Dodecyl nonan-1-oate

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

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 provided in Section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other:

Remarks:

Source: CAS 2306-88-9, BASF SE, 2013, activated sludge

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other:

Remarks:

Source: CAS 2306-88-9, BASF SE, 2013, activated sludge

Key result

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other:

Remarks:

Source: CAS 95912-86-0, BASF, 2013, activated sludge

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other:

Remarks:

Source: CAS 95912-86-0, BASF, 2013, activated sludge

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29 Aug 2012 - 05 Nov 2012

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Mainz, Germany

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test substance was added in the required amounts according to the test concentrations directly to the test vessels with about 234 mL deionized water. 16 mL synthetic medium were dosed to each test vessel with test substance and reference substance afterwards.
- Controls:
Blank control: To prepare the blank control assays 234 mL of deionized water and 16 mL synthetic medium were mixed.
Reference substance: 1000.0 mg of the reference substance was added to about 800 mL of deionized water and stirred at room temperature until the reference substance was completely dissolved. The pH value of the stock solution was measured and adjusted to 7.2 with 1 M sodium hydroxide solution. Following this the stock solution was made up to 1L with deionized water. The stock solution appeared colorless-clear and no undissolved reference substance was visible. Aliquots of the reference substance stock solution were dosed to the test vessels and made up with deionized water to a volume of 234 mL.

Test organisms (species):

activated sludge

Details on inoculum:

- Source: Municipal wastewater treatment plant of Mannheim, Germany. The sludge was collected on 29 Aug 2012 from the aeration tank of the plant.
- Preparation of inoculum for exposure: The activated sludge suspension was sieved with a fine woven mesh (mesh size about 1 mm). This suspension was pre-aerated over night at room temperature. At the next day the sludge suspension was washed once with drinking water and the suspension was adjusted to 3 g/L dry matter.
- Initial sludge concentration: 1.5 g/L dry substance

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20.7 - 21.3 °C

pH:

7.1 - 7.2

Dissolved oxygen:

> 7 mg O2/L

Nominal and measured concentrations:

Nominal: 1000, 500, 250, 125 and 62.5 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: Glass-beakers, 1L; 500 mL fill volume
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionized water

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Oxygen concentration (mg/L); at start and end of the experiment

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2

Reference substance (positive control):

yes

Remarks:

3,5 dichlorophenol

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/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: 6.0 mg/L

Reported statistics and error estimates:

The consumption rates were used for the determination of the ECx by the probit method based on Finney with the software TOXRAT Professional 2.10.

Reference 3

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline Study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Mainz, Germany

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Direct addition by initial weight into the test flasks. The test substance was weighed in the required amounts for the test concentrations directly to the test vessels with about 234 mL deionized water. 16 mL synthetic medium were dosed to each test vessel with test substance and reference substance afterwards. To prepare the blank control assays 234 mL of deionized water and 16 mL synthetic medium were mixed.
- Eluate: no
- Differential loading: yes
- Controls: yes, blank control with 234 mL of deionized water and 16 mL synthetic medium

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Source: Activated sludge from the municipal wastewater treatment plant of Mannheim, Germany was collected on 03 Sep 2012 from the aeration tank of the plant.
- Laboratory culture: no
- Preparation of inoculum for exposure: The activated sludge suspension was sieved with a fine woven mesh (mesh size about 1 mm). This suspension was pre-aerated over night at room temperature. At the next day the sludge suspension was washed once with drinking water and the suspension was adjusted to 3 g/L dry matter.
- Initial biomass concentration: 1.5 g/L dry matter

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20.8 - 21.1 °C

pH:

7.1 - 7.2

Dissolved oxygen:

During aeration: > 2 mg/L
Immediately before measurement: > 7 mg/L

Nominal and measured concentrations:

nominal: control, 62.5, 125, 250, 500, 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel
- Material, size, headspace, fill volume: Glass, 1 L, headspace: 500 mL, fill volume: 500 mL
- Aeration: yes
- No. of vessels per concentration (replicates): 2 replicates
- No. of vessels per control (replicates): 4 replicates

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionized water

OTHER TEST CONDITIONS
- Adjustment of pH: no

EFFECT PARAMETERS MEASURED:

TEST CONCENTRATIONS
- Spacing factor for test concentrations: ≤ 3.2

Reference substance (positive control):

yes

Remarks:

3,5 dichlorophenol

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/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 (3 h): 8.9 mg/L

Reported statistics and error estimates:

The consumption rates were used for the determination of the ECx by the probit method based on Finney with the software TOXRAT Professional 2.10.

Measured data of oxygen content in the test vessels at the begin and end of the evaluation time.

Concentration [mg/L]	Blank 1	Blank 2	Blank 3	Blank 4	62.5	62.5	125	125	250	250	500	500	1000	1000
O2 conc. Start [mg/L]	7.0	7.0	7.9	7.9	7.6	7.1	8.0	7.1	7.8	7.4	7.6	7.8	7.4	7.2
O2 conc. End [mg/L]	4.0	4.0	5.0	5.0	3.0	3.5	4.0	3.5	3.7	3.5	3.5	3.5	3.5	3.5
O2 consumption rate [mg/L	3.0	3.0	2.9	2.9	6.0	6.0	6.0	6.0	5.0	6.0	6.0	6.0	6.0	6.0
O2 consumption [min]	6.0	6.0	6.0	6.0	4.6	3.6	4.0	3.6	4.1	3.9	4.1	4.3	3.9	3.7
O2 consumption rate [ mg/Lxh]	30	30	29	29	46	36	40	36	49	39	41	43	39	37
Specific O2 consumption rate [mg/gxh]	20	20	19	19	31	24	27	24	33	26	27	29	26	25
Inhibition of respiration [%]	-	-	-	-	-56	-22	-36	-22	-66	-32	-39	-46	-32	-25

Description of key information

No effects up to the limit of water solubility (OECD 209); read-across

Additional information

There is no study available, in which the toxicity of the target substance lauryl nonanoate (CAS 17671-26-0) to microorganisms was assessed. Therefore, read-across to the two structurally related source substances Fatty acids, C8-10, C12-18-alkyl esters (CAS 95912-86-0) and octyl octanoate (CAS 2306-88-9) was conducted in accordance with Regulation (EC) No 1907/2006 Annex XI, 1.5. Both source substances are characterized by similar fatty acid chain lengths as well as alcohol components and are therefore considered suitable representatives for the assessment of the toxicity of the target substance to microorganisms. A detailed read-across justification is provided in the analogue justification in IUCLID Section 13.

Both available studies with suitable source substances were conducted according to OECD 209 and GLP with identical test design and findings. In both studies five, nominal concentrations of 62.5, 125, 250, 500, and 1000 mg/L test item were inoculated with 1.5 g/L activated sludge (dry matter) in a static test for 3 h and total oxygen concentration was followed. The test item was directly weighed into the test vessels. No analytical verification of the test item concentrations in the test solutions was performed. After 3 h exposure neither study observed any significant effect on the total respiration rate.

Based on the structural and chemical similarity of the target and source substances, the target substance is expected to exhibit a similar ecotoxicological profile. Therefore, it can be concluded that lauryl nonanoate (CAS 17671-26-0) will not exhibit toxic effects to microorganisms up to the limit of water solubility.