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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:
14 July 2009 - 16 July 2009
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study under GLP, test substance could not be maintained in solution, all reasonable steps taken to maintain test substance concentration.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report date:
2009

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
GLP compliance:
yes

Test material

Constituent 1
Reference substance name:
MeDONA
IUPAC Name:
MeDONA
Details on test material:
- Name of test material (as cited in study report): MTDID #10078
- Physical state: clear colorless liquid
- Analytical purity: 91.9%
- Lot/batch no.: 140499-21/8
- Stability under test conditions: Hydrolytically unstable and likely to be volatile
- Storage condition of test material: At room temperature in the dark

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Sampling method: At 0h, 4.5 mL aliquots were taken from all test concentration and controls.
- Sample storage conditions before analysis: Not applicable, samples were analysed same day as sampling because MeDONA concentration were not stable during freezing and thawing of samples.

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The highest concentrations (loading rate of 100 mg/L) was prepared by spiking underneath the surface a volume of 63 µL test substance to 1L test medium. The aqueous solution was magnetically stirred for 18.5 hours in a closed glass vessel with minimal headspace in order to prevent any volatilization and to reach maximum solubility. The mixture was then stabilized for 1.25 hour and then the water accommodated fraction (WAF) was siphoned off. The lower test concentrations for the range-finding test were prepared by subsequent dilutions of the WAF in test medium.
- Controls: Test medium without test substance or other additives
- Evidence of undissolved material: The final test solutions were all clear and colorless.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Water flea
- Strain: Straus, 1820
- Source: In-house laboratory culture
- Age at study initiation (mean and range, SD): < 24 hours, from parental daphnids of more than 2 weeks old
- Method of breeding: Breeding batch started by placing approximately 250 daphnids less than 3 days old into 5 liters of M7 medium (modified ISO medium) in an all-glass culture vessel. Cultures maintained for a maximum age of 4 weeks. After the first 7 days, cultures are renewed by replacement of half of the medium twice weekly. Cultures are maintained at 18 - 22 °C and fed daily with a suspension of freshwater algae.
- Feeding during test: None

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h
Remarks on exposure duration:
Combined limit/range-finding test

Test conditions

Hardness:
180 mg CaCO3/L
Test temperature:
19.4 - 20.6 °C
pH:
7.5 - 7.8
Dissolved oxygen:
8.5 - 9.2
Nominal and measured concentrations:
Water accommodated fraction (WAF): 0.1, 1.0, 10 and 100% from a loading rate of 100 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: 100 mL, all-glass containers
- Aeration: None
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4 for 100% WAF; 2 for 0.1, 1.0 and 10% WAF
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Water used to make growth medium was tap water purified by Reverse Osmosis (RO-water, GEON Waterbehandeling, Berkel-Enschot, The Netherlands)
- Culture medium different from test medium: no, standard M7 medium used throughout. M7 is based on standard ISO medium supplemented with additional minerals.

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 h light; 8 h dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
-Immobilization (including mortality): At 24 hours and 48 hours

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10
- Range finding study: Yes, test was a combined limit/range-finding test
Reference substance (positive control):
yes
Remarks:
Potassium dichromate (K2Cr2O7)

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
Remarks on result:
other: The EC50 result corresponds to a 100% water accommodated fraction of MeDONA (loading rate of 100 mg/L).
Details on results:
Concentrations at beginning of test are shown in Table 1. Immobilization data shown in Table 2.

- Mortality of control: None
- Other adverse effects control: None
- Abnormal responses: None
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: None
- Effect concentrations exceeding solubility of substance in test medium: yes
- Other: The response of the test samples was smaller than the least concentrated (0.10 mg/L) procedural recovery sample. Concentrations were therefore reported as <0.1 mg/L
Results with reference substance (positive control):
The 48-hr EC50 for potassium dichromate was 0.75 mg/L with a 95% confidence interval of 0.56 - 1.0 mg/L. This result was within the historical range for this laboratory. Hence, the sensitivity of this batch of D. magna was in agreement with the historical data collected at NOTOX.
Reported statistics and error estimates:
No EC50 could be calculated because the test substance proved to be non-toxic (EC50 > maximum soluble concentration).

Any other information on results incl. tables

Table 1 Concentrations of MeDONA in test medium at sampling time 0 hours.

Percentage of WAF ¹
(%)

Analyzed ²
(mg/L)

0

< 0.1

0

< 0.1

0.1

< 0.1

0.1

< 0.1

1.0

< 0.1

1.0

< 0.1

10

< 0.1

10

< 0.1

100

< 0.1

100

< 0.1

1) A water accommodated fraction (WAF) was prepared at the loading rate of 100 mg/L and diluted to make the test solutions

2) The response of the test samples was smaller than the responses of the 0.1 mg/L procedural recovery samples

Table 2 Acute immobilization of daphnids after 24 and 48 hours

Test group
MeDONA
(% WAF)¹

Vessel
ID

Number of daphnid exposed

Response
at 24h

Response
at 48h

No.

Total
%

No.

Total
%

Control

A

5

0

0

0

0

B

5

0

0

C

5

0

0

D

5

0

0

0.1

A

5

0

0

0

0

B

5

0

0

1.0

A

5

1

10

1

10

B

5

0

0

10

A

5

0

0

0

0

B

5

0

0

100

A

5

0

0

0

5

B

5

0

1

C

5

0

0

D

5

0

0

1) Test groups represent percentages of a WAF prepared at 100 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
No immobilization in controls, dissolved oxygen ≥ 3 mg/L
Conclusions:
The 48-hour EC50 of MeDONA to Daphnia magna was >100 mg/L (OECD 202), based on the 100% water accommodated fraction of MeDONA (loading rate of 100 mg/L).
Executive summary:

The 48-hour EC50 of MeDONA for mobility is > 100 mg/L, corresponding to the 100% Water Accommodated Fraction (WAF). MeDONA did not induce acute immobilization of Daphnia magna at any of the WAF percentages tested. Concentration levels that might have been toxic for Daphnia magna could not be reached due to the behavior of MeDONA in water (low solubility, volatile and subject to hydrolysis). This study is considered reliable with restrictions due to the unstable nature of the compound. The study was performed in accordance with internationally-accepted test guidelines and Good Laboratory Practice (GLP) standards. Therefore, the results are suitable for purposes of Risk Assessment, Classification & Labeling, and PBT Analysis.

Test Type: Static

48-h EC50: >100 mg/L

The EC50 results correspond to a loading rate of 100 mg/L MeDONA.