Reaction product of 2,4-Dinitrotoluene and 2,6-Dinitrotoluene and hydrogen

Biodegradation in water: screening tests

Description of key information

Not readily biodegradable (according to OECD criteria).

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Parent compound:

The ready biodegradability of the reaction product of 2,4-Dinitrotoluene and 2,6-Dinitrotoluene and hydrogen was tested in two studies:

- In a modified MITI (I) test according to OECD 301C under GLP (BASF SE, 2011; Project No. 09G0117/10G061), after an exposure of 28 days the degree of biodegradation of the test substance was -1% based on BOD/ThOD measurement. The removal of DOC was -3.9%.

- in an enhanced CO2 evolution test according to OECD 301B under GLP (BASF SE, 2020, report no.: 22G0117/10G146), after an exposure of 56 days, the degree of biodegradation of the test substance was 12% based on CO2/ThCO2 measurement. The removal of DOC was 8%.

Based on the outcome of both studies, the substance is considered to be not readily biodegradable (according to OECD criteria).

 

The model CATALOGIC 301C v11.15 (OASIS Catalogic v5.13.1.156) was used to predict potential metabolites of the representative constituents of the reaction product of 2,4-Dinitrotoluene and 2,6-Dinitrotoluene, CAS 13897 -55 -7 and CAS 13897 -56 -8. Both constituents were within the applicability domain of the model (100%).

 

Predicted metabolites from Catalogic 301C v11.15 (OASIS Catalogic v5.13.1.156):

Metabolites (n = 86) from the degradation of 4-methylcyclohexane-1,3-diamine (CAS 13897-55-7) and 47 metabolites from the degradation of 2-methylcyclohexane-1,3-diamine (CAS 13897-56-8) were predicted using the QSAR model Catalogic 301C v11.15. The metabolites are identified by their SMILES code. The table below also lists the estimated quantity of appearance from the degradation as well as the log Kow and the biodegradability (BOD prediction). In the table below only those metabolites with a quantity of > 0.001 mol/mol parent (approx. 0.1%) are listed, as they are regarded to be relevant for the environmental assessment (for further details see corresponding study entries, IUCLID Ch. 5.2.1). It was attempted to identify the relevant metabolites either via the QSAR Toolbox and/or the advanced search option for substances on the ECHA website. In case a name and/or CAS number was assigned, the PBT/vPvB status according to the ECHA website was checked.

Based on the available information, it can be concluded that all metabolites have a log Kow < 3. Nine of the 86 metabolites of 4-methylcyclohexane-1,3-diamine (CAS 13897-55-7) and 10 of the 47 metabolites of 2-methylcyclohexane-1,3-diamine (CAS 13897-56-8) have a predicted quantity of > 0.001 mol/mol parent (approx. > 0.1%) and are regarded as relevant for further assessment. Half of these metabolites (9/19) are not readily biodegradable (< 60% after 28 days, based on BOD), but all of these 19 metabolites have a log Kow < 3; therefore, a significant bioaccumulation potential is not expected. It can be concluded that these substances are not PBT/vPvB substances.

Their toxicity (T) was not further assessed as no critical combination of potential P/vP (= not readily biodegradable) and potential B/vB (log Kow > 3) properties was observed.

 

Table 2: QSAR prediction for CAS-#13897-55-7 and CAS-#13897-56-8 using CATALOGIC 301C v11.15 – July 2018 (OASIS CATALOGIC v5.13.1.156; metabolites with a quantity > 0.001 mol/mol parent (approx. 0.1%) after 28 d are highlighted by grey background and bold type; metabolite no: according to (Q)SAR model Catalogic v11.15 – July 2018 (OASIS CATALOGIC v5.13.1.156))

#	Metabolite No	Smiles	Substance name (CAS)	Quantity (mol/mol parent)	LogKow	BOD prediction (% after 28 d)	PBT-Assessment (ECHA (disseminated substances)
parent	1	CC1CCC(N)CC1N	4-methylcyclohexane-1,3-diamine (CAS 13897-55-7)	0.132	0.12	55	Not PBT/vPvB
1	2	CC1CCC(N)CC1=O	3-amino-6-methylcyclohexanone	0.155	-0.001	63	No results were found.
2	15	CC1CCC(=O)CC1N	3-amino-4-methylcyclohexanon (CAS 2138125-40-1)	0.155	-0.001	62	No results were found.
7	63	CC1CCC(N)C(=O)OC1N	3,7-diamino-6-methyl-oxepan-2-one	0.0011	-0.2457	63	No results were found.
8	75	CC1CCC(N)OC(=O)C1N	3,7-diamino-4-methyl-oxepan-2-one	0.0011	-0.2457	58	No results were found.
20	18	NC1CCC(C(O)=O)C(N)C1	2,4-diaminocyclohexancarboxylic acid	0.0034	-3.933	55	No results were found.
29	19	NC1CCC(C(O)=O)C(=O)C1	4-amino-2-oxocyclohexane-1-carboxylic acid	0.0014	-4.438	72	No results were found.
30	27	NC1CC(=O)CCC1C(O)=O	6-amino-4-oxocyclohexane-1-carboxylic acid	0.0039	-4.438	56	No results were found.
71	24	NC(CC(O)=O)CC(O)=O	3-aminopentanedioic acid (CAS 1948-48-7)	0.003418	-5.008	62	No results were found.
80	73	CCC(O)=O	propionic acid (CAS 79-09-4)	0.001625	0.578	100	Not PBT/vPvB
parent	1	CC1C(N)CCCC1N	2-methylcyclohexane-1,3-diamine (CAS 13897-56-8)	0.13	0.12	50	Not PBT/vPvB
1	2	CC1C(N)CCCC1=O	5-amino-6-methylcyclohexanone	0.31	0.00	57	No results were found.
13	16	NC1CCCC(N)C1C(O)=O	2,6-diaminociclohexane-1-carboxylic acid	0.0035	-3.93	36	No results were found.
20	17	NC1CCCC(=O)C1C(O)=O	6-amino-2-oxocyclohexane-1-carboxylic acid	0.0079	-4.44	39	No results were found.
27	50	C=C	Ethylene (CAS 74-85-1)	0.0010	1.27	10	Not PBT/vPvB
29	18	OC(=O)C1C(=O)CCCC1=O	2,6-dioxocyclohexane-1-carboxylic acid	0.0042	-0.39	60	No results were found.
37	29	CC(C=O)C(N)CC(O)=O	3-amino-4-formyl-pentanoic acid	0.0016	-4.26	47	No results were found.
40	8	CCC(=O)OCCC(O)=O	3-(propionyloxy)propane acid (CAS 1085694-20-7)	0.058	0.61	92	No results were found.
43	40	CCC(N)=CC	pent-1-en-3-amine (CAS 70267-50-4)	0.0014	1.17	17	No results were found.
46	21	OCC(=O)CCCC(O)=O	6-hydroxy-5-oxohexanoic acid (CAS 497844-76-5)	0.0040	-0.55	100	No results were found.
47	23	OCCCC(=O)CC(O)=O	3-oxo-6-hydroxyhexanoic acid	0.0040	-1.46	94	No results were found.