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Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 Aug - 10 Sep 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Version / remarks:

2012

GLP compliance:

yes (incl. QA statement)

Remarks:

Sächsische Staatsministerium für Umwelt und Landwirtschaft, Germany

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all test concentrations
- Sample storage conditions before analysis: deep frozen (≤ - 18 °C)

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 200.2 mg test item filling with test medium up to 1000 mL (= stock solution A, corresponding to a concentration of 200.2 mg/L). The required volumes of the stock solution A were filled up to approximately 950 mL with test medium. Appropriate amount of algal suspension (dependent of the content of carbon C) were added and filled up to 1000 mL with test medium to reach of approximately 0.1 and 0.2 mg C/Daphnia/day. The test medium was prepared 1 day before the test start and aerated for 2 hours. The pH value of the stock solution was adjusted to lie within the specified range for the test using a sodium hydroxide solution.
- Controls: The control vessels contained test medium only.

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
- Age of parental stock (mean and range, SD): < 24 hours and not first brood progeny
- Feeding during test
- Food type: living algal cells of Desmodesmus subspicatus
- Amount: between 0.1 and 0.2 mg C/Daphnia/day
- Frequency: three times per week (medium renewals)

BREEDING CONDITIONS
Breeding was performed in glass beakers (50 mL) under the same conditions as in the test.
- Breeding conditions (same as test or not): same as test
- Type and amount of food: defined suspension of algae
<= 1 day old: 0.5 mL/50 mL M 4
3 to 10 days old: 1.0 mL/50 mL M 4
> 10 days old: 1.5 mL/50 mL M 4
- Feeding frequency: daily
- Health during acclimation (any mortality observed): not reported

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES:
Test animals were separated from the adults by means of a pipette.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

226 - 241 mg CaCO3/L

Test temperature:

19.5 – 21.3 °C

pH:

7.34 - 8.52

Dissolved oxygen:

6.33 - 9.72 mg/L

Nominal and measured concentrations:

Nominal: Control, 1.23, 3.70, 11.1, 33.3 and 100.0 mg/L
Recoveries: 180 - 111% (determined at the test start, once a week, and at the test end in the freshly prepared and spent test solutions)

Details on test conditions:

TEST SYSTEM
- Test vessel: beaker
- Material, size, headspace, fill volume: glass, fill volume: 50 mL
- Renewal rate of test solution (frequency/flow rate): three times per week
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10
- Biomass loading rate: 50 mL test solution per Daphnia

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: air saturated deionized water
- Conductivity: 1.0 µS/cm
- Culture medium different from test medium: no
- Intervals of water quality measurement: at test start and once a week

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours
- Light intensity: 18 μE/(m2 s1)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
number of offspring produced by each parent animal and number of dead parent animals; daily from the appearance of the first brood

Reference substance (positive control):

no

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

11.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks:

mean cumulative offspring per survivor

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

19.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks:

mean cumulative offspring per survivor

Remarks on result:

other: Confidence interval: 4.27 - 36.0 mg/L

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

- Mortality of parent animals: no significant mortality was observed
- No. of offspring produced per female (mean of 10 replicates):
Control: 87.2 ± 22.14
1.23 mg/L: 85.8 ± 21.84
3.70 mg/L: 85.8± 21.74
11.1 mg/L: 78.7 ± 19.84
33.3 mg/L: 75.0 ± 19.05
100.0 mg/L: 69.5 ± 17.38
- Type and number of morphological abnormalities: No visible signs of abnormalities of surviving Daphnia were observed.
- Type and number of behavioural abnormalities: No visible signs of abnormalities of surviving Daphnia were observed.
- Time to first brood release or time to hatch: The first offspring in the control replicates were observed between 9 and 11 days after test start. No significant difference to the control was observed at any of the test concentrations.

Reported statistics and error estimates:

Determination of NOECs and LOECs: Outlier-Test after Dixon & Hartley, Williams Multiple Sequential t-test
Determination of Effective Concentrations: Probit analysis using linear weighted regression

Validity criteria fulfilled:

yes

Reference 2

Endpoint:

long-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:

21 d

Dose descriptor:

NOEC

Effect conc.:

11.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks:

mean cumulative offspring per survivor

Remarks on result:

other: key, Source, Juckeland, 2013, Daphnia magna 21 d

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

19.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks:

mean cumulative offspring per survivor

Remarks on result:

other: Confidence interval: 4.27 - 36.0 mg/L

Remarks:

key, Source, Juckeland, 2013, Daphnia magna 21 d

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: key, Source, Juckeland, 2013, Daphnia magna 21 d

Description of key information

NOEC (21 d) = 11.1 mg/L based on reproduction (OECD 211; Daphnia magna, read-across)

Additional information

Experimental data on the chronic 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 according to OECD Guideline 211 and GLP. The test organism Daphnia magna was exposed to nominal test concentrations of 1.23, 3.70, 11.1, 33.3 and 100.0 mg/L for 21 days in a semi-static system. The test concentrations were analytically verified by HPLC analysis. The analytical dose verification determined recoveries of 80 - 111%. Thus, the results were based on nominal concentrations. The NOEC (21 d) based on reproduction was determined to be 11.1 mg/L. No mortality of parent animals was observed.

Based on the available read-across data the chronic effects 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 on aquatic invertebrates cannot be excluded.