Amides, C12-18(even-numbered) and C18(unsatd.), N-hydroxyethyl

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

Study period:

Not reported

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

not specified

Remarks:

(Toxicity control)

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, non-adapted

Details on inoculum:

- Source of inoculum: Sewage treatment plant, Hochdahl
- Concentration of sludge: 1 mL/L
- Initial cell/biomass concentration: 1,000-100,000 cells/mL
- Type and size of filter used: Effluent was filtered through coarse paper filter, first 200 mL being discarded

Duration of test (contact time):

30 d

Initial conc.:

2 mg/L

Based on:

act. ingr.

Initial conc.:

5 mg/L

Based on:

act. ingr.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Solubilising agent (type and concentration if used): Emulsifier NP 9, 5EO 5PO (2 & 5 mg/L)
- Test temperature: 19.4-20.4 °C
- Aeration of dilution water: Prior to treatment, water was aerated with compressed air by means of a sintered glass tube until O2 saturation (8-9 mg O2/L) was reached


TEST SYSTEM
- Culturing apparatus:
- Number of culture flasks/concentration: 4 (inoculum blank); 2 (treatment)
- Measuring equipment: O2 levels measured by Winkler titration
- Test performed in closed vessels: Yes


SAMPLING
- Sampling frequency: 0, 5, 15 & 30 d after treatment


CONTROL AND BLANK SYSTEM
- Inoculum blank: Containing inoculated test medium
- Procedure control: Containing reference substance
- Vehicle control: Containing inoculated test medium and emulsifier (2 & 5 mg/L)

Reference substance:

other: Dodecylsulfate, 1.89 mg/L

Parameter:

% degradation (O2 consumption)

Value:

>= 56 - <= 60

Sampling time:

5 d

Parameter:

% degradation (O2 consumption)

Value:

>= 71 - <= 82

Sampling time:

15 d

Parameter:

% degradation (O2 consumption)

Value:

>= 74 - <= 82

Sampling time:

30 d

Details on results:

% degradation:
- 2 mg/L test material + 2 mg/L emulsifier: 56, 82 & 82 after 5, 15 & 30 d, respectively
- 5 mg/L test material + 5 mg/L emulsifier: 60, 71 & 74 after 5, 15 & 30 d, respectively
- 2 mg/L emulsifier: 1, 2 & 0 after 5, 15 & 30 d, respectively
- 5 mg/L emulsifier: 1, 1 & 2 after 5, 15 & 30 d, respectively

Chemical Oxygen Demand (COD) of the test substance determined by DIN-method 38409 part H41-1 was 2.23 mg O2/mg test substance.
Theoretical Oxygen Demand (THOD) of the emulsifier, based on structural formula was 2210 mg O2/g NP 10EO+5PO.

Parameter:

COD

Value:

2 230 mg O2/g test mat.

Results with reference substance:

- % degradation: 51, 77 & > 100 after 5, 15 & 30 d, respectively
- Theoretical Oxygen Demand (THOD), based on structural formula: 2.02 mg O2/mg dodecylsufate

None

Validity criteria fulfilled:

not specified

Remarks:

(Toxicity control not reported)

Interpretation of results:

readily biodegradable

Conclusions:

Under the test conditions, the test substance underwent 74-82% degradation within a 30 day period. Since the pass level (i.e., 60% ThOD) was reached, the substance can be considered as readily biodegradable.

Executive summary:

An OECD Guideline 301 D (Closed Bottle) test was conducted to determine the biodegradability of the test substance in an aerobic aqueous medium. The test (2 and 5 mg/L with 2 and 5 mg/L emulsifier, respectively) and reference (dodecylsulfate, 1.89 mg/L) substances were inoculated with the effluent of domestic sewage, kept in completely filled closed bottles and observed for degradation by measurement of the dissolved oxygen concentration over a 30 day period. Degradation of the test substance was determined to be 56-60%, 71 -82% and 74 -82% after 5, 15 and 30 days, respectively. Chemical Oxygen Demand (COD) of the test substance determined by DIN-method 38409 part H41-1 was 2.23 mg O2/mg test substance. The degradation of the reference substance was determined to be 51, 77 and >100% after 5, 15 and 30 days, respectively. The Theoretical Oxygen Demand (ThOD) of the reference substance was calculated on the basis of its structural formula to be 2.02 mg O2/mg dodecylsufate. In conclusion, the test substance underwent 74-82% degradation within a 30 day period. Since the pass level (i.e., 60% ThOD) was reached, the substance can be considered as readily biodegradable (Richterich, 2001).

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

An OECD Guideline 301 D (Closed Bottle) test was conducted to determine the biodegradability of the test substance in an aerobic aqueous medium. The test (2 and 5 mg/L with 2 and 5 mg/L emulsifier, respectively) and reference (dodecylsulfate, 1.89 mg/L) substances were inoculated with the effluent of domestic sewage, kept in completely filled closed bottles and observed for degradation by measurement of the dissolved oxygen concentration over a 30 day period. Degradation of the test substance was determined to be 56-60%, 71 -82% and 74 -82% after 5, 15 and 30 days, respectively. Chemical Oxygen Demand (COD) of the test substance determined by DIN-method 38409 part H41-1 was 2.23 mg O2/mg test substance. The degradation of the reference substance was determined to be 51, 77 and >100% after 5, 15 and 30 days, respectively. The Theoretical Oxygen Demand (ThOD) of the reference substance was calculated on the basis of its structural formula to be 2.02 mg O2/mg dodecylsufate. In conclusion, the test substance underwent 74-82% degradation within a 30 day period. Since the pass level (i.e., 60% ThOD) was reached, the substance can be considered as readily biodegradable (Richterich, 2001).