Dodecanoic acid, 1,1'-[1,6-hexanediylbis[nitrilo(2,2-dimethyl-1-propanyl-3-ylidene)]] ester

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2004-10-06 to 2004-12-17

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1988

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

1984

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method:
For the pre-test, a stock solution containing 200 mg test item/L in deionized water was prepared. After 10 minutes in the ultrasonic bath the emulsion didn’t show any undissolved particles. The stock solution then was used to prepare solutions at the concentrations of 100, 10, and 1 mg/L. Because of the low water solubility, the treatment of 1000 mg/L was prepared by adding the appropriate volume of the test item directly.
In the main study, the test item was used directly.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, 67435 NW-Lachen-Speyerdorf.
- Pretreatment: The sludge was washed with tap water three times, then centrifuged and resuspended in tap water. 200 ml of the sludge were added to each test vessel.
- Initial biomass concentration: 4.1 g suspended solids/litre

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test temperature:

20 ± 2 °C

pH:

7.4 (control)

Nominal and measured concentrations:

Pre-test: Nominal concentrations: 1, 10, 100, 1000 mg/L of test item
Main test: 1000 mg/L of test item

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beakers as test vessels; narrow-neck glass with flat bottom as measuring flasks
- fill volume: 500 mL
- Aeration: purified air, using Pasteur pipettes, flow approx. 0.75 L/min.
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): two replicates before, two between and two after measuring O2-concentrations in the reference and test item replicates
- Sludge concentration: 1.64 g suspended solids/L in the main test

EFFECT PARAMETERS MEASURED:
- O2-consumption
- pH value at the beginning of the O2-measurement

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 0, 1, 10, 100 and 1000 mg/L
- Results used to determine the conditions for the definitive study: No inhibition was observed at 1000 mg/L.

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

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

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

Two valid experiments were performed.
In the pre-test, the test item was tested using four concentrations (ranging from 1000 to 1 mg/L). Duration of the test was three hours. Activated sludge was used as inoculum. It was taken from a domestic sewage treatment plant and washed before usage. The dry matter was determined as 4.0 g suspended solids/L, giving a concentration of 1.6 g sus-pended solids/L in the test. As the pre-test was performed for range-finding only, no reference item was tested.
No inhibition of the respiration of the activated sludge was detected in the treatments.
The main study was performed as a limit-test with a nominal concentration of 1000 mg/L. Conduct of the study was the same as in the pre-test. The dry matter of the activated sludge was determined as 4.1 g suspended solids/L, giving a concentration of 1.64 g suspended solids/L in the test. No inhibition was observed.

Results with reference substance (positive control):

3,5-Dichlorophenole was used as reference item. The EC50 of the reference item was determined as 8.2 mg/L (95% confidence interval: 6.4 – 10.2 mg/L), which lies within the recommended range of 5 – 30 mg/L.

Pre-Test

O₂-Consumption

No.	Content	Nominal Concentration in mg/L	O2Consumption in mg/(L*min.)	O2consumption in mg/(L*h)
1	Control	0	0.4119	24.71
2	Test Item	1000	0.4352	26.11
3	Test Item	100	0.4268	25.61
4	Test Item	10	0.3861	23.17
5	Test Item	1	0.3704	22.22
6	Control	0	0.4486	26.92

 Inhibition in %

Item	Nominal Concentration (mg/L)	Inhibition in %
Test Item	1000	-1.2
Test Item	100	0.8
Test Item	10	10.3
Test Item	1	13.9

Main Study

O₂-Consumption

No.	Content	Nominal Concentration (mg/L)	O2consumption in mg/(L*min.)	Mean O2cons. in mg/(L*min.)	Mean O2cons. in mg/(L*h)
1	Control	0	0.9702	0.9292	55.7534
2	Control	0	0.8883
3	Reference	2.5	0.7419	0.6991	41.9471
4	Reference	2.5	0.6563
5	Reference	5	0.5867	0.6125	36.7471
6	Reference	5	0.6383
7	Reference	10	0.4191	0.4363	26.1800
8	Reference	10	0.4536
9	Reference	20	0.3127	0.3257	19.5416
10	Reference	20	0.3386
11	Reference	40	0.1634	0.1599	9.5416
12	Reference	40	0.1556
13	Control	0	0.7520	0.7271	43.6274
14	Control	0	0.7022
15	Test Item	1000	0.9058	1.0110	60.6569
16	Test Item	1000	1.1161
17	Control	0	1.0116	0.9983	59.8994
18	Control	0	0.9850

The control vessels no. 13 and 14 were stated as outliers and were not used for the determination of the results, since the O₂-consumption was much lower than in the other control vessels.

