Dichloromethyltetradecylsilane

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Remarks:

enhanced ready biodegradability test (60 d)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

30 Jan - 31 Mar. 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

1992

Deviations:

yes

Remarks:

60 d duration

GLP compliance:

yes (incl. QA statement)

Remarks:

Staatliches Gewerbeaufsichtsamt Hildesheim, Germany

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: municipal sewage treatment plant, 31137 Hildesheim, Germany
- Laboratory culture: no
- Storage conditions: aerobic conditions by aeration with CO2-free air
- Storage length: 7 d
- Pretreatment: activated sludge was washed twice with chlorine free tap water. After the second washing the settled sludge was resuspended in mineral salts medium and was maintained in an aerobic condition by aeration for 2 h. Thereafter the sludge was homogenized with a blender. After sedimentation the supernatant was decanted and maintained in an aerobic condition by aeration with CO2-free air for 7 d.
- Concentration of sludge: 10 mL sludge/L were used to initiate inoculation
- Initial cell/biomass concentration: 1.47 x 10^9 CFU/L corresponding to approx. 1.47 x 10^7 CFU/L in the final test solution
- Water filtered: no

Duration of test (contact time):

60 d

Initial conc.:

20 mg/L

Based on:

test mat.

Initial conc.:

52.4 mg/L

Based on:

ThOD

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: mineral salts medium according to OECD 301 F
- Solubilising agent (type and concentration if used): Silicone Oil (WACKER® AR 20 SALBEN SILICONÖL) - for more information see field "any other information on material and methods incl. tables"
- Test temperature: 21.8 – 22.1 °C
- pH: 7.60 - 7.92
- Continuous darkness: yes
- Other: continuous stirring

TEST SYSTEM
- Test vessels: brown glass bottles (volume 500 mL)
- Test volume: 250 mL
- Number of culture flasks/concentration: 2
- Measuring equipment: OxiTop® measuring heads, WTW

SAMPLING
- Sampling method and frequency: oxygen consumption was determined in the incubation vessels by the OxiTop® measuring system at 360 measuring points during the 60 d incubation period

CONTROL AND BLANK SYSTEM
- Inoculum control: 2
- Inoculum control with silicon oil: 2 (500 µL Silicone oil was pipetted directly into the inoculated test medium)
- Toxicity control: 1
- Functional control: 1

STATISTICAL METHODS: Excel, MICROSOFT CORPORATION, SigmaPlot, SPSS CORPORATION

Reference substance:

benzoic acid, sodium salt

Remarks:

45 mg/L

Parameter:

% degradation (O2 consumption)

Value:

41

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

39

Sampling time:

60 d

Details on results:

In the toxicity control containing both test and reference item 59% degradation occurred within 15 days. After 28 days the biodegradation was 65% and after 60 days it came to 66%. The degradation of the reference item was not inhibited by the test item.

Results with reference substance:

The pass level for ready biodegradation (= 60% degradation) was reached within 4 d. The adaptation phase changed to degradation phase within 2 days (degradation > 10%) and the biodegradation came to a maximum of 98% on day 60.

VALIDITY CRITERIA:

Table 1: Validity criteria

Criterion from the guideline	Outcome	Validity criterion fulfilled
Difference of extremes of replicate values of the removal of the test chemical at the plateau, at the end of the test or at the end of the 10-d window, as appropriate, is less than 20%.	1% difference on day 28 and 8% on day 60	yes
Percentage degradation of the reference compound has reached the pass levels by day 14.	72% after 4 d	yes
The oxygen uptake of the inoculum blank is normally 20-30 mg O2/L and should not be greater than 60 mg/L in 28 days.	mean oxygen depletion in the inoculum control was 13.7 mg O2/L on day 28 and 19.1 mg O2/L on day 60   mean oxygen depletion in the inoculum control with silicone oil was 13.0 mg O2/L on day 28 and on day 60 16.9 mg O2/L	yes

RESULTS:

Table 2: % Biodegradation of test item in comparison to the functional control and the toxicity control.

[d]	Biodegradation [%]
	Functional Control	Test Item		Toxicity Control
	R1	P1	P2	T1
2	27	1	0	16
4	72	0	0	38
7	81	6	3	46
9	85	18	11	52
11	88	25	22	57
13	89	28	26	58
15	90	30	30	59
17	92	31	34	61
19	92	35	36	62
22	94	37	37	63
24	95	40	38	64
26	94	41	39	64
28	94	41	40	65
30	95	42	40	65
32	95	40	38	65
34	95	41	38	66
37	95	43	40	66
39	95	42	39	66
41	95	44	39	66
43	95	43	38	66
45	95	44	38	67
47	95	43	38	66
49	96	44	38	67
52	96	45	37	67
54	96	44	36	66
56	97	43	36	66
58	97	44	36	67
60	98	43	35	66

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.

Interpretation of results:

not readily biodegradable

Conclusions:

The tested substance is not readily biodegradable (41% biodegradation) within 28 days and not inherently biodegradable (39% biodegradation) within 60 days.

Reference 2

Endpoint:

biodegradation in water: screening test, other

Remarks:

enhanced ready biodegradability test (60 d)

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Please refer to the attached justification below and the overall justification for grouping of substances attached in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Parameter:

% degradation (O2 consumption)

Value:

41

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

39

Sampling time:

60 d

Conclusions:

The target substance is regarded as not readily biodegradable (41%, 28 days) and not inherently biodegradable (39% biodegradation, 60 days) based on an extended OECD 301F test on the read across substance chloro(dodecyl)dimethylsilane (CAS 66604 -31 -7). 

Description of key information

Dichloromethyltetradecylsilane (CAS 59086-80-5) is regarded as not readily biodegradable (41%, 28 days) and not inherently biodegradable (39% biodegradation, 60 days) based on an extended OECD 301F test on the read across substance chloro(dodecyl)dimethylsilane (CAS 66604 -31 -7). 

Additional information

There are no data on biodegradation for dichloromethyltetradecylsilane (CAS 59086-80-5). In accordance with Regulation (EC) No. 1907/2006 Annex XI, 1.5 “Grouping of substances and read across” and in accordance with the read across assessment framework (RAAF, ECHA 2017) a read across from the analogue substance chloro(dodecyl)dimethylsilane (CAS 66604-31-7) has been applied to support the environmental hazard assessment of the substance. Details on the read across justification can be found in the attached justification in the respective target entry and in the overall justification for grouping of substances attached in IUCLID Section 13.

 

The available study (2017) investigating the biodegradation of the analogue substance chloro(dodecyl)dimethylsilane (CAS 66604-31-7) was conducted according to OECD guidance 301F and GLP standards. The inoculum (non-adapted activated sludge from a sewage treatment plant) was exposed for 60 days to 20 mg/L test substance and biodegradation was calculated based on O2 consumption. The substance reached a biodegradation value of 41% after 28 d and 39% after 60 d. Therefore, the read across substance is considered as not readily and not inherently biodegradable within 28 d / 60 days.

 

Based on the results of the analogue substance, dichloromethyltetradecylsilane (CAS 59086-80-5) is considered as not readily biodegradable and not inherently biodegradable.