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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

The Ready Biodegradability of Cyclacet was determined by the Manometric Respirometry Test according to the OECD Guidelines for Testing of Chemicals, Method No. 301 F. The concentration tested was 100 mg/l Cyclacet, with an activated sludge concentration of 30 mg/l. Cyclacet undergoes only 10 % biodegradation after 28 days in the test conditions. Thus, Cyclacet should be regarded as not readily biodegradable under the conditions in this test.  

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

In addition to the ready biodegradation of Cyclacet also the ready biodegradability of Cyclabute is presented because Cyclacet will follow a similar pathway as Cyclabute.Therefore the Cyclabute ready biodegradation test is summarised here to support the DT50 information, which is discussed in the Biodegradation Overall Endpoint summary together with the analogue justification.

Cyclabute's ready biodegradability test

The ready biodegradability of Cyclabute was determined according to OECD guideline 301F (manometric respirometry test). Cyclabute undergoes 22% biodegradation after 28 days (23% biodegradation after 60 days, 23% biodegradation after 61 days) under the test conditions. The curve obtained with the reference substance alone and with Cyclabute + reference substance shows no toxic effect of Cyclabute to the micro-organisms at the test concentration (100 mg/L). Cyclabute should be regarded as not readily biodegradable under the conditions of this test. After the 61 days the primary degradation products were determined as well as their log Kow values. No Cyclabute was found and Cyclabute's alcohol was the main metabolite (82%) and Cyclabute's ketone the minor metabolite (18%). Their log Kows were 2.4 and 3.2, respectively.