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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

The substance is moderately biodegradable (not readily biodegradable).

Key value for chemical safety assessment

Additional information

Parent compound:


No reliable data are available for tris-2-ethylhexylamine (CAS 1860-26-0). Therefore, in order to assess the biodegradation potential of tris-2-ethylhexylamine (CAS 1860-26-0), a read across to the analogue substance di-(2-ethylhexyl)amine (CAS 106-20 -7) with structural similarity was performed. Experimental data are available from an enhanced ready biodegradability test according to OECD 301B, conducted with non-adapted, domestic activated sludge as inoculum (BASF SE, 2016). Elimination of the test item was determined to be 91% after 60 days of exposure, based on CO2 evolution. However, after 28 days, biodegradation was determined to be 69%, but the pass level of the 10-day window was slightly failed as biodegradation was approximately 58% at the end of the 10-day window.


In addition, the results from an enhanced ready biodegradability test according to OECD 301B, conducted with non-adapted, domestic activated sludge as inoculum are available (BASF SE, 2012). Elimination of the test item was determined to be 0.9% after 28 days based on CO2 evolution. Based on DOC removal, 83% of the substance was eliminated after 28 days, which is, however, interpreted to be likely due to adsorption to the sludge and/or test vessels. Additional experimental data are available from a CO2 evolution test conducted similar to OECD 301B (BASF AG, 1997; report no. 97/0028/22/1) with non-adapted, domestic activated sludge as inoculum. The substance was degraded to approximately 50% after 39 days of incubation. However, the plateau phase of the biodegradation curve was not reached after 39 days. The biodegradation curve still showed an upward trend indicating that the biodegradation of the molecule was not completed.


In addition to the read-across approach, the ready biodegradability was assessed using a QSAR model CATALOGIC Kinetic OECD 301C v.11.16. The substance was within the applicability domains of the model. The substance was predicted to be not readily biodegradable. Based on the estimated degree of degradation, moderate biodegradability is a realistic assumption.


- CATALOGIC Kinetic OECD 301C v.11.15: 7% in 28 d, not readily biodegradable


 


Metabolites:


CATALOGIC 301C v11.16 (OASIS Catalogic v5.14.1.5) predicted for the parent compound 33 metabolites, identifying 16 metabolites as relevant degradation products in terms of PBT/vPvB assessment, with an estimated quantity of ≥ 0.1% (for details see ‘Attached background material’ of the respective Endpoint Study Record).


Five of the relevant metabolites were calculated to be readily biodegradable (≥ 60% after 28 days, based on BOD). The other relevant metabolites were estimated to be not readily biodegradable (4 to 44% after 28 days, based on BOD). In conclusion, the majority of the predicted metabolites present in a concentration of ≥ 0.1% (equivalent to >=0.001 mol/mol parent) are estimated to be not readily biodegradable.


 


 


Table: QSAR prediction for CAS 1860-26-0 (Piperazine) using CATALOGIC 301C v11.16 (OASIS CATALOGIC v5.14.1.5; metabolites with a quantity > 0.001 mol/mol parent after 28 d are highlighted by grey background and bold type; metabolite no: according to (Q)SAR model Catalogic v11.16)


 




































































































































































































































































































































































#



Metabolite
(no)



Smiles



Quantity
(mol/mol parent)



LogKow



BOD prediction
(% after 28 d)



BCF including mitigating factors



PBT-Assessment
(ECHA disseminated substances)



