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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Data from two biodegradation screening studies are available for one member of this category, 68476-55-1 (ExxonMobil Biomedical Sciences Inc., 2005 and Huntingdon Life Sciences, 2004). The results from both studies indicate only a very low level of biodegradation over 28 days. However, it is difficult to assess the persistence of UVCB streams using standard test methods as the tests measure the properties of the whole substance but do not provide information on the individual constituents. Instead, it is more appropriate to consider whether the representative components of these streams are persistent.

Representative components on these streams were identified from the compositional data. The representative components are presented in the PBT assessment section of this dossier. The biodegradation potential of these substances was compared to the PBT screening criteria for Persistence in the PBT assessment. For some constituents, experimental data is available (e.g. benzene, toluene, xylenes, styrene, DCPD) or data is reported by the registrants in their dossier. This data shows that none of the various representative components would be expected to be persistent.


The streams in this category are not considered to be readily biodegradable but their components are expected not to be persistent on the basis of the PBT assessment of representative components.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information