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Environmental fate & pathways

Endpoint summary

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Three studies on ready biodegradation are available for the PFAE fumarates category (i.e. Didodecyl fumarate CAS 2402-58-6, MW 453 g/mol, Ditetradecyl fumarate CAS 10341-03-4, MW 509 g/mol and 2-Butenedioic acid (E)-, di-C18-22-alkyl esters CAS 68921-53-9, MW 621-733 g/mol). In all tests the pass level for ready biodegradation was reached in 28 days. The strict criterion of the 10-day window however was not fulfilled for Didodecyl fumarate CAS 2402-58-6 and Ditetradecyl fumarate CAS 10341-03-4 (both monoconstituent substances). These substances are therefore regarded as readily biodegradable, but failing 10-day window. For 2-Butenedioic acid (E)-, di-C18-22-alkyl esters CAS 68921-53-9 the 10-day window is however not applicable, since this substance is a UVCB. This substance is therefore regarded as ready biodegradable. Based on a weight of evidence approach the remaining three members of the category (namely: 2-Butenedioic acid (E)-, di-C8-18-alkyl esters CAS 68610-90-2, MW 341-621 g/mol, 2-Butenedioic acid (E)-, di-C12-18-alkyl esters CAS 68921-51-7, MW 453-621 g/mol and 2-Butenedioic acid (E)-, di-C16-18-alkyl esters CAS 68921-52-8, MW 565-621 g/mol) were assessed regarding their biodegradability using the studies mentioned above. As the pass level was reached in all tests and due to the variable composition of the remaining category members, these substances were assessed as readily biodegradable.

For two substances, namely Ditetradecyl fumarate (CAS 10341-03-4) and 2-Butenedioic acid (E)-, di-C18-22-alkyl esters (CAS 68921-53-9) OECD 301B tests were enhanced up to 60 days, resulting in high overall degradation rates for both (87- 90 % after 60 d).

CAS

Substance name

% degradation after 28 days

% degradation after 60 days

Biodegradation asssessment

2402-58-6

Didodecyl fumarate

67 % (BODIS test)

--

readily, but failing 10 day window

10341-03-4

Ditetradecyl fumarate

71 % (OECD 301B)

90 % (OECD 301B)

readily, but failing 10 day window

68610-90-2

2-Butenedioic acid (E)-, di-C8-18-alkyl esters

RA: CAS 2402-58-6

RA: CAS 10341-03-4

RA CAS 68921-53-9

--

readily biodegradable

68921-51-7

2-Butenedioic acid (E)-, di-C12-18-alkyl esters

RA: CAS 2402-58-6

RA: CAS 10341-03-4

RA CAS 68921-53-9

--

readily biodegradable

68921-52-8

2-Butenedioic acid (E)-, di-C16-18-alkyl esters

RA: CAS 2402-58-6

RA: CAS 10341-03-4

RA CAS 68921-53-9

--

readily biodegradable

68921-53-9

2-Butenedioic acid (E)-, di-C18-22-alkyl esters

62 % (OECD 301B)

87 % (OECD 301B)

readily biodegradable

The available studies cover the outer borders of this category so that this endpoint is covered by interpolation (i.e. studies are available for the lower alcohol chain length (C12, C14) and highest alcohol chain length (C18/C22), respectively). Only two constituents, i.e. C8 and C10 fatty acid ester components of 2-Butenedioic acid (E)-, di-C8-18-alkyl esters (CAS 68610-90-2) are outside of the category. However, since the C-chain length is a determining factor in biodegradation, the biodegradability for these two components is even expected to be faster compared to higher chain lengths fumarates. 2-Butenedioic acid (E)-, di-C18-22-alkyl esters (CAS 68921-53-9) represents the higher end of the category consisting of the longest fatty alcohol chain lengths and therefore represents a worst case for biodegradation since as mentioned above, the C-chain length of the fatty alcohol is the determining factor for biodegradation. Thus, the assumption that all members of the PFAE fumarates category are either readily biodegradable (in case of UVCBs) or readily biodegradable, but failing 10-day window (in case of monoconstituent substances) is clearly underlined by the result for this substance (readily biodegradable). The substances are thus expected to be rapidly degraded by microorganisms in both the aquatic and terrestrial environment, therefore in accordance with Regulation (EC) No. 1907/2006, 9.2.1.2 – 9.2.1.4, further simulation testing for water and sediment or soil biodegradation are not necessary.