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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)

Key value for chemical safety assessment

Biodegradation in water:
inherently biodegradable

Additional information

Several studies on biodegradation in water, BOD5 and COD are available for Direct Orange 39 (CAS 1325 -54 -8) and for the substance with CAS Nr. 1195028 -55 -7 (which has the identical chemical molecular structure in respect to the anionic organic components.). The biodegradation in water study considered as a Key Study is the one done according to OECD guideline 301E on the substance CAS 1195028 -55 -7. The result on % of degradation based on the DOC removal parameter shows that the substance can not be classified as ready biodegradable, but it has an inherent biodegradability as it presents a DOC removal of 48% after 28 days. Biodegradability refers to the organic part of the substance, and both the substance and CAS 1195028 -55 -7 and CAS 1325 -54 -8 have the same organic molecular structure. Therefore, it can be concluded that both substances have the same or very similar biodegradability behavior. For that reason, it is justified to consider the substance Direct Orange 39 as inherently biodegradable.