N,N'-[(methylimino)bis(trimethylene)]bis(stearamide)

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

GLP compliance:

no

Remarks:

However, the test system is accredited by DAkkS. DAkkS (Deutsche Akkreditierungsstelle) is the national accreditation body of the Federal Republic of Germany.

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Sludge from the municipal treatment plant Tübingen
- Preparation of inoculum for exposure: the activated sludge was washed with medium for three times.
After the third washing the sludge was homogenized with Ultra-Turrax and adjusted to a dry content of 1.5 g/L with medium.
The activated sludge was maintained under aerobic conditions by aeration and stirring until use.
- Pretreatment: no pretreatment
- Concentration of sludge: 1.5 g/L dry matter; 5 mL of the activated sludge was used as inoculum resulting in 30 mg/L dry matter in the test vessels

Duration of test (contact time):

ca. 28 d

Initial conc.:

ca. 100 mg/L

Based on:

COD

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: mineral salt medium according to OECD guideline 301F
- Solubilising agent (type and concentration if used): an emollient was used
- Test temperature: 20 °C
- pH adjusted: 7.6
- Suspended solids concentration:
- Continuous darkness: yes
- Other: Allylthioure (Allylthioharnstoff, ATH) a nitrification inhibitor was used in two samples to allow for oxygen consumption for nitrification.

TEST SYSTEM
- Culturing apparatus: 500 mL brown glass bottles
- Number of culture flasks/concentration: 2 replicates
- Method used to create aerobic conditions: stirring
- Measuring equipment: OxiTop for oxygen measurements

Reference substance:

ethylene glycol

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 83

Sampling time:

28 d

Key result

Parameter:

COD

Value:

ca. 296 mg O2/g test mat.

Interpretation of results:

readily biodegradable

Conclusions:

In a study conducted according to OECD guideline 301F the test substance N,N'-[(methylimino)bis(trimethylene)]bis(stearamide) was considered to be readily biodegradable.
Biodegradation after 28 days was 83 %, fulfilling the 10 day window.

Description of key information

In a study conducted according to OECD guideline 301F the test substance N,N'-[(methylimino)bis(trimethylene)]bis(stearamide) was considered to be readily biodegradable.

Biodegradation after 28 days was 83 %, fulfilling the 10 day window.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater