D-Xylopyranose, oligomeric, 2-octyldodecyl xylosides

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD guideline, GLp study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Deviations:

no

GLP compliance:

yes

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

A mixed population of sewage siudge micro-organisms was obtained on 21 March 2003 from the final effluent stage of the Sevem Trent Water Pic sewage treatment plant at Loughborough, Leicestershire, UK, which treats predominantiy domestic sewage.

Duration of test (contact time):

28 d

Initial conc.:

1.5 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Preparation ofinoculum
The sample of effluent was filtered tbrough coarse filter paper (first approximate 200 ml discarded) and the filtrate maintained on continuous aeration in a temperature controlled room at 21°C prior to use.

Culture medium
The culture medium used in this study (see Appendix 2) was that recommended in the OECD Guidelines.

Preparation of the test system
The following test preparations were prepared and inoculated in 250-300 ml Biological Oxygen Demand (BOD) botties (darkened glass) with ground glass stoppers:
a) A control, in duplicate, consisting of inoculated culture medium.
b) The standard material (sodium benzoate), in duplicate, in inoculated culture medium to give a concentration of 3.0 mg/l.
c) The test material, in duplicate, in inoculated culture medium to give a concentration of 1.5 mg/l.
d) The test material (1.5 mg/l) plus the standard material (1.5 mg/1), in duplicate, in inoculated culture medium to act as a toxicity control.
Test media a-d were inoculated with sewage treatment micro-organisms at a rate of 1 drop of inoculum per litre.
The test media were transferred by siphon to BOD bottles, which were firmly stoppered to exciude all air bubbles. Sufficient bottles were prepared to allow a single oxygen determination per bottle with duplicate bottles for each test medium at each sampling occasion.
The BOD bottles were incubated in a temperature controlled water bath at 20°C.

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

ca. 36

Sampling time:

28 d

Details on results:

Points of degradation plot (test substance):
13 % degradation after 3 d
13 % degradation after 6 d
24 % degradation after 9 d
34 % degradation after 12 d
35 % degradation after 15 d
33 % degradation after 21 d
36 % degradation after 28 d

Results with reference substance:

Points of degradation plot (reference substance):
54 % degradation after 3 d
65 % degradation after 6 d
65 % degradation after 9 d
65 % degradation after 12 d
67 % degradation after 15 d
73 % degradation after 21 d
78 % degradation after 28 d

Validity criteria fulfilled:

yes

Interpretation of results:

other: not readily biodegradable

Conclusions:

The test material attained 36% degradation after 28 days and therefore cannot be considered as readily biodegradable under the strict terms and conditions ofOECD Guideline No 301D.

Executive summary:

Introduction.

A study was performed to assess the ready biodegradability of the test material in an aerobic aqueous medium. The method followed that described in the OECD Guidelines for Testing of Chemicals (1992) No 301D, “Ready Biodegradability; Closed Bottie Test” referenced as Method C.4-E of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC), and US EPA Fate, Transport, and Transformation Test Guidelines OPPTS 835.3110 Paragraph (o).

Methods.

The test material, at a concentration of 1.5 mg/l, was exposed to sewage treatment micro-organisms with culture medium in sealed culture vessels in the dark at 20°C for 28 days. The degradation of the test material was assessed by the determination of the amount of oxygen consumed. Control solutions with inoculum and the standard material, sodium benzoate, together with a toxicity control were used for validation purposes.

Results.

The test material attained 36% degradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No 301D.

Description of key information

A study was performed to assess the ready biodegradability of the test material in an aerobic aqueous medium. The method followed that described in the OECD Guidelines for Testing of Chemicals (1992) No 301D, “Ready Biodegradability; Closed Bottie Test” referenced as Method C.4-E of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC), and US EPA Fate, Transport, and Transformation Test Guidelines OPPTS 835.3110 Paragraph (o).

The test material attained 36% degradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No 301D.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable, not fulfilling specific criteria

Type of water:

freshwater