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Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2018-01-10 to 2018-03-07
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
2004
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Version / remarks:
Council Regulation (EC) No. 440/2008 laying down test methods pursuant to Regulation (EC) No. 1907/2006 of the European Parliament and the council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH).
Deviations:
no
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
no
Remarks:
The test item has a low water solubility (<0.011 mg/L), thus, the compound cannot be detected with standard analytical methods.
Vehicle:
yes
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock preparation with a test item concentration of 100 mg/L was freshly prepared. For that purpose, the test item was weighed in a calibrated flask and vehicle was added. The preparation was stirred with a magnetic stirrer for 24 hours. Then the formulation was passed through a filter membrane (pore size: 0.2 µm). The filtrate was used for the study. The pH was not adjusted.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: water flea
- Strain/clone: Straus
- Age at study initiation: Offspring less than 24 hours old
- Stage and instar at study initiation: first insta
- Method of breeding: Parental daphnids are used for reproduction until they are about 6 weeks old. Thereafter, they are replaced by neonates. Daphnids are kept individually in 100 mL glass vessels containing approximately 60 mL reconstituted water (ELENDT M4 medium) at a water temperature of 20 ± 2 °C and a 16 hour light and 8 hour dark regime to ensure similar conditions as in the experiment. The parental daphnids are fed ad libitum with unicellular green algae Pseudokirchneriella subcapitata three times per week. Offspring are removed from the vessels at least twice per week.
- Source: the laboratories of Merck KGaA
- Feeding during test: no

ACCLIMATION
- Acclimation period: none
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h
Hardness:
232 mg CaCO3/L
Test temperature:
20.3 - 21.1 °C
pH:
7.73 - 7.76
Dissolved oxygen:
7.96 - 8.51 mg/L
Conductivity:
719 µS/cm
Nominal and measured concentrations:
Nominal 100 mg/L
No measured concentration.
Details on test conditions:
TEST SYSTEM
- Test vessel: Glass test tubes
- Type: open
- Material, size, headspace, fill volume: 20 mL glass test tubes containing 20 mL medium
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water (ELENDT M4 medium according OECD 202)
- Conductivity: 719 µS/cm
- Culture medium different from test medium: no
- Intervals of water quality measurement: at start and end of exposure

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16h light / 8h dark
- Light intensity: The mean light intensities were 551 Lux and 565 Lux prior to and at the end of the exposure period, respectively.

EFFECT PARAMETERS MEASURED: Immobilisation (daily)

VEHICLE CONTROL PERFORMED: no

RANGE-FINDING STUDY
- Test concentrations: 100 mg/L
- Results used to determine the conditions for the definitive study: no immobilisation observed at 100 mg/L
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Duration:
24 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: EC50 >0.011 mg/L (limit of water solubility)
Key result
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: EC50 >0.011 mg/L (limit of water solubility)
Details on results:
An aqueous solution of nominal 100 mg/L of the test item revealed no aquatic toxicity in the test system.

The 48h EC50 exceeded the water solubility of <0.011 mg/L (nominal >100 mg/L) and, thus, could not be determined in this study.

- Behavioural abnormalities: no
- Other biological observations: no
- Mortality of control: no
- Other adverse effects control: no
- Abnormal responses: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
Results with reference substance (positive control):
- Results with reference substance valid? yes
EC50 values with 95 % confidence intervals:
24h EC50 1.22 mg/L (1.07 – 1.47 mg/L)
48h EC50 0.86 mg/L (0.76 – 0.99 mg/L)

Table 1: Biological Results

Nominal concentration [mg/L]

Number of daphnids immobilized / exposed

% of daphnids immobilized

24 hours

48 hours

24 hours

48 hours

Control

0/20

0/20

0%

0%

100

0/20

0/20

0%

0%

 

Table 2: EC50-Values

Test Duration

EC50

24h

>0.011 mg/L (nominal >100 mg/L)

48h

>0.011 mg/L (nominal >100 mg/L)

 

Validity criteria fulfilled:
yes
Conclusions:
Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of the test item revealed no toxicity to daphnids.
The 48h EC50 was >0.011 mg/L (nominal >100 mg/L) and, thus, could not be determined in this study.



Executive summary:

The influence of the test item on Daphnia magna was assessed in a 48-h Acute Immobilisation Test according to OECD TG 202. For this purpose, juvenile daphnids, were exposed to a nominal test item concentration of 100 mg/L (limit test) in an open static system. 20 daphnids, divided into four replicates, each with five animals were used in the test item group and the control group. The daphnids were observed for immobilization after 24 and 48 hours of exposure.

The test item concentration in the reconstituted water was not quantified at the start and the end of this study. Because of the low water solubility (<0.011 mg/L), the compound cannot be detected with standard analytical methods and the development of an analytical method with a sufficiently low detection and quantification limit is complex.

Due to the absence of any adverse effects at the saturation concentration, the study was performed without analytical concentration verification.

No effect on the mobility of the daphnia was observed at a nominal concentration of 100 mg/L.

For the test item the following EC50 values were determined:

EC50 (24h) >0.011 mg/L (nominal >100 mg/L)

EC50 (48h) >0.011 mg/L (nominal >100 mg/L)

Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of the test item revealed no toxicity to daphnids. The 48h EC50 was >0.011 mg/L (nominal >100 mg/L) and, thus, could not be determined in this study. 

Description of key information

Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of the test item revealed no toxicity to daphnids. The 48h EC50 was >0.011 mg/L (nominal >100 mg/L) and, thus, could not be determined in this study (reference 6.1.3-1).

Key value for chemical safety assessment

Additional information

The influence of the test item on Daphnia magna was assessed in a 48-h Acute Immobilisation Test according to OECD TG 202. For this purpose, juvenile daphnids, were exposed to a nominal test item concentration of 100 mg/L (limit test) in an open static system. 20 daphnids, divided into four replicates, each with five animals were used in the test item group and the control group. The daphnids were observed for immobilization after 24 and 48 hours of exposure.

The test item concentration in the reconstituted water was not quantified at the start and the end of this study. Because of the low water solubility (<0.011 mg/L), the compound cannot be detected with standard analytical methods and the development of an analytical method with a sufficiently low detection and quantification limit is complex.

Due to the absence of any adverse effects at the saturation concentration, the study was performed without analytical concentration verification.

No effect on the mobility of the daphnia was observed at a nominal concentration of 100 mg/L.

For the test item the following EC50 values were determined:

EC50 (24h) >0.011 mg/L (nominal >100 mg/L)

EC50 (48h) >0.011 mg/L (nominal >100 mg/L)

Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of the test item revealed no toxicity to daphnids. The 48h EC50 was >0.011 mg/L (nominal >100 mg/L) and, thus, could not be determined in this study (reference 6.1.3-1).