3-methyl-1-phenyl-5-pyrazolone

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3-methyl-1-phenyl-5-pyrazolone

EC Number:

201-891-0

EC Name:

3-methyl-1-phenyl-5-pyrazolone

Cas Number:

89-25-8

Molecular formula:

C10H10N2O

IUPAC Name:

5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one

Sampling and analysis

Analytical monitoring:

yes

Remarks:

HPLC-UV

Test organisms

Test organisms (species):

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

Details on test organisms:

Strain No. 61.81 SAG.
The algae were supplied by the "Sammlung von Algenkulturen, Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Universität Göttingen", 37073 Göttingen, Germany.

Study design

Test type:

static

Water media type:

other: reconstituted water (OECD medium)

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

Microscopic examination of the shape of the algal cells after 72 hours.
Determination of cell density by spectrophotometrical measurement after 24h, 48h, 72h.

Test conditions

Hardness:

0,24 mmol/L (=24 mg/L) as CaCO3

Test temperature:

21.5 to 23.5°C (water temperature)

pH:

6.0 to 6.1

Dissolved oxygen:

Not specified

Nominal and measured concentrations:

Nominal: 100, 32, 10, 3.2, 1.0, 0.32 and 0.10 mg test item/L
Measured: 94.9, 27.4, 7.07, 2.37, 0.774, 0.267 and 0.088 mg test item/L

Details on test conditions:

Continuous illumination (mean light intensity: 5140 lux)

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 9.15 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 0.774 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

ca. 2.37 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 2.34 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 5

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 0.774 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 6

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

ca. 2.37 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

All reported results refer to geometric mean concentrations, since the test item concentrations were not within +/- 20% of the nominal concentrations during the test.
Based on the experimental results, the 72-h EyC50 (yield) was calculated to be 2.34 mg test item/L and the 72-h ErC50 (growth rate) was calculated to be 9.15 mg test item/L.
The 72-h NOEyC (yield) was determined to be 0.774 mg test item/L and the associated 72-h LOEyC (yield) was 2.37 mg test item/L.
The 72-h NOErC (growth rate) was determined to be 0.774 mg test item/L and the associated 72-h LOErC (growth rate) was 2.37 mg test item/L.