Reaction mass of 4,4,13,13-tetraethoxy-3,14-dioxa-8,9-dithia-4,13-disilahexadecane and 4,4,14,14-tetraethoxy-3,15-dioxa-8,9,10-trithia-4,14-disilaheptadecane

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2009-08-26 to 2009-11-19

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The study was conducted according to an appropriate OECD test guideline, and in compliance with GLP, and was considered to be reliability 1 (reliable without restrictions). Read across to the registered substance is considered scientifically justified; the read across is considered to be reliability 2.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Samples of the WAFs were taken after preparation and turbidity measurements made in order to assess whether they contained any undissolved test substance.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)

- Method: A WAF was prepared at a loading rate of 10 mg/L by means of magnetic stirring for 4 days followed by overnight settling. This resulted in a clear solution that also contained finely dispersed material. The dispersion was left to stabilise overnight after which the undissolved material was mainly present floating at the surface or as precipitate. The water phase was collected and centrifuged for 30 minutes at 10000 rpm (18480 g). The supernatant was collected with a pipette and used for testing.
- Controls: Dilution water

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM

- Source: In-house laboratory stock culture

- Age at study initiation (mean and range, SD): <24 hours

- Method of breeding: acyclical parthenogenesis

- Feeding during test: none


ACCLIMATION

- Acclimation period: continuous

- Acclimation conditions (same as test or not): same except that M7 medium was used for culture and adjusted ISO medium was used for the test.

- Feeding frequency: Daily with a suspension of algae

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

180 mg/L as CaCO3

Test temperature:

20.0-20.5ºC

pH:

7.6-7.8

Dissolved oxygen:

8.7-9.2 mg/L

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal loading rate: 0 (Control) and 10 mg/L

Details on test conditions:

TEST SYSTEM


- Test vessel:

- Type (delete if not applicable): open

- Material, size, headspace, fill volume: 100 mL with 80 mL of test medium

- Aeration: none

- Renewal rate of test solution: Daily

- No. of organisms per vessel: 5

- No. of vessels per concentration (replicates): 4

- No. of vessels per control (replicates): 4

- Biomass loading rate: 1 daphnid/16 mL of test medium


TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: Adjusted ISO medium prepared with reverse-osmosis treated water

- Culture medium different from test medium: yes

- Intervals of water quality measurement: Daily


OTHER TEST CONDITIONS
- Adjustment of pH: No

- Photoperiod: 16 hours light and 8 hours dark


EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Mobility after 24 and 48 hours


TEST CONCENTRATIONS

- Spacing factor for test concentrations: Limit test

- Range finding study
- Test concentrations: Loading rates of 1, 10 and 100 mg/L

- Results used to determine the conditions for the definitive study: Effects were demonstrated at 1, 10 and 100 mg/L but were attributed to the presence of undissolved test material.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOELR

Effect conc.:

>= 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Immobilisation in control: 10%

- Effect concentrations exceeding solubility of substance in test medium: The test media were WAFs that were prepared at a loading rate (10 mg/L) that exceeded the solubility of the substance.

Results with reference substance (positive control):

48 h EC50: 0.75 mg/L (95% confidence interval: 0.56-1.0 mg/L)

Reported statistics and error estimates:

No significant effects on mobility were observed in the test and therefore statistical analysis of the results was not required.

Table 1. Test results

Nominal loading rate (mg/L)	Percentage immobilisation after 24 hours	Percentage immobilisation after 24 hours
0 (Control)	5	10
10	0	0

UV/VIS spetral scans of the 10 mg/L test WAFs at 200 and 900 nm showed that they did not contain significant amounts of undissolved material.

Validity criteria fulfilled:

yes

Conclusions:

A 48-hour EL50 value of >10 mg/L and NOELR of ≥10 mg/L have been determined for the effects of the test substance on mobility of Daphnia magna.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1996-08-20 to 1996-10-11

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Guideline study with acceptable restrictions. The study was conducted according to an appropriate OECD test guideline, with acceptable restrictions. The restriction was that there was no analysis of exposure concentrations and it is likely that the solubility of the test substance was exceeded in the test. The read-across is considered to be reliability 2.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: A stock dispersion of the test substance was prepared by adding 10 mg of the test substance to 10 μL of ethanol in 10 mL of dilution water. Test media were then prepared by adding quantities of the stock dispersion to dilution water. The concentration of ethanol was then adjusted to be the same in each treatment.

