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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

poorly biodegradable

Key value for chemical safety assessment

Additional information

No experimental data on the biodegradability of 4,4'diamino-3,3',5,5'-tetramethyl-dicyclohexylmethan (TMDC; CAS 65962 -45 -0). Therefore the biodegradability was assessed by a weight of evidence including modelled data for TMDC and experimental data from a structurally similar substance (2,2'-dimethyl-4,4'-methylenebis(cyclohexylamin); DMDC; CAS 6864 -37 -5).

The biodegradability of DMDC was tested according to OECD 301C (NITE, 2001). In this study mixed inoculum according to MITI was used. After 28 days no biodegradation was observed (0% BOD/ThOD). Further studies according to OECD 302B performed by BASF (1977, 1990) support this result. DMDC is assessed to be not biodegradable even if adapted inoculum is used.

The biodegradability of TMDC was estimated using two models of CATALOGIC v5.11.9.8 and one model of EPI Suite v4.10. In all cases, the result was "not readily biodegradable."

a) CATALOGIC v5.11.9.8:

- CATALOGIC Kinetic 301F v.09.11: 6.5% after 28 d (structural domain similarity: 89.5%)

- CATALOGIC 301C v.07.08: 24% after 28 d (structural domain similarity: 89.5%)

b) EPI Suite v4.10:

- BIOWIN v4.10: Overall conclusion on ready biodegradability: not readily biodegradable

In conclusion, TMDC is assessed to be not readily biodegradable.