Tetramethylcyclotetrasiloxane substituted dipropylether bisphenol A

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:

Experimental dates: 04 December 2020 to 12 August 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2022

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

2008

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of (Tetramethylcyclotetrasiloxane propylether) prop-1-enylether bisphenol A and Di(tetramethylcyclotetrasiloxane propylether) bisphenol A

Cas Number:

203874-34-4

Molecular formula:

(OSiHxCH3)4-CH2-CH2 -CH2- O-C6H4-C(CH3)2-C6H4-0-CH2-CH2-CH2-(SiHxCH3O)4

IUPAC Name:

Reaction mass of (Tetramethylcyclotetrasiloxane propylether) prop-1-enylether bisphenol A and Di(tetramethylcyclotetrasiloxane propylether) bisphenol A

Test material form:

liquid

Details on test material:

Appearance: Pale yellow liquid

Specific details on test material used for the study:

Storage Conditions: Room temperature in the dark under nitrogen

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples were taken from the control and the 100 mg/L loading rate WAF test group from the bulk test preparation at 0 hours, which were stored refrigerated prior to analysis and from the pooled replicates (Replicates 1 to 4) at 48 hours, which were sent for immediate quantitative analysis.

Test solutions

Vehicle:

no

Details on test solutions:

Based on the results of the range-finding test a "limit test" was conducted at a loading rate of 100 mg/L to confirm that at the maximum concentration given in the OECD/EC Test Guidelines no significant immobilization was observed.
A nominal amount of test item (200 mg) was added to the surface of 2 L of test water to give the 100 mg/L loading rate. After the addition of the test item, the test water was stirred by magnetic stirrer using a stirring rate such that a vortex was formed to give a dimple at the water surface. The stirring was stopped after 23 hours and the mixture allowed to stand for 1 hour.
Visual observations made on the WAF showed dispersed test item to be present and hence it was considered justifiable to remove the WAF by filtering through a glass wool plug. Microscopic examination of the WAF after filtering showed there to be no micro-dispersions of test item present.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnids
- Method of breeding: Culture conditions ensured that reproduction was by parthenogenesis. Gravid adults were isolated the day before initiation of the test, such that the young daphnids produced overnight were less than 24 hours old. These young were removed from the cultures and used for testing.
- Source: In-house laboratory cultures.
- Feeding during test: Each culture was fed daily with a mixture of algal suspension (Raphidocelis subcapitata) and GEMMA Micro 300 fish food suspension.

Study design

Test type:

static

Water media type:

freshwater

Remarks:

Reconstituted water (Elendt M4)

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Test temperature:

20- 21 ºC

pH:

8.2 - 8.4

Dissolved oxygen:

8.7 - 8.9 mg O2/L

Nominal and measured concentrations:

Nominal: 100 mg/L (Based on the results of the range-finding test a "limit test" was conducted at a loading rate of 100 mg/L to confirm that at the maximum concentration given in the OECD/EC Test Guidelines no significant immobilization was observed.)

Measured: Total Organic Carbon (TOC) was used to monitor the exposure concentrations during the definitive test. TOC analysis of the 100 mg/L loading rate WAF preparations showed a measured concentration of 0.39 mg/L C/L at 0 hours and 0.19 mg/L C/L at 48 hours.
Given that toxicity cannot be attributed to a single component or a mixture of components, but to the test item as a whole, the results were based on nominal loading rates only.

Details on test conditions:

As in the range-finding test 150 mL vessel containing approximately 100 mL of test preparation were used. At the start of the test five daphnids were placed in each test and control vessel at random, in the test preparations. Four replicate test and control vessels were prepared. The test vessels were then covered to reduce evaporation and maintained in a temperature controlled room maintaining the water temperature at 18 to 22°C with a maximum deviation of ±1 °C with a photoperiod of 16 hours light (between 200 and 1200 lux) and 8 hours darkness with 20 minute dawn and dusk transition periods. The daphnids were not individually identified, received no food during exposure and the test vessels were not aerated.
The control group was maintained under identical conditions but not exposed to the test item

Reference substance (positive control):

yes

Remarks:

A positive control test using potassium dichromate as the reference item was performed twice in a 12 month period to demonstrate satisfactory conditions of the test.

