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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

Significant accumulation in organisms is not to be expected.

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.

Furthermore, according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.

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-[2-(dimethylamino)ethoxy]ethanol (DMEE) (CAS 1704-62-7) (Q)SAR results were used for aquatic bioaccumulation. 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, and for reasons of animal welfare, further experimental studies on aquatic bioaccumulation are not provided.

 

Assessment:

In accordance with column 2 of REACH Annex IX section 9.3.2 the study does not need to be conducted if the substance has a log Kow less or equal than 3. DMEE (CAS 1704-62-7) has an experimental log Kow value of -0.78 (pH 5-9, Harlan, 2012, study rep.: 41202877)

In order to assess the bioaccumulation potential of the substance, the BCF was calculated with several estimation models. Considering all models applied for the test substance, the estimated BCF values range from 0.9 to 9.42 L/kg. The substance was within the applicability domain of all estimation models except of the two VEGA submodels: Meylan v1.0.3 and CAESAR v2.1.14.

 

- BCF base-line model v03.10 (OASIS Catalogic v5.13.1): The model estimated a BCF of 9.42 L/kg without considering mitigation factors. But, water solubility and, for a minor part, metabolism and molecular size reduce the log BCF to 2.45 L/kg as estimated by the model. The test substance is within the applicability of the structural domain of the model (BASF SE, 2018).

 

- BCFBAF v3.01 (EPI Suite v4.11): Based on the estimated log Kow of -0.78 (pH 5-9, Harlan, 2012), a BCF value of 3.2 L/kg was estimated with the submodel Meylan et al. (1997/1999). This BCF estimate can be regarded as accurate as the compound was within the applicability of the model, indicating that significant bioaccumulation in organisms is not to be expected. Using the Arnot &Gobas (2003) submodel with included biotransformation rate estimates, the BCF was calculated to be 0.91 L/kg (BASF SE, 2018). The substance was not within the applicability domain of this submodel; the estimation may be less accurate due to the substance's property to appreciably ionize at physiological pH.

 

- T.E.S.T. v4.2.1 (US EPA, 2016): The model is validated using statistical external validation using separate training and test data sets. The Consensus method averages the reasonable results from all applicable methods of T.E.S.T.: hierarchical clustering, single model, group contribution, FDA, and nearest neighbor, resulting in a BCF of 1.27 (BASF SE, 2019). The confidence in the results is high and the substance is within the applicability domain of the model.

 

- VEGA v1.1.3: The KNN/Read-Across submodel v1.1.0 estimated a BCF of 1.513 L/kg (log BCF = 0.18); the substance was within the model's applicability domain.

- VEGA v1.1.3: CAESAR submodel v2.1.14 estimated a BCF of 1.175 L/kg (log BCF = 0.07); the substance was out of the applicability domain of the model

- VEGA v1.1.3: Meylan submodel v1.0.3 estimated a BCF of 3.16 L/kg (log BCF = 0.5); the substance was out of the applicability domain of the estimation model.

Assessment of relevant metabolites

The model Catalogic 301 C v11.15 (OASIS Catalogic v5.13.1) calculated 19 metabolites of DMEE, identifying 8 metabolites as relevant degradation products, with an estimated quantity of ≥ 0.1% (for details see ‘Attached background material’ of the respective Endpoint Study Record in IUCLID chapter 5.2.1). Overall, the 19 modelled degradation products of DMEE were estimated to exhibit log Kow values in a range of -5.65 to 0.35, which is ≤3. Therefore, significant accumulation in organisms is not to be expected.

An overview of the predicted metabolites is given in the table below:

Table: QSAR prediction for CAS-#1704-62-7 (DMEE) using CATALOGIC 301C v11.15 – July 2018 (OASIS CATALOGIC v5.13.1.156; 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 v11.15 – July 2018 (OASIS CATALOGIC v5.13.156); P.= parent, pred.= predicted)

#

Metab.

Smiles

Name and CAS no.

Quantity (mol/mol parent)

Log Kow

BOD

(% after 28d, pred.)

PBT-Assessment:
ECHA (disseminated substances)

P.

1

CN(C)CCOCCO

2-[2-(Dimethylamino)ethoxy]ethanol (DMEE) (CAS no. 1704-62-7)

1.00E-05

-1.21

78

not PBT/vPvB

1

2

CN(C)CCOCC=O

2-[2-(Dimethylamino)ethoxy]acetaldehyde (CAS no. 1407486-83-2)

1.00E-05

-1.23

78

not found,
not (pre-)registered

2

3

CN(C)CCOCC(O)=O

[2-(Dimethylamino)ethoxy] acetic acid (CAS no. 98278-28-5)

8.26E-02

-4.18

76

not found,
not (pre-)registered

3

11

C=O

Formaldehyde (CAS no. 50-00-0)

1.28E-05

0.35

100

not PBT/vPvB

4

4

CN(C)CC=O

2-(Dimethylamino)acetaldehyde (CAS no. 52334-92-6)

7.63E-06

-0.96

81

not found,
not (pre-)registered

5

16

OCC(O)=O

Glycollic acid (CAS no. 79-14-1)

9.02E-06

-1.07

100

not PBT/vPvB

6

17

CNCCOCC(O)=O

[2-(Methylamino)ethoxy] acetic acid (CAS no. 98137-58-7)

9.23E-03

-4.39

77

not found,
not (pre-)registered

7

19

CN(CCOCC(O)=O)CO

{2-[(Hydroxymethyl)(methyl)amino]ethoxy} acetic acid (CAS no. -)

6.25E-03

-5.65

41

not found,
not (pre-)registered

8

6

OC(=O)C=O

Glyoxylic acid (CAS no. 298-12-4)

1.71E-05

-1.40

100

not PBT/vPvB

9

12

OC=O

Formic acid (CAS no. 64-18-6)

1.28E-05

-0.46

100

not PBT/vPvB

10

5

CN(C)CC(O)=O

N,N-Dimethylglycine (CAS no. 1118-68-9)

4.85E-03

-2.73

79

not PBT/vPvB

11

18

CNCC=O

2-(Methylamino)acetaldehyde (CAS no. 145757-95-5)

8.31E-07

-1.17

83

not found,
not (pre-)registered

12

20

CN(CC=O)CO

N-(2-Hydroxyethyl)-N-methylformamide (CAS no. 1590-50-7)

5.63E-07

-2.42

20

not registered

13

7

OC(=O)C(O)=O

Oxalic acid (CAS no. 144-62-7)

1.71E-05

-1.74

100

not PBT/vPvB

14

10

CNC

Dimethylamine (CAS no. 124-40-3)

5.33E-02

-0.17

71

not PBT/vPvB

15

15

CNCC(O)=O

Sarcosine (CAS no. 107-97-1)

3.68E-02

-2.94

81

registered, but no relevant data

16

21

CN(CC(O)=O)CO

N-(Hydroxymethyl)sarcosine (CAS no. 15826-50-3)

5.02E-02

-3.20

11

not registered

17

13

CN

Methylamine (CAS no. 74-89-5)

2.82E-01

-0.64

64

not PBT/vPvB

18

22

OCNCC(O)=O

Glycine, N-(hydroxymethyl)- (CAS no. 15874-34-7)

4.89E-04

-3.41

92

not found,
not (pre-)registered

19

23

NCO

Methanol, amino- (CAS no. 3088-27-5)

5.65E-08

-2.10

100

not found,
not (pre-)registered

 

 

Conclusion:

Based on the experimental data for the log Kow and supported by a weight-of-evidence approach from calculated BCF data DMEE (CAS 1704-62-7) is concluded to not significantly accumulate in organisms.