Benzenamine, 3-(4-methyl-1H-imidazol-1-yl)-5-(trifluoromethyl)-

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07 March - 25 March 2005

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

641571-1 1-1

IUPAC Name:

641571-1 1-1

Details on test material:

- Name of test material (as cited in study report):AMN 107 B6
- - Physical state:solid
- Analytical purity:100.3 %
-- Lot/batch No.:CHAD0409
- Expiration date of the lot/batch:30 June 2005
- - Stability under test conditions:Stable
- Storage condition of test material:At room temperature in the dark

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Scenedesmus capricornutum

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

7.2 mg/L

Nominal / measured:

nominal

Conc. based on:

dissolved

Basis for effect:

cell number

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

24 mg/L

Nominal / measured:

nominal

Conc. based on:

dissolved

Basis for effect:

growth rate

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the present study with Selenastrum capricornutum, AMN107 B6
reduced growth rate of this fresh water algae species significantly at 4.6 mgll and higher.
The ECSOfo r cell growth inhibition (EBCS00:- 72h) was 7.2 mg/l with a 95% confidence interval
ranging from 4.1 to 13 mg/l.
As growth rate is derived from the slope under the growth curve in a logarithmic plot, the
measure of the specific growth rate is preferable aver biomass following from the mathematical
nature of exponential growth.
The EC50 for growth rate reduction (ERCSO0:- 72h) was 24 mgll with a 95% confidence interval
ranging from '1 3 to 45 mgll.
The NOEC for cell growth inhibition was 1.0 mgll, the NOEC for growth rate reduction was 2.2 mg/l.

Executive summary:

Selenastrum capricornutum, Fresh Water Algal Growth Inhibition Test with AMN 107 B6. The study procedures described in this report were based on the IS0 International Standard 8692, 1989. In addition, the procedures were designed to meet the test methods and validity criteria of the EEC directive 92/69, Part C.3, 1992, the OECD guideline No. 201, 1984 and the OECD series on testing and assessment number 23,2000. The batch of AMN 107 B6 was a faintly beige powder with a purity of 100.3%. Analytical results confirmed that AMNI 07 B6 was completely soluble in test medium at the concentrations tested. The project started with a range-finding test exposing exponentially growing algal cultures to a blank-control and a range of AMN 107 B6 concentrations between 0.1 and 100 mg/l increasing by a factor of 10. The results showed that the expected EC, for cell growth inhibition was between 1.0 and 10 mg/l. The expected EC, for growth rate reduction was between 10 and ,100 mg/l. The analytical results showed that the measured concentration in samples taken from an AMN107 B6 concentration of 1.0 mg/l was in agreement with nominal and stable under test conditions for at least 72 hours. The project was continued with a final test exposing exponentially growing algal cultures to a blank-control, a 0.45 pm filtered solution prepared at nominally 46 mg/l and dilutions of the filtrate representing nominal concentrations of 1 .O, 2.2, 4.6, 10 and 22 mg/l. The initial algal cell density was 1 o4 cells/ml and the total test period was 72 hours. Samples for analytical confirmation of actual exposure concentrations were taken from all test concentrations at the start and the end of the test period. Analyses of the samples taken during the final test showed that measured concentrations were in agreement with nominal throughout the 72-hour test period (84-98%). Hence, all results were based on nominal concentrations. Thus, it can be concluded that the observed undissolved material before filtration did not originate from the test substance itself. The study met the acceptability criteria prescribed by the protocol and was considered valid. AMN 107 B6 reduced growth rate of this fresh water algae species significantly at 4.6 mgll and higher. The EC, for cell growth inhibition (EBC5,: Q-72h) was 7.2 mg/l with a 95% confidence interval ranging from 4.1 to '1 3 mg/l. As growth rate is derived from the slope under the growth curve in a logarithmic plot, the measure of the specific growth rate is preferable over biomass following from the mathematical nature of exponential growth. The EC5, for growth rate reduction (ERC5,: 0-72h) was 24 mg/l with a 95% confidence interval ranging from 13 to 45 mg/l. The NOEC for cell growth inhibition was 1.0 mg/l, the NOEC for growth rate reduction was 2.2 mg/l.