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

There was no immobilization in 20 daphnids exposed to a 100 mg/L loading rate WAF for a period of 48 hours. A single immobilized daphnid was observed in the control group after 48 hours exposure. Trapping at the surface was observed in the control group at 24 hours only. No sub-lethal effects of exposure were observed in the test group throughout the test.
It was considered unnecessary and unrealistic to test at concentrations in excess of 100 mg/L.

At the start of the mixing period the 100 mg/L preparation was observed to have formed a clear colorless water column with a slick of test item at the surface. After 23 hours stirring the 100 mg/L preparation was observed to have formed a clear colorless water column with a slick of test item at the surface and small brown particles dispersed throughout. After a 1-Hour standing period small brown particles were visible settled at base of the vessel. As visual inspection of the WAF showed dispersed test item to be present, the WAF was removed by filtration through a glass wool plug (the first 75 mL was discarded). Microscopic examination of the WAF after filtering showed there to be no micro-dispersions of test item present.
During the test the control and 100 mg/L loading rate WAF preparations were observed to be clear, colorless solutions.

TOC analysis of the 100 mg/L loading rate WAF preparations showed a measured concentration of 0.39 mg/L C/L at 0 hours and 0.19 mg/L C/L at 48 hours. The dissolved test item may have been one or several components of the test item. Given that toxicity cannot be attributed to a single component or a mixture of components, but to the test item as a whole, the results were based on nominal loading rates only.

Results with reference substance (positive control):

The results from the positive control with potassium dichromate were within the normal range for this reference item (EC50(48 h):0.50 mg/L, NOEC:0.32 mg/L).

Any other information on results incl. tables

The test was considered to be valid given that no more than 10% of the control daphnids showed immobilization or other signs of disease or stress and that the oxygen concentration at the end of the test was equal to or greater than 3 mg/L in the control and test vessels.

 

Results range-finding test

One Daphnia treated at a concentration of 10 mg/L loading rate WAF was observed to be trapped at the surface after 24 hours exposure.
Based on this information a single loading rate of four replicates of 100 mg/L loading rate WAF, was selected for the definitive test. This experimental design conforms to a "Limit test" to confirm that no significant immobilization was observed.

Chemical analysis of the test preparations at 0 and 48 hours showed measured test concentrations of less than the LOD of the analytical method employed were obtained. This does not infer that no test item was in solution, just that any dissolved test item was at a concentration of less than the LOD.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test item to the freshwater invertebrate Daphnia magna was investigated following OECD/EC guidelines and gave a 48-Hour NOEL of 100 mg/L loading rate WAF.

Executive summary:

A study was performed to assess the acute toxicity of the test item to Daphnia magna, according to OECD Guideline 202 and GLP principles.

Due to the low aqueous solubility and complex nature of the test item, for the purposes of the test, the test medium was prepared as a Water Accommodated Fraction (WAF).
Following a preliminary range-finding test, 20 daphnids (4 replicates of 5 animals) were exposed to a Water Accommodated Fraction (WAF) of the test item at a nominal loading rate of 100 mg/L for 48 hours at a temperature of approximately 20°C to 21°C under static test conditions. Immobilization and any adverse reactions to exposure were recorded after 24 and 48 hours.

Total Organic Carbon (TOC) was used to monitor the exposure concentrations during the definitive test as no test item was detectable in samples from the preliminary test and the analytical method could not be optimized. TOC analysis of the 100 mg/L loading rate WAF preparations showed a measured concentration of 0.39 mg/L C/L at 0 hours and 0.19 mg/L C/L at 48 hours.
Given that toxicity cannot be attributed to a single component or a mixture of components, but to the test item as a whole, the results were based on nominal loading rates only.
Exposure of Daphnia magna to the test item gave EL50 values of greater than 100 mg/L loading rate WAF. The No Observed Effect Loading (NOEL) rate was 100 mg/L loading rate WAF.
It was considered unnecessary and unrealistic to test at concentrations in excess of 100 mg/L.