3-tert-butyl-1-(3,5-dicarboxyphenyl)-1H-pyrazol-5-aminium chloride

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:

13 August 2019 to 16 August 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Version / remarks:

28th July 2011

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3-tert-butyl-1-(3,5-dicarboxyphenyl)-1H-pyrazol-5-aminium chloride

EC Number:

941-661-3

Molecular formula:

C15H18ClN3O4

IUPAC Name:

3-tert-butyl-1-(3,5-dicarboxyphenyl)-1H-pyrazol-5-aminium chloride

impurity 1

Reference substance name:

Unidentified impurity

IUPAC Name:

Unidentified impurity

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Test solutions were analysed at the beginning and end of the test

Test solutions

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Concentration of vehicle in test medium : Test solutions with nominal concentrations 6.25, 12.5, 25.0, 50.0 and 100.0 mg/l

Test organisms

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

Pseudokirchneriella subcapitata (formerly known asSelenastrum capricornutum)

Strain number: 61.81 SAG (identical strains: CCAP 278/4; UTEX 1648; ATCC 22662)

Source: The algae were supplied by the SAG: Collection of Algal Cultures, Inst. Plant Physiology, and University of Göttingen, GERMANY. Cultured under standardised conditions (see OECD 201) in the Ecotoxicological Laboratory of Citoxlab Hungary Ltd.

Justification of species: The species of Pseudokirchneriella subcapitata used, being a fast-growing species, is convenient for culturing and testing and is a recommended species by relevant guidelines.

Culture conditions: Stock cultures are small algal colonies that are inoculated onto agar regularly. These are transferred to fresh agar medium at least once every two months and are maintained under standardised conditions according to the test guidelines. The pre-culture is intended to give a quantity of algae suitable for the inoculation of test cultures. The pre-culture was prepared with the OECD algal growth medium, incubated under the same conditions as the test and used when still growing exponentially, normally after an incubation period of about three days. When the algal cultures contain deformed or abnormal cells, they were discarded.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

21.9 - 23.4ºC

pH:

4.39 - 8.99

Nominal and measured concentrations:

Analytical measured concentrations deviated not more than 20% from the nominal, therefore the results are based on nominal test item concentrations.

Details on test conditions:

TEST SYSTEM
- No. of organisms per vessel: ~1000 algal cells/ml
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6




OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Light intensity and quality: 75.2 lux


EFFECT PARAMETERS MEASURED
- Determination of cell concentrations:counting chamber

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

62.31 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

50.01 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

49.86 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 5

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

50 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

There were no morphological deviations of the algal cells during the experiment.

Reported statistics and error estimates:

The cell density in the control cultures increased by the factor of 67.67 within three days.
The mean coefficient of variation for section-by-section specific growth rates (days 0-1; 1-2; 2-3) in the control cultures was 6.56 %.
The coefficient of variation of average specific growth rates during the whole test period (day 0-3) in the control cultures was 1.21 %.
All validity criteria were met; therefore, the study can be considered as valid.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 72h EC50 (growth rate) was determined to be 62.31 mg/l.