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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:
16 March-24 April 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
2-ethylhexyl 12-hydroxyoctadecanoate
EC Number:
249-793-7
EC Name:
2-ethylhexyl 12-hydroxyoctadecanoate
Cas Number:
29710-25-6
Molecular formula:
C26H52O3
IUPAC Name:
2-ethylhexyl 12-hydroxyoctadecanoate
Test material form:
other: oil
Details on test material:
a-ethyl-hexyl-oxystearate
Specific details on test material used for the study:
Lot number: A9859
DOM: July 5th 2016

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
yes
Details on test solutions:
The batch of the test soultion tested was a clear yellowish liquid UVCB which was not completely soluble in test medium at the loading rates initially prepared. No correction was made for the purity/composition of the test item.
Preparation of test solutions started with loading rates individually prepared at 1.0, 10 and 100 mg/L. A two-day period of magnetic stirring was applied to ensure maximum dissolution of the test item in medium. The obtained mixtures were allowed to settle for an overnight period. Thereafter, the aqueous Water Accommodated Fractions (WAFs) were collected by means of siphoning and used as test concentrations. All test solutions were clear and colorless at the end of the preparation procedure.
Any residual volumes were discarded.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
Species Daphnia magna (Crustacea, Cladocera) (Straus, 1820), at least third generation, obtained by a cyclical parthenogenesis under specified breeding conditions.
Source In-house laboratory culture with a known history.
Reason for selection This system has been selected as an internationally accepted invertebrate species.
Validity of batch Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discoloured animals and there was no delay in the production of the first brood.
Characteristics For the test selection of young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h

Test conditions

Hardness:
180 mg/L expressed as CaCO3
Test temperature:
19-20°C
pH:
8.0-8.2
Dissolved oxygen:
8.8- 9.1 mg/l
Reference substance (positive control):
yes

Results and discussion

Effect concentrations
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 0.013 mg/L
Nominal / measured:
nominal
Conc. based on:
other: WAF
Basis for effect:
mobility
Details on results:
Samples taken from all test concentrations and the control were analysed. No detectable test item was measured in the samples taken from the WAFs prepared at loading rates of 1.0 and 10 mg/L. For the WAF prepared at a loading rate of 100 mg/L, the measured concentration at the start of the test was 0.12 mg/L. During the 48-hour exposure period, this concentration decreased to 0.0015 mg/L, i.e. was at 1.3% of initial at the end of the test. The decrease was thought to be due to the fact that the initial concentration was still above the solubility limit, which was which was strengthened by the presence of undissolved material after 24 hours. It should be noted that a small response was measured in the control which was, however, considered negligible. Based on these results, the average exposure concentration at the limit concentration was calculated to be 0.013 mg/L.
No immobility or other effects were observed in the control and at the WAF prepared at a loading rate of 10 mg/L throughout the test. At the end of the test, 40% and 30% immobility was observed at the WAFs prepared at 1.0 and 100 mg/L, respectively. A floating layer of undissolved material was observed at the limit concentration after 24 hours of exposure, which probably caused 75% of the daphnids to be trapped at the surface of the medium. At the end of the test, no floating layer was observed. Additionally, no daphnids were trapped at the surface of the medium and microscopic observation revealed no test item attached to the daphnids.
Results with reference substance (positive control):
The 24h-EC50 was 0.80 mg/L with a 95% confidence interval between 0.71 and 0.90 mg/L.
The 48h-EC50 was 0.33 mg/L with a 95% confidence interval between 0.29 and 0.38 mg/L.

Any other information on results incl. tables

Number of Introduced Daphnids and Incidence of Immobility in the Final Test

Time (h)

Replicate

WICKENOL 171; Loading rate (mg/L)

Control

1.0

10

100 [0.013]

0

A

5

5

5

5

B

5

5

5

5

C

5

 

 

5

D

5

 

 

5

Total introduced

20

10

10

20

24

A

0

0

0

1(4)

B

0

0

0

0(3)

C

0

 

 

1(3)

D

0

 

 

4(5)

Total immobilised

0

0

0

6

Effect %

0

0

0

30

 

 

 

 

48

A

0

1

0

1

B

0

3

0

0

C

0

 

 

1

D

0

 

 

4#

Total immobilised

0

4

0

6

Effect %

0

40

0

30

( ) – Number of daphnids observed trapped at the surface of the test solutions. These organisms were reimmersed into the respective solutions before recording of mobility.

[ ] – Average exposure concentration (mg/L).

# – Microscopic observation revealed no test item attached to the daphnids. 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
In conclusion, the 48h-EC50 for Daphnia magna exposed to WICKENOL 171 was beyond the range of concentrations tested, i.e. exceeded the average exposure concentration of 0.013 mg/L prepared at a loading rate of 100 mg/L as measured in a WAF prepared at a loading rate of 100 mg/L.
Executive summary:

In conclusion, the 48h-EC50for Daphnia magna exposed to WICKENOL 171 was beyond the range of concentrations tested, i.e. exceeded the average exposure concentration of 0.013 mg/L prepared at a loading rate of 100 mg/Las measured in a WAF prepared at a loading rate of 100 mg/L.