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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Not ready biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

Betamethasone is not ready biodegradable. In the QSAR study carried out with BIOWIN v.4.10 (as part of the EPISUITE v.4.0, 2008) almost all results, but one, clearly showed the characteristic of not ready biodegradable substance. The prediction obtained satisfies all the conditions required to consider the result as reliable.

As read-across study, the ready biodegradability of Prednisolone (CAS 50 -24 -8), determined with the Closed Bottle Test according to the OECD guideline 301 D, was reported. Prednisolone was tested at a nominal concentration of 2 mg/L.

The following biodegradation was determined at the end of the 28 -d period:

- Prednisolone 2 mg/L:       38.2%

- Na benzoate 2 mg/L:       70.5%

- Toxicity control:              41.6%

The test item is considered as not readily biodegradable. (Eurofins S10 -03600)