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

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The study was carried out in accordance with an appropriate OECD test guideline, with restrictions, and in compliance with GLP.The restrictions were that a mixture of HCO20 and HC040 was used as dispersant, and the concentrations of the test substance were above the predicted water solubility. In addition, the analysis was performed by AA for Si and so it was not possible to determine whether parent or degradation product was measured.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 305 C (Bioaccumulation: Test for the Degree of Bioconcentration in Fish)

GLP compliance:

yes

Radiolabelling:

no

Details on sampling:

- Sampling intervals/frequency for test organisms: 2 fish per test concentration in weeks 2, 4, 6 and 8

- Sampling intervals/frequency for test medium samples: One sample per test concentration, twice per week

- Sample storage conditions before analysis: Not stated

Vehicle:

yes

Details on preparation of test solutions, spiked fish food or sediment:

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

- Method: Dispersion

- Controls: Vehicle control

- Chemical name of vehicle: Mixture of HCO20 and HCO40.

- Concentration of vehicle in test medium (stock solution and final test solution(s) at different concentrations and in control(s)):

Level 1 Stock Solution:

Test substance, 20 times its volume of HCO20 and 10 times its volume of HCO40 were mixed then deionised water was added to obtain a nominal concentration of 400 mg/L.

Level 2 Stock Solution:

Test substance, 20 times its volume of HCO20 and 10 times its volume of HCO40 were mixed then deionised water was added to obtain a nominal concentration of 40 mg/L.

Vehicle control:

8 g/L as HCO20 and 4 g/L as HCO40


Test solutions:

Level 1: 1.0 mg/L

Level 2: 0.1 mg/L


- Evidence of undissolved material (e.g. precipitate, surface film, etc): No information

Test organisms (species):

Cyprinus carpio

Details on test organisms:

TEST ORGANISM

- Common name: Common carp

- Source: Fukuoka Ken Yabekawa Fisheries Cooperative, Kukuoka, Japan

- Age at study initiation (mean and range, SD): Not stated

- Length at study initiation: Average 9.7 cm

- Weight at study initiation: Average 23.0 g

- Weight at termination: Not stated

- Lipid content: Average 4.2%

- Method of breeding: Not stated

- Health status: Healthy

- Description of housing/holding area: No details available


- Feeding during test

- Food type: Carp compounded diet (pellet form)

- Amount: 2% total fish weight

- Frequency: Twice daily except fasting the day prior to sampling


ACCLIMATION

- Acclimation period: 59 days then abnormal fish were removed. Normal fish were acclimated for a further 43 days.

- Acclimation conditions: as main test for final 12 days

- Type and amount of food: Carp compounded diet (pellet form); 2% total fish weight

- Feeding frequency: Twice daily

- Health during acclimation (any mortality observed): Not stated

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

8 wk

Total depuration duration:

0

Hardness:

132 mg/L

Test temperature:

25 ± 2°C

pH:

7.6 (dilution water)

Dissolved oxygen:

Level 1: 7.2 - 7.7. mg/L

Level 2: 7.6 - 7.9 mg/L

Control: 7.4 - 7.7 mg/L

TOC:

Not measured.

Salinity:

Not applicable

Details on test conditions:

TEST SYSTEM

- Test vessel:

- Type: open

- Material, size, headspace, fill volume: 100 L glass vessel. No other information available.

- Aeration: Not stated

- Type of flow-through: Micro-volume pump

- Renewal rate of test solution (frequency/flow rate): 1155 L/day. 2 ml/min stock solution and 800 ml/min dilution water.

- No. of organisms per vessel: 16 per vessel for test solutions; 5 per vessel for control.

- No. of vessels per concentration (replicates): 1

- No. of vessels per control / vehicle control (replicates): 1


TEST MEDIUM / WATER PARAMETERS

- Source/preparation of dilution water: Pumped ground water at Kurume Laboratory.

