Registration Dossier

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:
28 November 2018 - 11 January 2019
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2019
Report Date:
2019

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)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
- Name of test material (as cited in study reports): 1,4-dioxan-2-one (PDO monomer)
- Physical state: solid (powder)
- Appearance: white powder
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: YRMC196
- Expiration date of the lot/batch: 24 January 2019
- Purity test date: 12 September 2018

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: in refrigerator, 2-8°C
- Solubility and stability of the test substance in the solvent/vehicle: test substance is completely soluble in test medium at the concentrations tested



Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations:
10, 18, 32, 56, 100 mg/L + control
At the end of the exposure period, the replicates were not pooled at each concentration before sampling. Instead, samples were taken from one replicate per treatment.

- Sampling method:
Samples for possible analysis were taken from all test concentrations and the control according to the following schedule:
Frequency at t=0 h and t=48 h
Volume 4.0 mL from the approximate centre of the test vessel

- Sample storage conditions before analysis:
Not applicable, samples were transferred to the analytical laboratory at the Test Facility and analysed on the day of sampling.

Test solutions

Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Preparation of test solutions started with the highest concentration of 100 mg/L. No other treatment than vigorous shaking was needed to completely dissolve the test item in medium. Lower test concentrations were prepared by subsequent dilutions of the highest concentration in test medium. All test solutions were clear and colorless at the end of the preparation procedure.

- Eluate:
- Differential loading:
- Controls:
- Chemical name of vehicle (organic solvent, emulsifier or dispersant):
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)):
- Evidence of undissolved material (e.g. precipitate, surface film, etc.):
- Other relevant information:

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: water flea
- Strain/clone: at least third generation, obtained by a cyclical parthenogenesis under specified breeding conditions
- Source: in-house laboratory culture with a known history
- Age of parental stock (mean and range, SD): young daphnia with an age of < 24 hours from parental daphnids of more than two weeks old
- Method of breeding: 250 newborn daphnids (i.e. less than 3 days old) are placed into 5 liters of medium in an all-glass culture vessel. Medium is M7. After 7 days of cultivation half of the medium is renewed twice a week.
- Feeding during cultivation: fresh water algae, daily
- Feeding during test: no



Study design

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

Test conditions

Hardness:
180 mg/L CaCO3
Test temperature:
19-20°C
pH:
Start (t=0h): 8 (mean)
End (t=48h): 8.6 (mean)
Dissolved oxygen:
Start (t=0h): 9.4 mg/L O2 (mean)
End (t=48h): 8.6 mg/L O2 (mean)
Salinity:
not applicable
Conductivity:
not applicable
Nominal and measured concentrations:
Range-finding test:
Nominal concentrations: 0.1, 1.0, 10, 100 mg/L
Measure concentrations (t=0h): *, 0.36, 5.1, 76 mg/L
Measured concentrations (t=48h): *, *, *, 1.6 mg/L
* not detected

Final test:
Nominal concentrations: 10, 18, 32, 56, 100 mg/L
Measure concentrations (t=0h): 4.1, 9.9, 17, 36, 67 mg/L
Measured concentrations (t=48h): *, *, *, 0.18, 1.9 mg/L
* not detected
Details on test conditions:
TEST SYSTEM
- Test vessel: glass vessel
- Type (delete if not applicable): open / closed
- Material, size, headspace, fill volume: glass vessels
- Aeration: no aeration of the test solutions
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: 16 hours photoperiod daily

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immoblity, defined as those animals not able to swim within 15 seconds after gentle agitation of the test vessel and was monitored after 24 and 48 hours of continuous treatment with the test substance.

TEST SYSTEM
- Test vessel: glass vessel
- Type: closed
- Material, size, headspace, fill volume: 50 mL all glass airtight closed without headspace
- Volume of solution: 50 mL
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 20
- No. of vessels per control (replicates): 4


TEST MEDIUM / WATER PARAMETERS
The following salts (analytical grade) were added to tap water purified by Reverse Osmosis (RO-water, GEON Waterbehandeling, Berkel-Enschot, The Netherlands):
CaCl2.2H2O 211.5 mg/L
MgSO4.7H2O 88.8 mg/L
NaHCO3 46.7 mg/L
KCl 4.2 mg/L
The hardness of test medium expressed as CaCO3: 180 mg/L with a pH between 6 and 9.


OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: daily photoperiod of 16 hours


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

RANGE-FINDING STUDY
- Test concentrations: 0.1, 1, 10, 100 mg/L
- Results used to determine the conditions for the definitive study: yes
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrations
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
5.3 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% confidence interval: 2.5-11 mg/L
Details on results:
- Mortality of control: no
- Immobilisation of control: no
- Abnormal responses: none indicated
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values:
- Effect concentrations exceeding solubility of substance in test medium: no
Reported statistics and error estimates:
The 24h-EC50 could not be determined because the observed effects were below 50%.

The 48h-EC50 could not be determined using a regression method. This was because there was no concentration between the highest concentration (A) at which 0% immobility and the lowest concentration (B) at which 100% immobility occurred. Instead, the EC50 was calculated as (AB)½, with A and B being limits of the 95% confidence interval.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The acute toxicity of PDO monomer to Daphnia magna was determined in a 48 hour static test according to OECD guideline 202. the EC50-48h value with respect to immobilization is 5.3 mg PDO monomer per litre. The results of the test can be considered reliable without restriction.