2-chloro-N-[[[4-(trifluoromethoxy)phenyl]amino]carbonyl]benzamide

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: 88/302/EEC

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

not specified

Details on sampling:

The respiration rate of an activated sludge is measured after a contact time of 3 hours. The respiration rate of the same activated sludge in the presence of various concentrations of the test substance under otherwise identical conditions is also measured. The inhibitory effect of the test substance at a particular concentration is expressed as a percentage of the mean respiration rates of two controls.

Test organisms (species):

activated sludge

Details on inoculum:

The test organism was a mixed population of aquatic microorganisms (activated sludge).

Origin: aeration tank of a waste water treatment plant treating predominantly domestic sewage (Wupper area water authority) Pretreatment: aeration of the activated sludge; daily feed with synthetic medium pH of the suspension before application: 6.9.

Test type:

not specified

Total exposure duration:

3 h

Test temperature:

20 ± 2° C

Nominal and measured concentrations:

Test concentrations (mg/L) :
1000,
1800,
3200,
5600,
10000.

Details on test conditions:

**Test substance concentration in physico-chemical oxygen consumption control (mg/L): 10000
Type of application : direct weighing
Test concentration of the activated sludge : 360 mg/L suspended solids
Test temperature : 20 ± 2° C
Incubation time : 3 hours with permanent aeration

Reference substance (positive control):

yes

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

Triflumuron showed 44.3 % respiration inhibition of activated sludge at a test substance concentration of 10000 mg/L.

Results with reference substance (positive control):

Respiration inhibition 80.3% (40 mg/l test concentration).

Validity criteria fulfilled:

yes

Conclusions:

The study was performed using concentrations of 100, 1800, 3200, 5600 and 10000 mg/L. Triflumuron showed a 44.3% respiration inhibition (oxygen consumption)

Executive summary:

A study was performed to assess the toxicity of Triflumuron to bacteria. The study was conducted in accordance with the Commission Directive 88/302/EEC; Official Journal of the EC L133 Part C (1988). The activated sludge was exposed to Triflumuron at different concentrations. The respiration rate of each mixture was determined after aeration periods of 3 hours. Triflumuron showed 44.3 % respiration inhibition of activated sludge at a test substance concentration of 10000 mg/L. EC50 > 10000 mg/L

Description of key information

 The activated sludge was exposed to Triflumuron at different concentrations: 100, 1800, 3200, 5600 and 10000 mg/L. The respiration rate of each mixture was determined after aeration periods of 3 hours. Triflumuron showed 44.3 % respiration inhibition of activated sludge at a test substance concentration of 10000 mg/L.
EC50 > 10000 mg/L

Key value for chemical safety assessment

EC50 for microorganisms:

10 000 mg/L