- Controls: Dilution water and dilution water plus ethanol.

- Chemical name of vehicle (organic solvent, emulsifier or dispersant): ethanol

- Concentration of vehicle in test medium (stock solution and final test solution): 100 μL/L

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM

- Source: LWA Düsseldorf, Germany

- Age at study initiation (mean and range, SD): 6-24 hours

- Method of breeding: Laboratory stock culture

- Feeding during test: none

ACCLIMATION

- Acclimation conditions (same as test or not): no data

- Type and amount of food: no data

- Feeding frequency: no data

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

No data

Test temperature:

20ºC

pH:

7.4-8.3

Dissolved oxygen:

8.4-8.7 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

Nominal concentrations: 0(Control), 0+100 μl/l ethanol (vehicle control), 0.125, 0.25, 0.5, 1, 2, 4, 6, 8 and 10 mg/l

Details on test conditions:

TEST SYSTEM

- Test vessel: No data

- Type (delete if not applicable): covered to prevent entry of dust

- Fill volume: 100 ml

- Aeration: no

- Renewal rate of test solution: static test

- No. of organisms per vessel: 5

- No. of vessels per concentration (replicates): 4

- No. of vessels per control (replicates): 4

- No. of vessels per vehicle control (replicates): 4

- Biomass loading rate: 1 daphnid/20 mL

TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: Reconstituted fresh water prepared by adding salts to deionised water and stirring vigorously for 30 minutes.

- Culture medium different from test medium: no

- Intervals of water quality measurement: start and end of test

OTHER TEST CONDITIONS

- Adjustment of pH: no

- Photoperiod: no data

- Light intensity: no data

EFFECT PARAMETERS MEASURED: mobility after24 and 48 hours

TEST CONCENTRATIONS

- Spacing factor for test concentrations:
- Range finding study

- Test concentrations: 1, 10, 100 and 10000 mg/L

- Results used to determine the conditions for the definitive study: All immobile at 10 mg/l and none immobile at 1 mg/L.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: It is likely that undissolved material was present in the test media and could have contributed to observed effects.

Duration:

48 h

Dose descriptor:

NOELR

Effect conc.:

0.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Mortality of control: 0

- Other adverse effects control: none

- Effect concentrations exceeding solubility of substance in test medium: Some of the loading rates employed in the test exceeded the expected water solubility of the substance (1 mg/L).

Results with reference substance (positive control):

- Results with reference substance valid? yes

- EC50/LC50: 1.1-1.9 mg/L

Reported statistics and error estimates:

The EL50 values were determined from dose-response relationships plotted on probit paper. The NOELR values were determined directly from the raw data.

Table 1. Test results

 

Nominal concentration of test substance (mg/L)	Immobilisation after 24 hours (%)	Immobilisation after 48 hours (%)
Control	0	0
Control + ethanol	0	0
10	100	100
8	65	100
6	20	75
4	10	45
2	0	15
1	0	5
0.5	0	0
0.25	0	0
0.125	0	0

Validity criteria fulfilled:

yes

Remarks:

in respect of NOELR value

Conclusions:

A 48-h EL50 value of 4.0 mg/L and a NOELR of 0.5 mg/L have been determined for the effects of the test substance on mobility of Daphnia magna in the presence of ethanol as a vehicle. The EL50 value exceeds the expected water solubility of the substance (1 mg/l) and therefore it is possible that the presence of undissolved test material influenced the results.

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1998-09-24 to 1998-09-26

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

no

Analytical monitoring:

no

Details on sampling:

not applicable

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: 10 mg and 1 mg of the test substance were weighed onto a small polyethylene platelett. The plateletts were then transferred to 1 litre polyethylene bottles. The bottles were each filled with 1 litre of oxygen-saturated dilution water and sealed with a screw cap. They were then shaken for 20 hours at 20+/-1.5ºC before being allowed to settle for 4 hours. The resulting solutions were then transferred into four replicate 100 ml polyethylene test vessels. The vessels were sealed during the exposure period. Undissolved material was observed to be present in the exposure media prepared for both tests.