parent



1



CCCCC(CC)CN(CC(CC)CCCC)CC(CC)CCCC



0.701



10.1



7%



6.9





1



26



CCCCC(CC)CN(CC(CC)CCCC)CC(=O)CC



0.056



7.0



4%



5.4



not listed



2



33



CCCCC(CC)CN(CC(CC)CCCC)CC(=O)CCCC



0.054



7.9



4%



5.8



not listed



3



16



CCCCC(CC)CN / 2-ethylhexylamine / CAS 104-75-6



0.041



2.7



40%



33.9



not PBT/vPvB



4



4



CCCCC(CC)C(O)=O / 2-ethylhexanoic acid / CAS 149-57-5



0.031



3.0



77%



5.5



not PBT/vPvB



5



25



CCCCC(CC)CN(CC(CC)CCCC)CC(O)(CC)CC(O)=O



0.031



3.2



14%



8.7



not listed



6



32



CCCCC(CC)CN(CC(CC)CCCC)CC(O)(CCCC)CC(O)=O



0.031



4.2



15%



20.4



not listed



7



5



CCCC=C(CC)C(O)=O / 2-ethylhex-2-enoic acid / CAS 5309-52-4



0.027



2.9



67%



13.5



not listed



8



6



CCCC(O)C(CC)C(O)=O



0.024



1.4



66%



3.2



not listed



9



8



CCCC(=O)C(CC)C(O)=O



0.020



0.9



91%



3.2



not listed



10



2



CCCCC(CC)CNCC(CC)CCCC / Bis(2-ethylhexyl)amine / CAS 106-20-7



0.015



6.6



44%



871



not PBT/vPvB



11



3



CCCCC(CC)C=O / 2-ethylhexanal / CAS 123-05-7



0.010



2.7



78%



3.8



not listed



12



27



CCCCC(CC)CN(CC(CC)CCCCO)CC(=O)CC



0.005



5.5



23%



4.8



not listed



13



28



CCCCC(CC)CN(CC(CCCC)CCO)CC(=O)CC



0.005



5.5



13%



4.8



not listed



14



35



CCCCC(CC)CN(CC(CC)CCCCO)CC(=O)CCCC



0.004



6.5



22%



5.2



not listed



15



36



CCCCC(CC)CN(CC(CCCC)CCO)CC(=O)CCCC



0.004



6.5



13%



5.2



not listed



16



34



CCCCC(CC)CN(CC(CC)CCCC)CC(=O)CCCCO



0.002



6.5



22%



5.2



not listed



17



37



CCCCC(CC)CN(CC(CC)CCCC)C(O)C(CC)CCCC



1.17E-08



8.6



47%



n.a. 



n.a. 



18



11



CC(O)CC(O)=O



0



-0.5



100%



n.a. 



n.a. 



19



12



CC(=O)CC(O)=O



0



-1.0



100%



n.a. 



n.a. 



20



10



CC=CC(O)=O



0



0.9



100%



n.a. 



n.a. 



21



9



CCCC(O)=O



0



1.1



100%



n.a. 



n.a. 



22



24



CCCCC(CC)CN(CC(CC)CCCC)CC(CC)CC(O)=O



0



4.7



16%



n.a. 



n.a. 



23



30



CCCCC(CC)CN(CC(CC)CCCC)CC(CCCC)CC=O



0



8.6



17%



n.a. 



n.a. 



24



20



CCCCC(CC)CN(CC(CC)CCCC)CC(CC)CCCC(O)=O



0



5.7



23%



n.a. 



n.a. 



25



19



CCCCC(CC)CN(CC(CC)CCCC)CC(CC)CCCC=O



0



8.6



24%



n.a. 



n.a. 



26



18



CCCCC(CC)CN(CC(CC)CCCC)CC(CC)CCCCO



0



8.7



24%



n.a. 



n.a. 



27



29



CCCCC(CC)CN(CC(CC)CCCC)CC(CCCC)CCO



0



8.7



17%



n.a. 



n.a. 



28



31



CCCCC(CC)CN(CC(CC)CCCC)CC(CCCC)CC(O)=O



0



5.7



16%



n.a. 



n.a. 



29



22



CCCCC(CC)CN(CC(CC)CCCC)CC(CC)CC(O)CC(O)=O



0



4.2



22%



n.a. 



n.a. 



30



23



CCCCC(CC)CN(CC(CC)CCCC)CC(CC)CC(=O)CC(O)=O



0



3.6



22%



n.a. 



n.a. 



31



7



CCCC(O)=C(CC)C(O)=O



0



2.0



91%



n.a. 



n.a. 



32



21



CCCCC(CC)CN(CC(CC)CCCC)CC(CC)CC=CC(O)=O



0



7.0



23%



n.a. 



n.a. 



33



13



CC(O)=O



0



0.1



100%



n.a. 



n.a. 



 


n.a.– not assessed. Metabolites with a quantity < 0.001 mol/mol parent after 28 d are not considered being relevant for the PBT/vPvB assessment and, therefore their PBT/vPvB status and BCF value were not assessed.


 


Conclusion: Based on the available experimental data from a read-across to a structurally similar substance bis(2-ethylhexyl) (CAS 106-20-7) along with the estimated data for tris-2-ethylhexylamine (1860-26-0) itself, it can be considered that the substance is moderately biodegradable (not readily biodegradable) and is not persistent.