Inhibition of the O₂consumption was calculated by comparison with the controls and is given in the following table:

Item	Nominal Concentration (mg/L)	Inhibition in %
Test Item	1000	-4.9
Reference	2.5	27.5
Reference	5	36.5
Reference	10	54.7
Reference	20	66.2
Reference	40	83.4

Validity criteria fulfilled:

yes

Conclusions:

Sika HardenerLH was tested for toxicity to aquatic micro-organisms in a 3 h-activated sludge respiration inhibition test according to EU method C.11.
The following results could be determined for the test item Sika Hardener LH (VP) (species: activated sludge from a domestic sewage treatment plant):
3h NOEC = 1000 mg/L
3h EC20 > 1000 mg/L
3h EC50 > 1000 mg/L

Executive summary:

Sika Hardener LH was assessed in an activated sludge respiration inhibition test, according to the EU-method C. 11 and OECD guideline 209. Two valid experiments were performed. In the pre-test, the test item was tested using four concentrations (ranging from 1000 to 1 mg/L). Duration of the test was three hours. Activated sludge was used as inoculum. It was taken from a domestic sewage treatment plant and washed before usage. The dry matter was determined as 4.0 g suspended solids/L, giving a concentration of 1.6 g suspended solids/L in the test. As the pre-test was perforned for range-finding only, no reference item was tested.

No inhibition of the respiration of the activated sludge was detected in the treatments.

The main study was performed as a limit test with a nominal concentration of 1000 mg/L. Conduct of the study was the same as in the pre-test. The dry matter of the activated sludge was determined as 4.1 g suspended solids/L, giving a concentration of 1.64 g suspended solids/L in the test.

3,5 -Dichlorophenole was used as reference item. The EC50 of the reference item was determined as 8.2 mg/L (95 % CL: 6.4 - 10.2 mg/L), which lies within the recommended range of 5 - 30 mg/L.

The following results could be determined for the test item Sika Hardener LH (VP)(species: activated sludge from a domestic sewage treatment plant):

3h NOEC = 1000 mg/L

3h EC20 > 1000 mg/L

3h EC50 > 1000 mg/L

Description of key information

Sika Hardener LH was assessed in an activated sludge respiration inhibition test, according to the EU-method C. 11 and OECD guideline 209. The 3-hour EC50 was determined to be greater than 1000 mg/L and the 3-hour NOEC determined at 1000 mg/L.

 

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

1 000 mg/L

Additional information

Sika Hardener LH was assessed in an activated sludge respiration inhibition test, according to the EU-method C. 11 and OECD guideline 209. Two valid experiments were performed. In the pre-test, the test item was tested using four concentrations (ranging from 1000 to 1 mg/L). Duration of the test was three hours. Activated sludge was used as inoculum. It was taken from a domestic sewage treatment plant and washed before usage. The dry matter was determined as 4.0 g suspended solids/L, giving a concentration of 1.6 g suspended solids/L in the test. As the pre-test was perforned for range-finding only, no reference item was tested.

No inhibition of the respiration of the activated sludge was detected in the treatments.

The main study was performed as a limit test with a nominal concentration of 1000 mg/L. Conduct of the study was the same as in the pre-test. The dry matter of the activated sludge was determined as 4.1 g suspended solids/L, giving a concentration of 1.64 g suspended solids/L in the test.

3,5 -Dichlorophenole was used as reference item. The EC50 of the reference item was determined as 8.2 mg/L (95 % CL: 6.4 - 10.2 mg/L), which lies within the recommended range of 5 - 30 mg/L.

The following results could be determined for the test item Sika Härter LH (VP)(species: activated sludge from a domestic sewage treatment plant):

3h NOEC = 1000 mg/L

3h EC20 > 1000 mg/L

3h EC50 > 1000 mg/L