- Controls: Dilution water

- Evidence of undissolved material (e.g. precipitate, surface film, etc): the solubility of the test substance is noted as being in the order of 1 mg/l and therefore it is possible that undissolved test material was present at the highest loading rate.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM

- Source: Dr. Knie, LWA

- Age at study initiation (mean and range, SD): <24 hours

- Method of breeding: laboratory stock culture

- Feeding during test: none

ACCLIMATION

- Acclimation conditions: same as test

- Type and amount of food: green algae Scenedesmus subspicatus

- Feeding frequency: daily

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

no data

Test temperature:

21.0-21.4ºC

pH:

7.20-7.43

Dissolved oxygen:

7.5-8.0 mg/l

Salinity:

not applicable

Nominal and measured concentrations:

Nominal loading rates: 1 and 10 mg/l

Details on test conditions:

TEST SYSTEM

- Test vessel: flasks

- Type: closed

- Material, size, headspace, fill volume: polyethylene, 100 ml, no headspace, 100 ml

- Aeration: none
- Other: The test vessels were placed on a light table to discourage the test organisms from coming into contact with undissolved test substance on the surface of the test medium.

- Renewal rate of test solution (frequency/flow rate): static test

- No. of organisms per vessel: 5

- No. of vessels per concentration (replicates): 4

- No. of vessels per control (replicates): 4

- Biomass loading rate: 1 dahnid/20 ml test medium

TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: drinking water

- Culture medium different from test medium: no

- Intervals of water quality measurement: start and end of test

OTHER TEST CONDITIONS

- Adjustment of pH: no

- Photoperiod: 16 h light, 8 h dark

EFFECT PARAMETERS MEASURED: mobility after 24 and 48 hours

TEST CONCENTRATIONS

- Spacing factor for test loading rates: 10

- Justification for using less concentrations than requested by guideline: no data

- Range finding study: no data

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

< 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Microscopic examination of the test organisms exposed to both treatments showed evidence of physical fouling of the antennae with the test substance. The report authors attribute the observed immobility of the test organisms to this phenomenon.

Duration:

48 h

Dose descriptor:

NOELR

Effect conc.:

< 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Other biological observations: Microscopic examination of the test organisms exposed to both treatments showed evidence of physical fouling of the antennae with the test substance. The report authors attribute the observed immobility of the test organisms to this phenomenon.

- Mortality of control: 0

- Effect concentrations exceeding solubility of substance in test medium: The report authors note the presence of undissolved test material causing fouling of the test organisms.

Results with reference substance (positive control):

no data

Reported statistics and error estimates:

No statistical test were applied to the results

Table 1. Test results

Nominal test substance loading rate (mg/l)	Mean percentage immobilisation after 24 hours	Mean percentage immobilisation after 48 hours
0 (Control)	0	0
1	75	75
10	95	100

Validity criteria fulfilled:

yes

Conclusions:

A 48-h EL50 value of <1 mg/l and NOELR of <1 mg/l) have been determined for the effects of the test substance on mobility of Daphnia magna. It is likely that the observed effects on the test organisms resulted, at least in part, from exposure to undissolved test material that was seen to be present in the test media even though steps were taken to avoid it.

Description of key information

Short-term toxicity to invertebrates: 48-h EC₅₀ >10 mg/l (nominal) (highest concentration tested) (OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)), read across from an analogous/structurally related substance, polysulfides, bis[3-(triethoxysilyl)propyl] (CAS 211519-85-6).

Additional information

No data are available for short-term toxicity of the registration substance to aquatic invertebrates. This endpoint is therefore addressed by weight of evidence from data for related substances.

A 48-hour EL₅₀ value of >10 mg/l has been determined for the effects of polysulfides, bis[3-(triethoxysilyl)propyl] (CAS 211519-85-6) on mobility of Daphnia magna.

Results from tests that gave EL₅₀ values of <1 mg/l and 4.0 mg/l for 4,4,13,13-tetraethoxy-3,14-dioxa-8,9-dithia-4,13-disilahexadecane (CAS 56706-10-6) are likely to have been influenced by the presence of undissolved test material in the test media.

The 48-hour EL₅₀ value of >10 mg/l is considered to be the appropriate value for the registration substance.