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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

not readily biodegradable, but moderately eliminated from water

Key value for chemical safety assessment

Additional information

QSAR-disclaimer 

In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met.

 

According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.

 

For the assessment of the substance (Q)SAR results were used for aerobic biodegradability in water.The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.

 

Therefore, further experimental studies on aerobic biodegradability in water are not provided.

Assessment

No experimental data are available on the ready biodegradability of 1,1'-(methylimino)dipropanol (CAS 4402 -30 -6). Therefore, the biodegradability of was assessed based on a weight of evidence approach using data from an inherent biodegradability test and QSAR models for the substance itself. In addition, experimental data from the structurally similar substance 1,1',1''-nitrilotripropan-2-ol (CAS 122-30-2) were used to support the assessment.

In an inherent biodegradability test according to OECD guideline 302B (Inherent biodegradability: Zahn Wellens/ EMPA Test) using activated sludge from a wwtp treating predominantly industrial wastewater, the removal degree of 1,1'-(methylimino)dipropan-2 -ol was 37% after 30 days (BASF AG 1987; test no. 01.78).

The biodegradability was estimated using four models. It was checked if the substance was within the applicability domain (AD) of the models. In most cases, the result was "not readily biodegradable."

CATALOGIC v5.12.1:

- CATALOGIC Kinetic 301B v02.09: 0% after 28 d (not in AD; AD: 100% parametric, 90% structural; 100% metabolic)

- CATALOGIC 301C v10.14: 16% after 28 d (in AD; AD: 100% parametric; 100% structural; 100% metabolic)

- CATALOGIC Kinetic 301F v13.16: 5% after 28 d (not in AD; AD: 100% parametric; 90% structural; 100% metabolic)

EPI Suite v4.11:

- BIOWIN v4.10: Overall conclusion on ready biodegradability: readily biodegradable (in AD)

The data from the structurally similar substance 1,1',1''-nitrilopropan-2 -ol (CAS 122 -30 -3) also support the poor biodegradability. In a ready biodegradability test, no biodegradability was observed under the test conditions (OECD 301F; 0% after 28 d; DOW, 1998). In an inherent biodegradability test using activated sludge from a wwtp treating inudstrial sewage, the DOC removal was below 10% (BASF AG, 1981).

Based on the available data, the substance is assessed to be not readily biodegradable. The substance is moderately eliminated from water.