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Ecotoxicological information

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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP compliant guideline study, available as unpublished report, no restrictions, fully adequate for assessment.
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Concentrations: 100 mg/L
- Sample storage conditions before analysis: direct analysis
Vehicle:
no
Details on test solutions:
Test sample was precisely weighed with an electronic balance and dissolved in dilution water in a closed bottle to produce 100 mg/L (nominal concentration), then stirred for 48 hours. The suspension was left to rest 1 hour prior to start of the test. The solution was collected from the middle layer for use as test solution.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Strain: Clone A
- Source: laboratory culture
- Age at study initiation (mean and range, SD): < 24 h
- Method of breeding: same as test conditions
- Feeding during test: no
Test type:
semi-static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h
Test temperature:
19.8 to 20.0 ºC
pH:
7.7 to 7.8
Dissolved oxygen:
8.4 to 8.5 mg/L
Nominal and measured concentrations:
Nominal: 100 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: Petri dish (I.D. of 8.0 cm, depth of 5.0 cm)
- Type (delete if not applicable): closed with a glass cover
- Material, size, headspace, fill volume: 250 mL test volume (no headspace)
- Aeration: no
- Renewal rate of test solution (frequency/flow rate): after 24 hours
- 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: dechlorinated tap water, aerated sufficiently

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): immobilisation

TEST CONCENTRATIONS
- Justification for using less concentrations than requested by guideline: based on the results of preliminary studies, it was expected that the test solution at around the solubility in dilution water had no effect on the test organisms. Therefore the definitive study was conducted as a limit test with a nominal concentration of 100 mg/L which was prepared by stirring for about 48 hours.
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Duration:
48 h
Dose descriptor:
EL50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 0.144 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: effect concentration is larger than the water solubility
Details on results:
None of the animals died during the exposure period
Results with reference substance (positive control):
- Results with reference substance valid? yes
- EC50: 0.283 mg/L
Validity criteria fulfilled:
yes
Conclusions:
The EL50 value is >100 mg/L, and the corresponding 48-h EC50 value >0.144 mg/L. This effect concentration is larger than the water solubility.
Executive summary:

In a GLP-compliant OECD 202 guideline study with Daphnia magna, daphnids (20/dose) were exposed to a nominal concentration of 100 mg/L under semi-static conditions for 48 hours; the test concentration was analytically verified by GC-MS and was less then 80% of nominal concentrations. The test concentration was prepared by stirring the test solution with a target dose level of 100 mg/L for 48 hours before exposure. None of the daphnids were immobilised at the end of the exposure period. The EL50 value is >100 mg/L, and the corresponding 48-h EC50 value >0.144 mg/L. This effect concentration is larger than the water solubility.

Description of key information

The 48-h EC50 value of AC-6000 in Daphnia magna is >0.144 mg/L; this value will be used in the assessment.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
0.144 mg/L

Additional information

A GLP-compliant OECD 202 guideline study with Daphnia magna is available for AC-6000 (Kurume Laboratory, 2007b). Daphnids (20/dose) were exposed to a nominal concentration of 100 mg/L under semi-static conditions for 48 hours; the test concentration was analytically verified by GC-MS and was less then 80% of nominal concentrations. The test concentration was prepared by stirring the test solution with a target dose level of 100 mg/L for 48 hours before exposure. None of the daphnids were immobilised at the end of the exposure period. The EL50 value is >100 mg/L, and the corresponding 48-h EC50 value >0.144 mg/L. This effect concentration is larger than the water solubility.

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