Amides, C8-18 (even numbered) and C18 (unsaturated) alkyl, N-[3-(dimethylamino)propyl]

Biodegradation in water: screening tests

Description of key information

readily biodegradable, OECD guideline 301 F / EU method C.4-D (Manometric Respirometry Test), GLP, RL1; read-across: Amides, C8-18 even numbered, N-[3-(dimethylamino)propyl]

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

For the assessment of the biodegradability of Amides, C8-18, C18 unsatd, N-[3-(dimethylamino)propyl] a study conducted with the closely related source substance Amides, C8-18 even numbered, N-[3-(dimethylamino)propyl] is available.

Supporting data on the target substance itself is also available. The studies, however, are insufficiently documented.

A justification for read-across is given in IUCLID section 13.

The ready biodegradation of Amides, C8-18 even numbered, N-[3-(dimethylamino)propyl] was investigated in a study conducted according to OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test) and EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test) over a period of 28 days and using domestic activated sludge as inoculum. The biodegradation rate was determined by measurement of oxygen consumption. Inoculum blank, abiotic control, procedural/functional control with the reference substance sodium benzoate, and toxicity control using 100 mg/L test item and 100 mg/L reference compound were performed.

The test item proved to be readily biodegradable at a test substance concentration of 25 mg/L (81% biodegradation after 28 d). At a concentration of 100 mg/L, the test substance was biodegraded by 57% after 28 d; thus, the pass level of 60% biodegradation was not reached. However, due to the high ThOD of 2.73 mg O2/mg test substance, the test item suspension with a concentration of 25 mg/L met the criteria of 50 -100 mg ThOD or COD/L as demanded in the guideline.

No significant nitrification was observed until test end (at most 7.6% of theoretical NO3 production in the higher concentrated assay). No abiotic degradation of the test item was observed.

The reference item sodium benzoate was biodegraded by 90% after 14 days and thus fulfilling the guideline requirements.

In the toxicity control (100 mg/L test and reference substance each) the biodegradation amounted to 62% after 14 d. Thus, the test item can be considered as non toxic to the inoculum. The oxygen uptake of the inoculum blank was < 60 mg/L in 28 d and the pH was inside the range of 6.0 -8.5. The difference of extremes of replicate values of the removal of the test item at the end of the test was less than 20%.

The test item was readily biodegradable and fulfilled the 10-d window criterion.

Two supporting studies conducted with the target substance Amides, C8-18, C18 unsatd, N-[3-(dimethylamino)propyl] are also available:

In a study according to EU test method C.4-E, the test substance Amides, C8-18, C18 unsatd, N-[3-(dimethylamino)propyl] was degraded by more than 80% in 28 days. Therefore, it is considered to be readily biodegradable.

In a study according to OECD test guideline 301D, the test substance Amides, C8-18, C18 unsatd, N-[3-(dimethylamino)propyl] was degraded by 65% within 28 days. Therefore, it is considered as readily biodegradable, but failing the 10-day window.

Considering all available data, the substance is regarded to be readily biodegradable.