2-piperazin-1-ylethanol

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:

not biodegradable

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 2-piperazin-1-ylethanol(CAS 103 -76 -4) (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.

Parent compound:

The assessment of the biodegradation potential of 2 -piperazine-1-ylethanol (CAS 103-76-4) is based on the following weight-of-evidence approach:

 

Experimental data:

- Ready biodegradability in seawater: In a guideline study conducted according to OECD TG 306 Eide-Haugmo et al. (2009) tested the biodegradability the test item under saline conditions, with natural seawater as inoculum. Degradation is reported to be <10% after 28 days, based on O2 consumption.

 

Calculated data:

- CATALOGIC 301C v11.15 estimation model (OASIS Catalogic v5.13.1.156): Biodegradation of the test item is calculated to be 28% after 28 days on the basis of O2 consumption. The substance is 100% within the applicability domain of the model (BASF SE, 2020).

 

- CATALOGIC Kinetic 301B v02.09 estimation model (OASIS Catalogic v5.13.1.156): Biodegradation of the test item is calculated to be 9.7% after 28 days on the basis of O2 evolution. The substance is 100% within the applicability domain of the model (BASF SE, 2020).

 

- CATALOGIC Kinetic 301F v13.16 estimation model (OASIS Catalogic v5.13.1.156): Based on BOD, the biodegradation of the test item is calculated to be 9% after 28 days. The substance is 100% within the applicability domain of the model (BASF SE, 2020).

 

The model CATALOGIC 301C v11.15 (OASIS Catalogic v5.13.1.156) was also used to predict potential metabolites of 2-piperazin-1-ylethanol(CAS 103 -76 -4; BASF SE, 2020).

Predicted metabolites:

Metabolites (n = 20) from the degradation of  2-piperazin-1-ylethanol (CAS 103 -76 -4) 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). The metabolites with a quantity of > 0.001 mol/mol parent are regarded to be relevant for the environmental assessment. 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. Seven of the 20 metabolites have a predicted quantity of > 0.001 mol/mol parent and are regarded as relevant for further assessment. Less than half of these metabolites (3/7) are not readily biodegradable (< 60% after 28 days, based on BOD), but all of these 7 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: QSAR prediction for CAS-#103 -76 -4 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	OCCN1CCNCC1	2-piperazin-1-ylethanol (CAS 103-76-4)	0.000010	-1.47	28	not checked
1	2	O=CCN1CCNCC1	not identified	0.000010	-1.586	28	not checked
2	3	OC(=O)CN1CCNCC1	2-piperazin-1-ylacetic acid	0.006192	-3.357	22	not (pre-)registered
3	4	OC(=O)C=O	Glyoxylic acid (CAS 298-12-4)	0.007177	-1.403	100	not PBT / vPvB
4	8	C1CNCCN1	Piperazine (CAS 110-85-0)	0.975300	-0.799	1	not PBT / vPvB
5	15	OC1CNCCN1CC(O)=O	not identified	0.000000	-3.897	81	not checked
6	18	OC(C(O)=O)N1CCNCC1	not identified	0.000030	-3.585	15	not checked
7	19	OC1CN(CC(O)=O)CCN1	not identified	0.000002	-3.897	58	not checked
8	5	OC(=O)C(O)=O	not identified	0.000010	-1.736	100	not checked
9	9	OC1CNCCN1	not identified	0.000052	-2.337	75	not checked
10	16	OC(=O)CNCCNCC=O	not identified	0.000000	-4.454	81	not checked
11	20	NCCN(CC=O)CC(O)=O	not identified	0.000000	-4.709	22	not checked
12	10	NCCNCC=O	not identified	0.000000	-2.151	76	not checked
13	17	OC(=O)CNCCNCC(O)=O	not identified	0.000046	-4.788	80	not checked
14	21	NCCN(CC(O)=O)CC(O)=O	not identified	0.000898	-4.043	14	not checked
15	11	NCCNCC(O)=O	2-(2-aminoethylamino)acetic acid	0.007845	-3.922	73	not (pre-)registered
16	22	OC(=O)CN(CC=O)CC(O)=O		0.000000	-4.061	11	not checked
17	12	NCCN	1,2-Ethanediamine (CAS 107-15-3)	0.001139	-1.618	67	not PBT / vPvB
18	23	OC(=O)CN(CC(O)=O)CC(O)=O	2-[bis(carboxymethyl)amino]acetic acid	0.001473	-3.809	2	not (pre-)registered
19	13	NCC=O	2-aminoacetaldehyde	0.006952	-1.637	72	not (pre-)registered
20	24	OC(=O)CNCC(O)=O	not identified	0.000023	-3.274	81	not checked

Conclusion:

Based on a weight-of-evidence approach by the available experimental and estimated data, 2 -piperazine-1-ylethanol (CAS 103-76-4) is assessed to be not readily biodegradable according to OECD criteria.