Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

The diphenyl ether substane is regarded as "readily biodegradable".  The biodegradability of the test substance was determined in a BOD test (American Public Health Association, American Water Works) similar to the OECD 301D Closed Bottle Test, and in semi-continuous activated sludge (SCAS) tests.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

Based on extensive biodegradation in the BOD test (64% in 5 days, 76% biodegradation in 10 and 20 days), the test substance can be considered readily biodegradable. Extensive primary biodegradation of test substance was observed in SCAS test, with 94% degradation occuring within 24 hours at 3 mg/L. At higher concentrations (e.g. 10 and 50 mg/L, extents of biodegradation were reduced (50-60 percent). However, these tests involved a combination of diphenyl ether and biphenyl.

The biodegradation of diphenyl ether was evaluated at 100 mg/L in the MITI (I) test, which is similar to current OECD Guideline 301C. The test substance showed only a low extent of biodegradation after 14 days in the MITI (I) test. As a net positive degradation of the test substance was observed (6.3 % BOD), the test substance was shown to be not inhibitory/toxic to the inoculum at the concentration tested.