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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

The substance is not readily biodegradable.

Key value for chemical safety assessment

Additional information

Parent compound:

The biodegradation potential of DMEE (CAS 1704-62-7) was assessed in a Zahn-Wellens test according to OECD TG 302B using activated sludge from a biological treatment plant receiving primarily industrial wastewater as inoculum. DMEE was poorly eliminated from water. The removal was determined to be 17% after 28 days based on DOC removal (BASF AG, 1987, report no. 01.82).

Further experimental data are available via read-across to the structurally similar substance 2-(2-dimethylaminoethyloxy)-N,N-dimethylethanamine (BDMAEE, CAS no. 3033-62-3) from another Zahn-Wellens test (OECD TG 302B) using activated sludge from an industrial source as inoculum. Based on a DOC removal of less than 10%, it was concluded that the substance is not inherently biodegradable (BASF AG, 1987, report no. 01.79).  

In a ready biodegradability study according to OECD TG 301F, BDMAEE was determined to be not readily biodegradable. The removal was only 2% after 28 d (CENOX/Huntsman, 1996, report no. 1928).

According to the screening criteria for persistence as listed in the REACH Guidance document Part C (v3.0, June 2017: Table C.4-1), DMEE is potentially P or vP as the substance has a low removal in the available tests on ready and inherent biodegradability (e.g. < 60% removal in OECD TG 301F and < 70% DOC removal in OECD TG 302B). The substance is to be considered as potentially P or vP according to the screening criteria for persistence as laid down in Section 3.1.1 of REACH Annex XIII.

 

Metabolites:

In addition, the model CATALOGIC 301C v11.15 (OASIS Catalogic v5.13.1) was used to predict potential metabolites of DMEE. In contrast to the experimental data, the model predicted the substance to be readily biodegradable (78% removal in 28 d, based on BOD). The substance was within the applicability domain of the model. The model predicted 19 metabolites, identifying 8 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). Two of the 8 relevant metabolites were calculated to be not readily biodegradable (between 11 and 41% after 28 days, based on BOD). The other relevant metabolites were estimated to be readily biodegradable (≥ 60% after 28 days, based on BOD). In conclusion, the majority of the predicted metabolites present in a concentration of ≥ 0.1% are estimated to be readily biodegradable.

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:

Summing up the available experimental and calculated data, DMEE (CAS 1704-62-7) is concluded to be not readily biodegradable from a precautionary point of view.