.alpha.-Cyclodextrin, 2-hydroxypropyl ethers

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:

2002-05-15 until 2002-07-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD study under GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Cavasol W6 HP

IUPAC Name:

Cavasol W6 HP

Details on test material:

- Name of test material (as cited in study report): CAVASOL W6 HP
- Physical state: solid powder
- Impurities (identity and concentrations): as stated in substance data
- Composition of test material, percentage of components: as stated in substance data
- Lot/batch No.: 63B001
- Expiration date of the lot/batch: 2003-02-28
- Stability under test conditions: stable
- Storage condition of test material: in original container, at room temperature, in the dark

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source: domestic waste water treatment plant (Waterschaap de Maaskant, 's Hertogenbosch, The Netherlands)
- Method of cultivation: sludge was washed, the supernatant liquid phase was decanted.
- Concentration of solids: 3.8 g/l in the concentrated sludge

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

12 mg/L

Based on:

ThOD/L

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: in accordance with Guideline
- pH: 7.4 - 7.6
- pH adjusted: no
- Continuous darkness: yes
- Temperature: 22°C


TEST SYSTEM
- Culturing apparatus:2 litre all-glass brown coloured bottles
- Number of culture flasks/concentration: 2 bottles (test substance + inoculum), 2 bottles (inoculum), 1 bottle (reference compound sodium acetate + inoculum), 1 bottle (test substance + reference compound sodium acetate + inoculum)
- Test substance: test substance was directly mixed with test medium and allow to stir on a magnetic stirrer for about 6 hours in the dark; in this way the test substance reacted to the water-soluble hydrolysis product dicyclopentylsilanediol; concentration: 2.6 mg test substance/L + 0.5 ml inoculum/L test medium
- Method used to create aerobic conditions: aeration of test medium


SAMPLING
- Sampling frequency: measurement was performed on exposure days 0, 2, 5, 7, 9, 14, 19, 23, 27 and 29


CONTROL AND BLANK SYSTEM
- Inoculum blank: 0.5 ml filtered inoculum/L test medium
- Procedure control: 40 mg/l soium acetate + inoculum/ test medium
- Toxicity control: test substance + sodium acetate + inoculum

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (CO2 evolution)

Value:

1

Sampling time:

2 d

% Degradation 2

Parameter:

% degradation (CO2 evolution)

Value:

3

Sampling time:

7 d

% Degradation 3

Parameter:

% degradation (CO2 evolution)

Value:

3

Sampling time:

14 d

% Degradation 4

Parameter:

% degradation (CO2 evolution)

Value:

6

Sampling time:

23 d

% Degradation 5

Parameter:

% degradation (CO2 evolution)

Value:

11

Sampling time:

29 d

Details on results:

The reference compound sodium acetate was biodegraded by 60 % by exposure day 14 and reached an biodegradation rate of 70% by the end of the study, thus confirming suitability of the activated sludge. In the toxicity control, an average biodegradation of 35 % was noted within 14 days of exposure, thus not indicating a toxic effect of the test substance on the microorganisms.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Cavasol W6 HP is not readily biodegradable.

Executive summary:

Cavasol W6 HP was investigated for its ready biodegradability in the "Modified Sturm Test" when exposed to aerobic activated sludge from a domestic waste water treatment plant over a period of 28 days. Under the test conditions Cavasol W6 HP was found to be not readily biodegradable over the 28 -day exposure period. The reference substance sodium acetate reached the level for ready biodegradability, thus confirming suitability of the activated sludge. In the toxicity control an biodegradation of only 35% was noted within 14 days of exposure, thus not indicating a toxic effect of the test substance on the microorganisms.