Fatty acids, C8-18 and C18-unsatd., reaction products with diethanolamine and propylene oxide

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: GLP guideline study

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Municipal activated sludge from a wastewater treatment plant.
- Preparation of inoculum for exposure: a aliquot of activated sludge suspension was sieved (mesh size = 1mm). After settling the supernatant was discarded and sludge was filled up with water.
- Concentration of sludge: 6 g/L

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

other: TOC

Initial conc.:

30 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: 1500 ml test solution contained ca. 30 mg/L test substance (44.8 mg/vessel, 20 mg/L TOC), 19.5 ml mineral medium, 7.5 ml inoculum
- Test temperature: 22 ± 2 °C
- pH:
- study initation: 7.4
- study end: 7.2 - 7.3

TEST SYSTEM
- Culturing apparatus: 2 L incubation bottles, filled up to a volume of 1.5 L
- Number of culture flasks/concentration: 3
- Method used to create aerobic conditions: aeration performed with CO2 free air at a flow of approx. 800 ml per hour
- Details of trap for CO2 and volatile organics if used: Bottles were connected to two serial scrubbing bottles (total volume 250 ml) filled with 100 ml 0.05 sodium hydroxide solution.

SAMPLING
- Sampling frequency: twice a week

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2
- Inhibition control: 1
- Reference substance: 1

Reference substance:

aniline

Key result

Parameter:

% degradation (CO2 evolution)

Value:

60 - 70

Sampling time:

28 d

Details on results:

- 10-day window was failed

- Duration of the adaption phase: 2 d
- Degradation degree of the inhibition control after 14 days: 67%

Results with reference substance:

- Degradation degree of the reference substance after 14 days: 71%

Since Kerocom FM 38 is a mixture, the application of the 10-day window criterion is not scientifically justified.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Description of key information

Readily biodegradable: >60% CO2 evolution in 28 days (OECD 301B)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

In a CO2 evolution test according to OECD guideline 301 B the biodegradation of the test substance was investigated (BASF SE, 2009). After 28 days > 60 % degradation was determined. The degradation degree was not reached within the 10 - day window; however, the application of the 10-day window criterion is not scientifically justified for UVCB substances since sequential degradation can be assumed. Exceeding the pass level (60 % Degradation based on CO2 evolution) within the standard test duration of 28 days is considered to be sufficient to evaluate the described UVCB substance as readily biodegradable.