11-oxahexadecan-16-olide

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:

The study was conducted between 27 July 2017 and 3 November 2017.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

11-oxahexadecan-16-olide

EC Number:

222-225-5

EC Name:

11-oxahexadecan-16-olide

Cas Number:

3391-83-1

Molecular formula:

C15H28O3

IUPAC Name:

1,7-dioxacycloheptadecan-8-one

Test material form:

liquid

Specific details on test material used for the study:

Lot No.: VE00497116
Aspect: colourless liquid, may crystallize
Purity: 98.9%

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

The test item concentration in the test samples was determined by high performance liquid chromatography with UV detection (HPLC/UV) using external calibration. The test item gave a chromatographic profile consisting of one peak.

Test solutions

Vehicle:

yes

Remarks:

Acetonitrile

Details on test solutions:

Due to the low water solubility of the test item, the test media were prepared as follows: The test item was mixed into the test water at a loading rate of 100 mg/L, and was intensively stirred for 24 hours. After stirring the suspension was filtered through a 0.45 μm membrane filter. The undiluted filtrate and the dilutions 1:2, 1:4, 1:8 and 1:16 of the filtrate were used as test media. Additionally, a control (test water without test item) was tested in parallel. The preparation of the test media was based on the OECD Guidance Document No. 23 on Aquatic Toxicity Testing of Difficult Substances and Mixtures, 2000.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Test System
The study was performed with young daphnids of the species Daphnia magna Straus. A clone of this species (originally from the Daphnia Collection of the University of Basel/Switzerland in 2015) is successfully bred in IES Ltd Laboratories. The cultivation of the parental daphnids is performed in reconstituted water of the quality identical to the water quality used in the tests (with respect to pH, main ions, and total hardness) and under temperature and light conditions identical to those of the tests (see below).
During breeding, daphnids were generally fed three times a week with an algal suspension of the green algae Desmodesmus subspicatus, supplied by the Collection of Algal Cultures (SAG, Institute for Plant Physiology, University of Göttingen, 37073 Göttingen/Germany) and cultivated at IES Ltd Laboratories under standardized conditions or a mixture of this algal suspension and a commercial fish diet (Tetra Min® Hauptfutter, supplied by TETRA-Werke, 49324 Melle/Germany).
At the start of the test, the organisms used in the test were 6-24 hours old and were not first brood progeny.
For evaluation of the quality of the daphnia clone and the experimental conditions, potassium dichromate is tested as a positive control twice a year. The result of the latest positive control test in March 2017 (24-hour EC50: 1.2 mg/L, IES Laboratories Study 20170076) showed that the sensitivity of the test organisms was within the range given by the guideline (24-hour EC50:0.60-2.1 mg/L).

Study design

Test type:

semi-static

Water media type:

other: Reconstituted test water (ISO Test water) according to OECD Guideline No. 202 was used in the study.

Total exposure duration:

48 h

Test conditions

Test temperature:

20-22 °C

pH:

7.6 - 7.9

Dissolved oxygen:

At least 8.0 mg/L

Nominal and measured concentrations:

The concentrations determined in the freshly prepared test sample of day 0 were 7.61 mg/L (dilution 1:4), 12.9 mg/L (dilution 1:2) and 28.0 mg/L (undiluted). The concentrations determined in the freshly prepared test sample of day 1 were 7.27 mg/L (dilution 1:4), 12.8 mg/L (dilution 1:2) and 26.8 mg/L (undiluted). The measured concentrations reflect the dilution factors.
The concentrations determined in the test samples taken from the 24 hours aged test media of day 1 were 2.98 mg/L (dilution 1:4), 6.77 mg/L (dilution 1:2) and 10.2 mg/L (undiluted). The concentrations determined in the test samples taken from the 24 hours aged test media of day 2 were 4.59 mg/L (dilution 1:4) and 10.2 mg/L (dilution 1:2). It represents a decrease to 36 to 79 % of the corresponding starting concentration.

Details on test conditions:

Study Design for Main Test.
Based on the results of the stirring experiment and the range-finding test and in agreement with the Sponsor, the following concentrations of MUSK R1 were selected for the main test: The undiluted filtrate with a loading rate of 100 mg/L and the dilutions 1:2, 1:4, 1:8 and 1:16. Additionally, a control (test water without test item) was tested in parallel. The main test was performed in a closed system. Based on the analytical results of the pre-experiment, a semi-static main test with test medium renewal after 24 hours was chosen to keep the concentration as constant as possible during the test period of 48 hours. After 24 hours, the test organisms were transferred by wide-bore pipette in to clean test vessels with freshly prepared test medium of the corresponding concentration.

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

13.3 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CI :10.4 - 16.9 mg/L

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

10.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

16.9 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 4

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

13.3 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 5

Duration:

24 h

Dose descriptor:

EC0

Effect conc.:

10.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 6

Duration:

24 h

Dose descriptor:

EC100

Effect conc.:

16.9 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Results with reference substance (positive control):

For evaluation of the quality of the daphnia clone and the experimental conditions, potassium dichromate is tested as a positive control twice a year. The result of the latest positive control test in March 2017 (24-hour EC50: 1.2 mg/L, IES Laboratories Study 20170076) showed that the sensitivity of the test organisms was within the range given by the guideline (24-hour EC50: 0.60-2.1 mg/L).

Any other information on results incl. tables

Validity criteria:

The test is considered to be valid, as in the control no daphnids showed immobilization or other signs of disease or stress (e.g., discolouration or unusual behaviour such as trapping at the surface of water). Furthermore, the dissolved oxygen concentration at the end of the test was ≥3 mg/L in all test vessels.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Based on the mean measured concentrations of the test item, the 24-hour and 48-hour EC50 for Daphnia magna was 13.3 mg/L (95% confidence limits: 10.4 - 16.9 mg/L).

Executive summary:

The acute toxicity of the test item MUSK R1 to Daphnia magna was determined in a 48-hour test according to the OECD Guideline for Testing of Chemicals, No. 202 (2004) and the Commission Regulation (EC) No. 440/2008, Part C.2.

Based on the mean measured concentrations of the test item, the 24-hour and 48-hour EC50 for Daphnia magna was 13.3 mg/L (95% confidence limits: 10.4 - 16.9 mg/L).