31 Jul 1997
- Preparation of inoculum for exposure: Sedimentation of the sludge and washing three times by charcoal-purified water.
- Initial biomass concentration: 3 g/L (dry matter content)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20 °C

pH:

7.5

Nominal and measured concentrations:

Nominal: 130, 1300 and 13000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: not specified
- Material, size, headspace, fill volume: not specified
- No. of vessels per concentration: 1
- No. of vessels per control: 2
- No. of vessels per vehicle control: 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to EU guideline 87/302/EEC

EFFECT PARAMETERS MEASURED: Oxygen consumption was recorded after 3 h test duration.

Reference substance (positive control):

yes

Remarks:

3,5 dichlorphenol

Duration:

3 h

Dose descriptor:

EC0

Effect conc.:

>= 13 g/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 13 g/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: EC50 = 26 mg/L (within the accepted range of 2-25 mg/L)

The emulsifier Tween 80 was formerly tested not to be toxic against activated sludge in a concentration range up to 2.0 g/L.

Reference 2

Endpoint:

activated sludge respiration inhibition testing

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:

3 h

Dose descriptor:

EC0

Effect conc.:

>= 13 g/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: source, RA-A, CAS 16958-92-2, Exxon, 1997, activated sludge 3h

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 13 g/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: source, RA-A, CAS 16958-92-2, Exxon, 1997, activated sludge 3h

Description of key information

EC10 (3 h) > 1.3 g/L (EU guideline 87/302/EEC, activated sludge microorganisms); read-across

Additional information

There is no study available, in which the toxicity of Fatty acids, C18-unsaturated, 1,6 Hexanediol Diester (EC 947-912-3) to aquatic microorganisms was assessed. Therefore, read-across to the structurally and chemically closely related source substance Ditridecyl adipate (CAS 16958-92-2) was performed in accordance with Regulation (EC) No 1907/2006 Annex XI, section 1.5 in order to fulfill the data requirements for this substance. 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 available study with the source substance Ditridecyl adipate (CAS 16958-92-2) was conducted according EU guideline 87/302/EEC. Activated sludge obtained from a STP, which predominantly treats domestic sewage, was used as inoculum. Test concentrations of 130, 1300 and 13000 mg/L were prepared using Tween 80 (substance: vehicle: 10:1) as vehicle. Based on the respiration rate no inhibition was observed in any treatment after a test period of 3 h. Hence, the EC10 (3 h) is determined to be > 13000 mg/L on the basis of the nominal concentration.

 

Based on the read across data it is assumed that Fatty acids, C18-unsaturated, 1,6 Hexanediol Diester (EC 947-912-3) has no inhibitory effects on the activity of activated sludge microorganisms.