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Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 - 29 Mar 2012

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

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

1992

GLP compliance:

yes (incl. QA statement)

Remarks:

Sächsische Staatsministerium für Umwelt und Landwirtschaft, Germany

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0 and 100 mg/L
- Sampling: at the start and at the end of the test
- Sample storage conditions before analysis: samples were frozen

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution was prepared by weighing of 53.0 mg test item and filling with dilution water up to 500 mL (= stock solution A, corresponding to 106.0 mg test item/L). The test solution of the chosen concentration was prepared directly in the test vessels by dilution of the stock solution A with dilution water immediately before the transfer of the Daphnia into the test vessels.
- Eluate: no
- Differential loading: no
- Controls: yes, test medium control without test substance

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: Landesanstalt für Umweltschutz Baden-Württemberg, Karlsruhe, Germany; holding and breeding in the test facility under standardised laboratory conditions test animals derived from a healthy stock, not first brood progeny
- Age at study initiation (mean and range, SD): < 24 hours
- Culturing conditions: in glass beakers (50 mL) under the same conditions as in the test; test animals were separated from the adults by means of a pipette
- Feeding during test: none

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

2 mmol/L CaCO3

Test temperature:

19.7 - 21.1 °C

pH:

7.63 - 7.84

Dissolved oxygen:

8.05 - 8.96 mg O2/L

Nominal and measured concentrations:

Nominal: 0 and 100 mg/L
Recoveries: 90.2 at 0 h and 102.3% at 72 h

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: glass beaker, test volume 10 mL
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: 2 mL test solution per Daphnia

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water according to ISO 6341, prepared 7 days in advance
- Conductivity of deionised water: ≤ 10 μS/cm
- Culture medium different from test medium: yes
- Intervals of water quality measurement: temperature recorded continuously, pH and dissolved oxygen at the start and at the end

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light : 8 h dark, daily
- Light intensity: approx. 1000 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
number of immobilised Daphnia per vessel (including discoloration, anomalies), 24 and 48 hours after start of exposure

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- No immobilisation was observed during the study
- Behavioural abnormalities: At any assessment no visible signs of abnormalities of surviving daphnids were observed.
- Mortality of control: none
- Other adverse effects control: none

Results with reference substance (positive control):

The reference item potassium dichromate was tested in a separate study at 0.88, 1.14, 1.48, 1.92 and 2.50 mg/L to control the sensitivity of the test system (the most recent study 06.12. – 08.12.2011)
EC50 (48 h) = 1.22 mg/L (95% CI 1.13 - 1.32 mg/L)
The reference item EC50 values are within the expected range of toxicity for reference toxicity tests performed at the test facility (range of 1.0 – 2.0 mg/L).

Reported statistics and error estimates:

Because a limit test was performed, a calculation and statistical evaluation was not applicable.

The measured concentrations of the susbtance in the test solutions remained at 90% of nominal values at the start of the test and at 102% at the end of the test (after 48 h). Therefore the toxicity results are based on the nominal concentrations.

Validity criteria fulfilled:

yes

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Please refer to the analogue justification attached to chapter 13.

Reason / purpose for cross-reference:

read-across source

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Source, RA-A, Juckeland, 2012, Daphnia magna 48 h

Description of key information

EC50 (48 h): > 100 mg/L (Daphnia magna; OECD 202, read-across)

Additional information

Experimental data on the acute toxicity of Reaction mass of dipotassium 2-(3,4-dimethyl-1H-pyrazol-1-yl) succinate and dipotassium 2-(4,5-dimethy-1H-pyrazol-1-yl) succinate to aquatic invertebrates are not available.The assessment was therefore based on data available for the conjugate acid Reaction mass of 2-(3,4-dimethyl-1H-pyrazol-1-yl)succinic acid and 2-(4,5-dimethyl-1H-pyrazol-1-yl)succinic acid (CAS 2241455-89-8).

The available study on the source substance was conducted as a limit test according to OECD Guideline 202 and GLP. The test organism Daphnia magna was exposed to the test substance at a nominal concentration of 100 mg/L for 48 hours. Analytical monitoring determined recovery rates of 90.2 at 0 h and 102.3% at 72 h. No immobilisation was observed during the study, and the EC50 (48 h) is thus determined to be > 100 mg/L (nominal).

Based on the available read-across data Reaction mass of dipotassium 2-(3,4-dimethyl-1H-pyrazol-1-yl) succinate and dipotassium 2-(4,5-dimethy-1H-pyrazol-1-yl) succinate is expected to be not acutely toxic to aquatic invertebrates.