- Particulate matter: <1 mg/L

- Metals: Not detected for mercury, cadmium, chromate, lead, arsenic, iron and copper

- Pesticides: Not reported

- Chlorine: <0.01 mg/L

- Alkalinity: 9.5 mg/L

- Ca/mg ratio: Not stated

- Conductance: Not stated

- Intervals of water quality measurement: Every 6 months


OTHER TEST CONDITIONS

- Adjustment of pH: None

- Photoperiod: Not stated

- Light intensity: Not stated

Nominal and measured concentrations:

Nominal:

Level 1: 1.0 mg/L

Level 2: 0.1 mg/L

Measured:

Level 1: 0.865 to 0.928 mg/L

Level 2: 0.0737 to 0.0804 mg/L

Reference substance (positive control):

no

Lipid content:

4.2 %

Time point:

start of exposure

Key result

Type:

BCF

Value:

52 - 53

Basis:

whole body w.w.

Calculation basis:

other:

Remarks on result:

other: BCF calculated at 8 weeks

Remarks:

Conc.in environment / dose:1.0 mg/L

Key result

Type:

BCF

Value:

<= 188

Basis:

whole body w.w.

Calculation basis:

other:

Remarks on result:

other: BCF calculated at 8 weeks

Remarks:

Conc.in environment / dose:0.1 mg/L

Details on results:

No abnormalities were observed in the test fish.

Table 1:               Measured concentrations^a in test water

	Week 2	Week 4	Week 6	Week 8
Level 1	0.865	0.868	0.911	0.928
Level 2	0.0737	0.0784	0.0794	0.0804

a)     Average measured concentration since start of exposure period

 

Table 2: Bioconcentration factors

	Week 2	Week 4	Week 6	Week 8
Level 1	74	60	58	52
	89	91	99	53
Level 2	208	511	≤188	≤188
	189	290	≤188	≤188

 

 

Validity criteria fulfilled:

not specified

Conclusions:

BCF values of 52-53 (1 mg/l) and ≤188 (0.1 mg/l) at 8 weeks were determined in a reliable study conducted according to an appropriate test protocol, with acceptable restrictions. The restrictions were that a dispersant was used, and the concentrations of the test substance were above the predicted water solubility. In addition, the analysis was performed by AA for Si and so it was not possible to determine whether parent or degradation product was measured.
Due to the fact that a dispersant was used, and the concentrations of the test substance were above the predicted water solubility, the results at the lowest concentration are likely to be most reliable. A mean BCF value of 244 can be calculated from the values at each sampling time for the lower concentration.

Description of key information

Bioaccumulation: BCF = 244 (mean of values at each sampling point for lower test concentration) (Method equivalent to or similar to OECD 305 C, with restrictions), for a structurally-related substance, which is a reaction mass of S2, S3 and S4.

Key value for chemical safety assessment

BCF (aquatic species):

244 dimensionless

Additional information

No reliable data are available for the submission substance, which is a reaction mass of S2 and S3.

A reliable study conducted according to an appropriate test protocol, and in compliance with GLP is available for CAS 211519 -85 -6, which is a reaction mass of S2, S3 and S4, and thus is a close structural analogue of the submission substance.

BCF values of 52-53 (1 mg/l) and ≤188 (0.1 mg/l) at 8 weeks were determined. There were some restrictions in the method used. Dispersant was used, and the concentrations of the test substance were above the predicted water solubility. Therefore, the result at the lower test concentration is likely to be most reliable. A BCF of 244 (mean of values at each sampling point for lower test concentration) was determined.

This is selected as the key study.

In contact with water these reaction masses hydrolyse to the corresponding silanol hydrolysis products and ethanol. The silanol hydrolysis products and ethanol have low log K_ow values (<3), and thus have low potential for bioaccumulation.

S4 is 4,4,15,15-tetraethoxy-3,16-dioxa-8,9,10,11-tetrathia-4,15-disilaoctadecane

S3 is 4,4,14,14-tetraethoxy-3,15-dioxa-8,9,10-trithia-4,14-disilaheptadecane

S2 is 4,4,13,13-tetraethoxy-3,14-dioxa-8,9-dithia-4,13-disilahexadecane