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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:
2011-02-15 to 2011-02-23
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted in compliance with minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2011
Report date:
2011

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
5-Bromo-1H-pyrrolo[2,3-b]pyridine
EC Number:
629-247-8
Cas Number:
183208-35-7
Molecular formula:
C7H5BrN2
IUPAC Name:
5-Bromo-1H-pyrrolo[2,3-b]pyridine
Test material form:
other: solid
Details on test material:
Solid
Purity: >99%

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
HPLC analyses of the test substance concentrations were conducted in the definitive test at the beginning of the test and after 24 h and 48 h of incubation, respectively.

Test solutions

Vehicle:
no
Details on test solutions:
Prior to the definitive test a non-GLP range finding test with nominal concentrations of 1, 10 and 100 mg/L was performed.
Based on the results of this range finding test the following nominal test concentrations for the definitive test were selected 0.625, 1.25, 2.5, 5 and 10 mg/1. Due to the limited water solubility of the test substance, only the water accommodated fractions were tested.
These water accommodated fractions were prepared by addition of the respective amounts of an acetonic stock solution to empty glass vessels. After complete evaporation of the solvent, the aerated Daphnia medium was added. The test solutions were moderately stirred overnight followed by filtration (MILLIPORE AP15 glass fibre filter). The resulting water accommodated fractions were used in the test.
100 mL of the filtered test solutions were filled in one of the two replicate test vessels. The solution was aerated by stirring for about 0.5 h. 0 2 concentration and pH was measured. The pH was adjusted if necessary. Afterwards, half of the solution (50 mL) was filled in the 2nd replicate test vessel.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
Daphnia maqna (Straus, 1820).
Young daphnia with an age of < 24 hours were selected for the test.
Renewal of the cultures: After 7 days of cultivation half of the medium twice a week.
Temperature o f medium: 20 °C constant within +/-2°C
Feeding: Daily except at weekends.
Illumination: 16 h per day
Medium: Continuously aerated Elendt M4 medium prepared with deionised water (conductivity <1.5 uS/cm).

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h

Test conditions

Test temperature:
20°C +/- 2°C
pH:
6.8-7.8
Dissolved oxygen:
4.9-6.6
Details on test conditions:
Test type: Static
Test duration: 48 hours
Test vessels: 100 ml, all-glass
Medium: I Continuously aerated Elendt M4 medium; prepared with deionised water (conductivity <1.5 uS/cm
Number of daphnia: 40 per concentration
Loading: 20 per vessel containing 50 ml medium
Light: 16 hours photoperiod daily
Daphnia, aged less than 24 h, were acclimatised to the test medium for about 1 h before introduction into the formulated test media
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
7.25 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% 6.68-7.85 mg/L
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
6.42 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% 5.62-7.41 mg/L
Duration:
24 h
Dose descriptor:
NOEC
Effect conc.:
4.68 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
4.71 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
Using the water accommodated fractions significant effects (>10% immobilization) were observed at 8.83 mg/1 (72.5%)and 8.91 mg/1 (97.5%) with respect to the analytically determined concentration after 24 and 48 h of exposure, respectively.
No significant effects were observed at all other concentrations and in the control after 24 and 48 h of exposure
Almost 100% immobilization was detected at 8.91 mg/1 with respect to the analytically determined concentration after 48 h.
Results with reference substance (positive control):
Periodically acute reference tests were conducted with potassium dichromate
Reported statistics and error estimates:
The median effective concentration (EC50 value) is the concentration estimated to immobilize 50% of the Daphnia after 24 or 48 h of exposure. Those individuals not able to swim within 15 s after gentle agitation of the test vessel are considered to be immobile.
The EC values at 24 and 48 h of exposure will be calculated from the percentage response (number of immobile Daphnia) and the logarithms of the corresponding nominal test substance concentrations.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Based on the analytically determined concentrations the 24 and the 48 h EC50 values of the test item are 7.25 mg/L (95% confidence
interval: 6.68- 7.85 mg/L) and the 6.42 mg/L (95% confidence interval: 5.62- 7.41 mg/L), respectively
Executive summary:

INTRODUCTION: The acute toxicity of the test item to Daphnia magna was investigated under static exposure conditions over a period of 48 h. The applied nominal test concentrations were 0.625, 1.25, 2.5, 5 and 10 mg/L. 40 individual Daphnia divided in 2 test vessels were exposed to each concentration of the test substance.

METHOD: HPLC analyses of the test substance concentrations were conducted at the beginning of the test and after 24 h and 48 h of exposure, respectively. The analyses revealed that the test material was almost completely dissolved and that the test substance concentrations were satisfactorily maintained over the whole exposure period.

RESULTS: Using the water accommodated fractions significant effects (>1 0% immobilization) were observed at 8.83 mg/L (72.5%) and 8.91 mg/L (97.5%) with respect to the analytically determined concentration after 24 and 48 h of exposure, respectively.

No significant effects were observed at all other concentrations and in the control after 24 and 48 h of exposure.

Based on the analytically determined concentrations the 24 and the 48 h EC50 values of the test item are 7.25 mg/L (95% confidence

interval: 6.68- 7.85 mg/L) and the 6.42 mg/L (95% confidence interval: 5.62- 7.41 mg/L), respectively.

The no-observed-effect concentrations (NOEC) for 24 and 48 h of exposure are 4.68 mg/L and 4.71 mg/L with respect to the analytically determined concentrations.

Almost 100% immobilization was detected at 8.91 mg/L with respect to the analytically determined concentration after 48 h.

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