3-bromo-1-(3-chloropyrid-2-yl)-5-methyl-1H-pyrazole

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 March 2020 to 06 April 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

BT internal code: 297/19/C.
Storage Condition: Dark, room temperature (15-25°C), < 70 % relative humidity.

Analytical monitoring:

yes

Details on sampling:

Concentrations:
4.27 - 9.39 - 20.66 - 45.45 - 100.00 mg/L of test item in ISO medium containing 0.01 % acetone as solvent plus two untreated control groups (with and without solvent).
Sampling method:
20 daphnids, divided in 4 replicates of 5 daphnids, were used for each group.
The test organisms were exposed to the test solutions for 48 hours, with renewal of the test solutions after 24 hours. The number of mobile and immobile daphnids was counted at 24 and 48 hours after the beginning of the test.
The samples to be analysed were collected as follows: at the start of the test from fresh test solutions (T0), at the renewal from the freshly prepared and the spent test solutions (T24), as well as at the end of the test from the spent test solutions (T48); the spent samples were taken after the pooling of the replicates. The samples were stored deep-frozen at ≤ -18°C prior to analysis. Analysis was performed within one week after termination of the biological part of the experiment.
The samples to be analysed were collected as follows:
- 7 samples at 0 hours, from the fresh solutions: 2 untreated controls, 5 concentrations of test item.
- 7 samples at 24 hours, from the aged solutions: 2 untreated controls, 5 concentrations of test item.
- 7 samples at 24 hours, from the fresh solutions: 2 untreated controls, 5 concentrations of test item.
- 7 samples at 48 hours, from the aged solutions: 2 untreated controls, 5 concentrations of test item.
The samples were diluted to the calibration range with Diluent before the analysis. Each sample was measured by double injection and the content of test item in the test samples was calculated based on the calibration curve equation obtained in the same chromatographic session.

Vehicle:

no

Details on test solutions:

All stock and test solutions were prepared in ISO medium containing 100 μL/L solvent (Acetone, 0.01%).
At the start of the test, a stock solution of 100 mg test item/L was prepared as follows: 100.0 mg test item were added to a 1 L volumetric flask containing test medium.
C1: 4.27 Nominal test item concentration [mg/L] ;
C2: 9.39 Nominal test item concentration [mg/L];
C3: 20.66 Nominal test item concentration [mg/L];
C4: 45.45 Nominal test item concentration [mg/L];
C5: 100.00 Nominal test item concentration [mg/L].

Test organisms (species):

Daphnia magna

Details on test organisms:

Species: Daphnia magna.
- Age: < 24 hours old.
- Source: In house breeding at the Test Facility.
- Diet: No feeding during the test.
- Housing (before the test): Under breeding conditions, the test organisms were fed with algae suspension (Pseudokirchneriella subcapitata) and were maintained in reconstituted water.
- pH of medium: 6 - 9.
- Dissolved oxygen: ≥ 3 mg/L.
- Maintained in thermostatic chamber at the temperature range of 20±2°C, with a photoperiod of 16 hours light and 8 hours dark.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

Between 140 and 250 mg/L (as CaCO3).

Test temperature:

20.0 - 20.5°C (temperature of the test medium).
19.4 - 20.3°C (temperature of the thermostatic chamber).

pH:

In the range of 6 - 9.

Dissolved oxygen:

≥ 3 mg/L.

Nominal and measured concentrations:

Nominal test item concentration [mg/L]: 4.27 - 9.39 - 20.66 - 45.45 - 100.00 mg/L.

Details on test conditions:

The test was conducted in a thermostatic chamber designed to maintain the test conditions specified in the protocol and in agreement with OECD 202 (2004).
The temperature and light intensity values in the chamber were measured continuously during the test using a data-logger system.
During the exposure period, the temperature measured in the medium was in the range of 20.0 - 20.5 °C, the temperature measured in the thermostatic chamber was in the range of 19.4 - 20.3 °C, the light intensity was at maximum 862 Lux and a photoperiod of 16 hours light and 8 hours dark was applied.
Dissolved oxygen concentration and pH values were measured in the treated and untreated solutions, at the beginning and at the end of the test and at the test solutions renewal..
The pH of the test medium (aerated for at least 2 hours with an air pump) was in the range of 6-9 and the dissolved oxygen concentration was ≥ 3 mg/L. The pH in the test solutions did not increase by more than 1.5 units during the test. The hardness of the medium at the start of the test was 220 mg/L CaCO3 (in the range of 140 and 250 mg/L as CaCO3).

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

ca. 29.34 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

ca. 59.82 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

45.45 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

20.66 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Mortality of control: 0 death.
- Other adverse effects control: 0 adverse effects.
- Immobilisation of control: 0 immobilisation.

