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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
14 - 23 Sep 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report date:
2018

Materials and methods

Test guidelineopen allclose all
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)
GLP compliance:
yes (incl. QA statement)
Remarks:
The Department of Health of the Government of the United Kingdom

Test material

Constituent 1
Chemical structure
Reference substance name:
Pyridine-2-carboxylic acid
EC Number:
202-719-7
EC Name:
Pyridine-2-carboxylic acid
Cas Number:
98-98-6
Molecular formula:
C6H5NO2
IUPAC Name:
pyridine-2-carboxylic acid

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: control and 100 mg/L; Duplicate samples of each test concentration was taken for chemical analysis at 0 and 48 hours in order to determine the stability of the test item under test conditions.
- Sample storage conditions before analysis: All samples were stored frozen prior to analysis.

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A nominal amount of test item (100 mg) was dissolved in test water and the volume adjusted to 1 L to give the 100 mg/L test concentration. The prepared concentration was inverted several times to ensure adequate mixing and homogeneity.
- Eluate: no
- Differential loading: yes
- Controls: yes, test medium control
- Evidence of undissolved material: At the start and throughout the test all control and test solutions were observed to be clear colorless solutions.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: water flea
- Source: in-house laboratory cultures
- Feeding during test: none

HOLDING CONDITIONS
- Adult daphnids were maintained in 150 mL glass beakers containing 100 mL Elendt M7 medium in a temperature controlled room maintaining the water temperature at 18 to 22 °C and 16 h/8 h light cycle. Each culture was fed daily with a mixture of algal suspension (Desmodesmus subspicatus) and Tetramin® flake food suspension. Culture conditions ensured that reproduction was by parthenogenesis. Gravid adults were isolated the day before initiation of the test, such that the young daphnids produced overnight were less than 24 hours old. These young were removed from the cultures and used for testing.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h

Test conditions

Test temperature:
21 - 22 °C
pH:
control: 7.8 - 7.9
100 mg/L: 6.0 - 6.7
Dissolved oxygen:
control: 8.7 - 9.0 mg O2/L
100 mg/L: 8.7 - 8.9 mg O2/L
Nominal and measured concentrations:
nominal: control, 100 mg/L
measured: < LOQ, 98.5-99.0 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: beakers
- Type (delete if not applicable): covered to reduce evaporation
- Material, size, headspace, fill volume: glass, 150 mL, headspace: 50 mL, fill volume: 100 mL
- 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 was used to prepare the Elendt M7 Medium
- Culture medium different from test medium: same as test
- Intervals of water quality measurement: Water temperature was recorded daily throughout the test. Dissolved oxygen concentrations and pH were recorded at the start and termination of the test. The pH and dissolved oxygen concentration were measured using a Hach Flexi handheld meter whilst the temperature was measured using a Hanna Instruments HI 93510 digital thermometer. The light intensity during the light period was measured using an ATP Instrumentation Lux meter. The appearance of the test media was recorded daily.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light / 8 h darkness
- Light intensity: 910 - 974 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable)
- Immobilization and other adverse reactions were recorded after 24 and 48 h after start of exposure.

RANGE-FINDING STUDY
- Test concentrations: control, 0.1, 1.0, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: No immobilization was observed throughout the test. Thus, a limit test was considered justified.
Reference substance (positive control):
yes
Remarks:
potassium dichromate (tested periodically)

Results and discussion

Effect concentrations
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
- Mortality of control: 0%
- Abnormal responses: No sub-lethal effects of exposure were observed throughout the test.
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no, test solutions were clear and colorless
- Effect concentrations exceeding solubility of substance in test medium: no
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Relevant effect levels: EC50 (48 h): 1.2 mg/L (95% CI: 1.1 - 1.3 mg/L); NOEC (48 h): 0.56 mg/L
Reported statistics and error estimates:
An estimate of the EC50 values was given by inspection of the immobilization data.

Any other information on results incl. tables

0% immobilization was recorded during the study in the control as well as in the treatment.

Table 1: Analytical determinations

Time point [h]

Nominal concentration [mg/L]

Measured concentration [mg/L]

Percent of nominal [%]

0 h

Control

< LOQ

-

 

100

99.0

99

48 h

Control

< LOQ

-

 

100

98.5

99

Table 2: Validity criteria for OECD 202.

Criterion from the guideline

Outcome

Validity criterion fulfilled

In the control, including the control containing the solubilising agent, not more than 10% of the daphnids should have been immobilized.

0%

yes

The dissolved oxygen concentration at the end of the test should be ≥ 3 mg/L in control and test vessels.

8.7 - 9.0 mg O2/L

yes

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
For further details please refer to “Any other information on results incl. tables”.

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