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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

A structurally related analogue was found to be non biodegradable in a biodegradation test according to OECD Guideline 302C (Caspers et al, 1986). There was 0% biodegradation found after 28 days.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

The test substance is covered by the category approach of methylenediphenyl diisocyanates (MDI). Hence, data of the category substances can be used to cover this endpoint. The read-across category justification document is attached in IUCLID section 13. It is important to note that the MDI category approach for read-across of environmental and human hazards between the MDI substances belonging to the MDI category is work in progress under REACH. Therefore the read-across document should be considered a draft.

A biodegradation screening test in water is available for the structurally related analogue PMDI. According to OECD Guideline 302C (Inherent biodegradability: Modified MITI Test (II)) 0% biodegradation was found after 28 days based on oxygen consumption under aerobic condtions with domestic sewage (adaptation not specified).

MDI hydrolyses very rapidly in water. Hence, this test measured the biodegradation of the hydrolysis products of PMDI. Based on the justification in the category approach, it is assumed that all MDI analogues included in the category are not readily biodegradable.