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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
26 - 29 Jan 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016
Report Date:
2016

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Health Care Inspectorate of the Ministry of Health, Welfare and Sport, Utrecht, The Netherlands

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Ethyl ascorbic acid
- Physical state: powder
- Expiration date of the lot/batch: 21 Apr 2018
- Stability under test conditions: stable
- Storage condition of test material: in freezer at < -15 °C desiccated

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: control, 0.1, 1.0, 10, 100 mg/L
- Sampling method: Samples were taken after 0 and 48 h. 2 mL were taken from the approximate centre of the test vessels.
- Sample storage conditions before analysis: Samples taken at the beginning of the study were stored in a freezer until analysis whereas samples taken at the end of the study were analysed immediately. At the end of exposure, the replicates were pooled at each concentration before sampling. Additionally, reserve samples of 2.0 mL were taken for possible analysis. If not used, these samples were stored in a freezer for a maximum of three months.

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The highest test concentration of 100 mg/L was prepared by adding appropriate amount of the test substance to test medium followed by vigorous mixing. The lower concentrations were prepared by subsequent dilution of this stock solution.
- Eluate: no
- Differential loading: no
- Controls: yes, test medium control

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: water flea
- Source: in-house culture with a known history
- Age at study initiation (mean and range, SD): < 24 h (from parental daphnids of more than two weeks old)
- Method of breeding: With newborn daphnids, i.e. less than 3 days old, by placing about 250 of them into 5 litres of medium in an all-glass culture vessel. The culture was 4 weeks old (maximum). Cultures were renewed after 7 d of cultivation (half of the medium). Daphnids were fed with a suspension of freshwater algae. The medium was M7 medium
- Feeding during test: none

Study design

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

Test conditions

Test temperature:
19 - 20 °C
pH:
8.1 - 8.2 (control)
7.2 - 7.8 (highest test concentration)
Dissolved oxygen:
8.9 - 9.7 mg O2/L
Nominal and measured concentrations:
nominal: control, 0.1, 1.0, 10, 100 mg/L
measured: < LOQ, 0.068, 0.80, 7.8, 78 mg/L (average)
Details on test conditions:
TEST SYSTEM
Test vessel
- Material, size, headspace, fill volume: glass, 100 mL, headspace: 20 mL, fill volume: 80 mL
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 2 (for 0.10, 1.0 and 10 mg/L), 4 (for 100 mg/L)
- No. of vessels per control (replicates): 5

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to guideline
- Culture medium different from test medium: same as test
- Intervals of water quality measurement: The pH and dissolved oxygen at control and 100 mg/L were measured at the beginning and end of exposure whereas temperature was measured continuously.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light / 8 h dark

EFFECT PARAMETERS MEASURED
- Mobility: after 24 and 48 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10
Reference substance (positive control):
yes
Remarks:
potassium dichromate (tested in a separate study in December 2015)

Results and discussion

Effect concentrations
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 78 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
- Mortality of control: 0%
- Effect concentrations exceeding solubility of substance in test medium: no
Results with reference substance (positive control):
- Results with reference substance valid? yes
- EC50/LC50: EC50 (48 h): 0.38 mg/L (95% CI: 0.33 - 0.43 mg/L)
Reported statistics and error estimates:
No statistical analysis of the data were performed since no effects were observed in order to derive an EC50 value.

Any other information on results incl. tables

Table 1: Measured concentrations

Nominal concentration [mg/L]

Measured at t=0 h [mg/L]

Measured at t=48 h [mg/L]

Average concentration (geometric mean) [mg/L]

0.10

0.077

0.060

0.068

1.0

0.87

0.78

0.80

10

7.5

8.1

7.8

100

74

82

78

Applicant's summary and conclusion

Validity criteria fulfilled:
yes