Pyrazolo[5,1-b]quinazolin-9(1H)-one, 2-methyl-

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2000-05-26 - 2000-06-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline compliant study.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

April 1984

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

December 1992

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Version / remarks:

April 1996

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-methyl-1H,9H-pyrazolo[3,2-b]quinazolin-9-one

EC Number:

616-079-5

Cas Number:

74336-55-3

Molecular formula:

C11 H9 N3 O

IUPAC Name:

2-methyl-1H,9H-pyrazolo[3,2-b]quinazolin-9-one

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0, 3.13, 12.5, 100 mg/L
- Sampling method: At the start of the test (after 0 h) and at the end of the test (after 48 h) samples from vessels without daphnids were analysed.
- Sample storage conditions before analysis: Samples were stored in the fridge.

Test solutions

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock solution was prepared by stirring the test substance in the vehicle for about 20 hours at 20 °C.
- Chemical name of vehicle: M4 medium
- Concentration of vehicle in test medium (stock solution and final test solution): 100 mg/L
- Evidence of undissolved material (e.g. precipitate, surface film, etc): Precipitation was observed. Undissolved test substance was removed by centrifugation before delution of the stock solution.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain: STRAUS 1820
- Source: in house bred
- Age at study initiation (mean and range, SD): 2 - 24 hours
- Feeding during test: No

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

No

Test conditions

Hardness:

2.37 mmol/L

Test temperature:

20.3 - 20.5 °C

pH:

8.1

Dissolved oxygen:

7.6 - 8.5

Salinity:

Not applicable

Nominal and measured concentrations:

nominal: 0, 3.13, 6.25, 12.5, 25, 50, 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: test tubes consisting of glass with a flat bottom (Nominal volume 20 mL)
- Aeration: none
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: 0.5 animals/mL

TEST MEDIUM / WATER PARAMETERS
- Alkalinity: 0.83 mmol/L
- Conductivity: 617 µS/cm
- Culture medium different from test medium: no
- Intervals of water quality measurement: The pH and oxygen content of the test solutions was measured at the start of the test in an additional fifth replicate per concentration and at the end of the exposure in replicate one of all test concentrations and the control. Temperature was measured continuously during the whole period in a separate vessel filled with water proximal to the test vessels.

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: day : night rhythm = 16 : 8 h
- Light intensity: About 2 - 7 µE/(m^2 * s) at a wave length of 400 - 700 nm

EFFECT PARAMETERS MEASURED: Swimming ability of the test animals visually inspected after 0, 24 and 48 hours

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

4.01 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 12.5 mg/L (nominal)

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

5.68 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 17.7 mg/L (nominal)

Effect concentrations 3

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

8.03 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 25 mg/L (nominal)

Details on results:

- Mortality of control: No mortality observed.
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No
- Effect concentrations exceeding solubility of substance in test medium: No

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Mortality: Yes
- EC50/LC50: 0.75 mg/L

Reported statistics and error estimates:

For the statistical calculation of the EC50 the moving average method was used (48h)

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

EC50 (48 h) = 5.68 mg/L

Executive summary:

The 48–hr-acute toxicity of the test substance to Daphnia magna was studied under static conditions according to OECD guideline 202 and EU method C.2 (BASF, 2000). Daphnids were exposed to control and test chemical at nominal concentrations of 0. 3.13, 6.25, 12.5, 25, 50 and 100 mg/L for 48 hours. Signs of immobilization were observed daily. The analytical recovery rate was below 80% in all analysed test solutions after 48 hours. The effective concentrations are therefore based on a median analytical recovery rate of 32.1 % between 0 and 48 hours. The 48 – hour EC50 was 5.68 mg/L (nominal 17.7 mg/L). This study is classified as acceptable (all validity criteria were fulfilled) and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.