3-[3-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)propoxy]propane-1,2-diol

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

3 February - 30 March 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The test was performed according to OECD Guidelines and in compliance with GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Testing methods for new chemical substances (March 31, 2011, No. 0331-7, Pharmaceutical and Food Safety Bureau, Ministry of Health, Labour and Welfare; No. 120402001, Environmental Policy Bureau, Ministry of Environment, Japan).

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3-[3-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)propoxy]propane-1,2-diol

EC Number:

807-413-2

Cas Number:

70280-68-1

Molecular formula:

C13H34O5Si3

IUPAC Name:

3-[3-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)propoxy]propane-1,2-diol

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): X-22-1927
- Storage: at room temperature in the dark

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge:
On-site sludge sampling was carried out at 10 locations in Japan (samples were from surface water and surface soil of rivers, and inland sea; return sludge from sewage plants). Activated sludge, which was prepared and coltrolled in the laboratory according to the Japanese test method was used in the study. The activated sludge, which was cultivated for 18.5 hours after the synthetic sewage (glucose, peptone and potassium dihydrogenphosphate in purified water and pH adjusted to 7.0 +/- 1.0) was added, was used.
Suspended solids in activated sludge = 3850 mg/L
In the test vessel, the concentration Suspended solids (SS) was 30 mg/L.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation 1

Parameter followed for biodegradation estimation:

O2 consumption

Parameter followed for biodegradation estimation 2

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

TEST CONDITIONS
- Composition of medium: Purified water was added to each 3 mL aliquot of solutions A, B, C, and D in order to prepare 1 L of solution (Japanese Industrial Standards K 0102-2008 section 21)
- Test temperature: 25 +/- 1 ºC
- pH of medium: 7.0
- Suspended solids concentration: 30 mg/L in vessel
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration: 3
- Method used to create aerobic conditions: stirring with magnetic stirrer
- Measuring equipment: closed system oxygen consumption measuring apparatus
- Test solution preparation (test item and aniline): in each test vessel, 30 mg of the test sample was accurately weighed with an electronic analytical balance and added to the basal culture medium so that the concentration of the test item reached 100 mg/L.

SAMPLING
- Sampling frequency: BOD was measured continuously

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes (n=1)
- Abiotic sterile control: yes ( water+test substance) (n=1)
- Toxicity control: yes (n=1)

Reference substance

Reference substance:

aniline

Results and discussion

Preliminary study:

According to the preliminary test, trimethylsilanol was expected to be produced during the test and the main component was insoluble in the test solution.

% Degradation

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Remarks on result:

other: BOD

Details on results:

Analysis showed that some of the main component was converted into trimethylsilanol, 3-[3-[(dihydroxy)methylsilyl]propoxy]propane-1,2-diol and 3-[3-[(trimethylsilyl)-oxy](hydroxy)methyl]propoxy]propane-1,2-diol. The converted products and the rest of the main component were not biodegraded. The water-soluble sub-components were biodegraded and the oil-soluble sub-components were not biodegraded and remained.

BOD5 / COD results

Results with reference substance:

% degradation of anliline by oxygen consumption was 92 after 28 days.

Any other information on results incl. tables

The percentage biodegradation after 28 days was as follows:

	Replcate 1	Replicate 2	Replicate 3	Average
% biodegradation by BOD	0	1	0	0
% decrease of oil-soluble test item (by GC)	14	11	10	12
% decrease of water-soluble test item (by LC-MS)	72	72	75	73

 The % residue of the oil-soluble test item in the abiotic control (water + test substance) was 86% after 28 days.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: not readily biodegradable

Conclusions:

Under the conditions of the test, X-22-1927 was not readily biodegradable (0% biodegradation based on BOD). Chemical analysis showed that primary degradation occurred into trimethylsilanol, 3-[3-[(dihydroxy)methylsilyl]propoxy]propane-1,2-diol and 3-[3-[(trimethylsilyl)-oxy](hydroxy)methyl]propoxy]propane-1,2-diol. The converted products and the rest of the main component were not biodegraded. The water-soluble sub-components were biodegraded and the oil-soluble sub-components were not biodegraded and remained.

Executive summary:

The ready biodegradability of the test substance was investigated accoding to the OECD 301C Guideline and in compliance with GLP. Under the conditions of the test, X-22-1927 was not readily biodegradable (0% biodegradation based on BOD). Chemical analysis showed that primary degradation occurred into trimethylsilanol, 3-[3-[(dihydroxy)methylsilyl]propoxy]propane-1,2-diol and 3-[3-[(trimethylsilyl)-oxy](hydroxy)methyl]propoxy]propane-1,2-diol. The converted products and the rest of the main component were not biodegraded. The water-soluble sub-components were biodegraded and the oil-soluble sub-components were not biodegraded and remained.