Reported statistics and error estimates:

There were no significant statistical differences between control and solvent control, therefore the treated groups were compared with the solvent control.

Percent immobilisation after 24 and 48 hours of exposure of Daphnia magna to the Test item:

Code	Nominal test item conc. [mg/L]	Number of exposed daphnids	Response at 24 h		Response at 48 h
			Number of immobilised	%I	Number of immobilised	%I
CTRL	0.00	20	0	0	0	0
CT SOLV	0.00	20	0	0	0	0
C1	4.27	20	0	0	0	0
C2	9.39	20	0	0	0	0
C3	20.66	20	0	0	1	5
C4	45.45	20	0	0	5	25
C5	100.00	20	1	5	17	85

Effect on Daphnia magna after 48 h-exposure to the Test item, in relation to the control:

Code	Test item concentration [mg/L]	%I
C1	4.27	0
C2	9.39	0
C3	20.66	5
C4	45.45	25 +
C5	100.00	85 +

+ indicates a significant difference compared to the untreated control (Step-down Cochran-Armitage Test Procedure (α = 0.050; one-sided greater)

Effect concentrations of the Test item on Daphnia magna after 48 h exposure:

Endpoint (48 hours)	Test item concentration [mg/L]	Confidence limits
		Lower	Upper
EC10	29.34	17.30	38.39
EC20	37.47	25.34	47.24
EC50	59.82	47.48	77.78
LOEC	45.45	-	-
NOEC	20.66	-	-

Validity criteria fulfilled:

yes

Remarks:

According to OECD 202 (2004), all validity criteria validity criteria are met.

Conclusions:

The acute immobilisation test was performed, under semi-static conditions, to assess the effects of test item 3-bromo-1-(3-chloro-2-pyridyl)-5-methyl-1H-pyrazole on Daphnia magna after 48 hours of exposure.
20 daphnids, less than 24 hours old, were exposed to 4.27 - 9.39 - 20.66 - 45.45 - 100.00 mg/L of test item in ISO medium containing 0.01 % of the solvent acetone, plus two untreated control groups (with and without solvent).
After 48 hours, the endpoints based on the test item nominal concentrations were estimated to be the following:
- EC10 29.34 mg/L; EC20 37.47 mg/L; EC50 59.82 mg/L;
- Corresponding LOEC 45.45 mg/L;
- Corresponding NOEC 20.66 mg/L.
No other effects were observed on the exposed organisms.
The validity criteria of OECD 202 (2004) were fulfilled.
Based on EU regulation 1272/2008 the results lead to classification as hazardous to aquatic environment, chronic category 3 (H412: Harmful to aquatic life with long lasting effects.).

Executive summary:

The acute immobilisation test was performed under semi-static conditions to assess the effects of test item 3-bromo-1-(3-chloro-2-pyridyl)-5-methyl-1H-pyrazole on Daphnia magna after 48 hours of exposure.

20 daphnids, less than 24 hours old, were exposed to 4.27 - 9.39 - 20.66 - 45.45 - 100.00 mg/L of test item in ISO medium, plus two untreated control groups (with and without solvent).

The analytical determination of the active ingredient content showed a mean recovery of 95.00% in the fresh samples and 93.71% in the aged samples. Accordingly, the assessment of the effects was based on the nominal concentrations of the test item.

After 48 hours, the endpoints based on the test item nominal concentrations were estimated to be the following:

- EC10 29.34 mg/L; EC20 37.47 mg/L; EC50 59.82 mg/L;

- Corresponding LOEC 45.45 mg/L;

- Corresponding NOEC 20.66 mg/L.

No other effects were observed on the exposed organisms.

The validity criteria of OECD 202 (2004) were fulfilled.

Description of key information

Short-term toxicity to aquatic invertebrates, Daphnia magna, according OECD 202:

The acute immobilisation test was performed under semi-static conditions to assess the effects of test item 3-bromo-1-(3-chloro-2-pyridyl)-5-methyl-1H-pyrazole on Daphnia magna after 48 hours of exposure.

After 48 hours, the endpoints based on the test item nominal concentrations were estimated to be the following:

- EC10: 29.34 mg/L; EC20: 37.47 mg/L; EC50: 59.82 mg/L;

- Corresponding LOEC: 45.45 mg/L;

- Corresponding NOEC: 20.66 mg/L.

No other effects were observed on the exposed organisms.

The validity criteria of OECD 202 (2004) were fulfilled.

Based on EU regulation 1272/2008 the results lead to classification as hazardous to aquatic environment, chronic category 3 (H412: Harmful to aquatic life with long lasting effects.).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

59.82 mg/L