2-Butenoic acid, 4,4,4-trifluoro-3-(methylamino)-, ethyl ester, (2Z)-

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

ethyl (2Z)-4,4,4-trifluoro-3-(methylamino)but-2-enoate

EC Number:

801-277-8

Cas Number:

507448-65-9

Molecular formula:

C7H10F3NO2

IUPAC Name:

ethyl (2Z)-4,4,4-trifluoro-3-(methylamino)but-2-enoate

Test solutions

Details on test solutions:

Stock solution:
200.5 mg test item were mixed (polytron for 1 minute) and made up to 1000 ml with water.
The stock solution was freshly prepared at the start of the test.

Test concentrations:
Test item: 100.0, 32.0, 10.0, 3.2 and 1.0 mg/L
Reference item: 32.0, 10.0 and 3.2 mg/L

Calculated amounts of the test item to produce the desired test concentrations were mixed with 114 ml water and 6.4 ml nutrient solution (= test solution). Then 80 ml of the sludge were added.
The test item, 6.4 ml of the nutrient solution, 114 ml water and 80 ml of the sludge were mixed in 250 ml BOD flasks and aerated immediately.

Test organisms

Test organisms (species):

activated sludge

Details on inoculum:

- Source: Activated sludge collected from the sewage treatment plant of CH-4153 Reinach on November 3, 1999.
- pH at collection: The pH after collection was 7.7.
- Preparation: The preparation was carried out according to the method in the guideline.
- Separation method: The sludge was separated from the aqueous layer by settling instead of centrifugation.
- pH before use: The pH of the sludge before use was 7.8.
- Concentration: The sludge concentration in the test bottles was 1.71 g suspended solids/L.

Study design

Total exposure duration:

3 h

Test conditions

Test temperature:

20 ± 2 °C

pH:

The pH of sludge was 7.7 after collection and 7.8 after preparation (before use).
The pH of the mixtures in the test bottles was 8.2 – 8.3 at the end of exposure time.

Nominal and measured concentrations:

Test concentrations:
Test item: 100.0, 32.0, 10.0, 3.2 and 1.0 mg/L
Reference item: 32.0, 10.0 and 3.2 mg/L

Details on test conditions:

- Vessels: 250 ml BOD flasks with gas inlet
- Water: De-chlorinated drinking water
- Temperature: 20 ± 2 °C
- Duration: 3 hours.

Measurements:
Oxygen consumption per hour in mg/L with a ORION – Electrode Type 97-08, ORION Microprocessor Ionalizer 901 and plotted on a recorder.

Calculations:
The inhibitory values were calculated on the basis of the measured time dependant oxygen consumption of a blank and test solution.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: respitation inhibition

Effect concentrations 2

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: respiration inhibition

Effect concentrations 3

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: respiration inhibition

Details on results:

The inhibitory effect of the test item was expressed as a percentage of the mean respiration rates of two controls. Following values were calculated based on nominal concentrations:


The test item CA 2455 A was tested at nominal concentrations of 1.0, 3.2, 10.0, 32.0 and 100.0 mg test item/L after a contact time of 3 hours. The calculation of the following effect concentrations was based on these nominal values.

EC50 (3h) : > 100 mg/L

EC20 (3h) : > 100 mg/L
EC80 (3h) : > 100 mg/L

For the reference item (tested nominal concentrations) 3.2, 10 and 32 mg/L:

EC50 (3h) : 10.5 mg/L

EC20 (3h) : 3.8 mg/L
EC80 (3h) : 29.0 mg/L

Test Validity;
The deviation of the respiration rates in controls was 4 %. The EC 50 (3h) of the reference item was 10.5 mg/L. Since the deviation of the respiration rates of the controls was < 15 % and the EC 50 (3h) of the reference item was in the range of 5 to 30 mg/L, the test was valid in terms of the given validity criteria.

Conclusion:
The EC50 (3h) for CA 2455 A is > 100 mg/L. Based on the inherent toxicity of CA 2455 A in this test alone, the test item can be classified as: “not toxic to bacteria”.

Results with reference substance (positive control):

Refer to above results section.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The EC 50 (3h) for CA 2455 A is > 100 mg/L.
Based on the inherent toxicity of CA 2455 A in this test alone, the test item can be classified as:
“not toxic to bacteria”

Executive summary:

The respiration rate of an activated sludge fed with standard amount of synthetic sewage feed was measured after a contact time of 3 hours. The respiration rate of the same activated sludge was also measured in the presence of 1.0, 3.2, 10.0, 32.0 and 100 mg test item/L and 3.2, 10 and 32 mg/L reference item, respectively. 

The sludge concentration in the test bottles was 1.71 g suspended solids/L. 

 

The test with CA 2455 A the temperature was maintained constant at 20 ± 1°C. 

The pH of sludge was 7.7 after collection and 7.8 after preparation (before use). 

The pH of the mixtures in the test bottles was 8.2 – 8.3 at the end of exposure time. 

 

The EC50 (3h) of the reference item 3,5-Dichlorophenol was 10.5 mg/L

 

The inhibitory effect of the test item was expressed as a percentage of the mean respiration rates of two controls. Following values were calculated based on nominal concentrations:

 

EC50 (3h) : > 100 mg/L

 

EC20 (3h) : > 100 mg/L

EC80 (3h) : > 100 mg/L

 

Conclusion:

The EC 50 (3h) for CA 2455 A is > 100 mg/L. 

Based on the inherent toxicity of CA 2455 A in this test alone, the test item can be classified as:

“not toxic to bacteria”