diethyl 1-(2,4-dichlorophenyl)-5-methyl-4,5-dihydro-1H-pyrazole-3,5-dicarboxylate

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 Feb - 18 Mar 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: OECD 202, part 2

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: To obtain fresh stock solution for the test, the test substance was weighed out to a precision of 0.1 mg and dissolved in and made up to volume (3 ml) with acetone. Defined amounts of stock solution - or dilutions of it - were pipetted proportionally into the filled jars. The final amount of acetone did not exceed 0.1 mL/L test water. Stock solution and acetone were stirred vigorously with a glass rod. For all concentrations 3 liters of test solution were prepared freshly three times a week (renewal of test solution).

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Waterflea
- Strain: Daphnia magna STRAUS
- Source: The daphnids used in this test were bred in the animal maintenance room of the Oekobiologie of Hoechst Schering AgrEvo GmbH, Umweltforschung, (Environmental Sciences, Ecobiology).
- Age at study initiation: < 24 h
- Method of breeding: They were cultured in beakers (19x13 cm, approximate dimensions of internal height and diameter), containing initially 20
adult animals in 2 litre test water. Every ten days the daphnids were transferred into fresh water resulting in the initial biological loading. The Daphnia cultures were maintained at 20 ± 2°Celsius and a photoperiod of 16 hours light, 8 hours dark. All cultures were fed with unicellular green algae (Scenedesmus subspicatus CHODAT, strain 86.81 SAG) twice a week.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

231.1 - 248.9 mg CaCO3/L H2O

Test temperature:

19.6 - 19.9 °C

pH:

7.8 -7.9

Dissolved oxygen:

8.9 – 9.3 mg/L in fresh solutions and 7.3 – 8.8 mg/L in old solutions

Salinity:

-

Nominal and measured concentrations:

Nominal test concentrations of 0 (control), 0 (0.1 mL acetone /L), 0.32, 0.56, 1.0, 1.8 and 3.2 mg/L test item

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 600 mL glass beakers containing 400 mL test water at an approximate depth of 78 – 83 mm
- Renewal rate of test solution: test medium renewed on study days 3, 5, 7, 10, 12, 14, 17, 19 and 21
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): 4



TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The dilution water was well aerated artificial mineral medium (M4) water modified according to (Elendt 1990).
- Intervals of water quality measurement: The dissolved oxygen, pH, conductivity and temperature were measured throughout the study. In
addition, freshly prepared testing water was analysed for total hardness, total alkalinity and nitrite content.


OTHER TEST CONDITIONS
- Photoperiod: The light-dark cycle was 16L/8D
- Light intensity: illuminated by wide spectrum fluorescent lights

EFFECT PARAMETERS MEASURED: Effects on adult survival and reproductive capacity, i.e. numbers of dead and alive offspring were
investigated on study days 3, 5, 7, 10, 12, 14, 17, 19 and 21.


VEHICLE CONTROL PERFORMED: yes

Reference substance (positive control):

not specified

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks:

and offspring survival

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

1.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Biological results: There was no parental mortality in the control and any of the test item groups up to and

including 1800 μ/L. Significant mortality was observed at 3200 μg/L from Day 14 onwards. The 21d-EC50 was

therefore above the highest concentration of 3200 μg/L. First young were observed in the control and all testing

groups on Day 10. Throughout the study the number of alive young was significantly reduced at concentrations

> 560 μg/L test item. This effect was primarily due to reduced offspring number towards the end of the exposure

period.

Conclusion:

After 21-day exposure of daphnids to AE F107892 technical the NOEC for reproductive capacity and

offspring survival was considered to be 320 μg/L test item. The LOEC was 560 μg/L test item due to a doserelated

reduction in live young. The NOEC for parental mortality was 1800 μg/L due to increased (20%)

mortality at 3200 μg/L.

Description of key information

NOEC (21 d) = 0.32 mg/L with Daphnia magna (nominal, OECD 202 part II, reproduction)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.32 mg/L

Additional information

One key study on the parent substanc on the long-term toxicity of the substance to aquatic invertebrates is available. The key study was conducted according to OECD guideline 202, part II (1994). The test design was semi-static with five test concentrations ranging from 0.32 - 3.2 mg/L. The test solutions were prepared using acetone as vehicle. A NOEC (21 d) of 0.32 mg/L (nominal) was determined based on reproduction and offspring survival.

The supporting test on two different metabolites of the test item are available. The studies were conducted according to OECD guideline 211 under semi-static conditions with five test concentrations ranging from 0.32 - 3.2 mg/L. For one metabolite a NOEC (21 d) of 3.2 mg/L (nominal) based on reproduction was determined (2004). In the test on the chronic toxicity of the other metabolite a NOEC (21 d) of 32 mg/L (nominal) based on reproduction was recorded (2005).