Butyric anhydride

Biodegradation in water: screening tests

Description of key information

Butyric acid has been demonstrated to be readily biodegradable in a valid degradation test according to OECD TG 301 E (Hüls, 1996).

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

The biodegradability of butyric acid was tested in seven studies. In two of them anaerobic conditions were applied.

  

study record	Method	Conditions	Reliability	Result
Hüls, 1996	other guideline: EC directive 84/449/EEC C.3; similar to OECD TG 301 E	aerobic (14 days)	1 KS	81% within 5 days 100% at14 days readily biodegradable
Hoechst AG, 1979	Zahn-Wellens test; similar to OECD TG 302 B	aerobic (5 days)	2	>95% degradation
Urano 1986	MITI (I) method; similar to OECD TG 301 C	aerobic (250 hrs)	2	58 to 82% ThOD within 6 days; < 90% at day 10 readily biodegradable
Dias 1971	Standard methods for the examination of water and wastewater, 1965, biochemical oxygen demand test	aerobic (30 days)	2	48% and 58% at day 10 and 30; ready biodegradability not met
Lutin, 1979	similar to OECD Guideline 301 F	aerobic (72 hrs)	3	ca. 43% at 72 hrs
Chou, 1978	anaerobic degradation by acetate adapted domestic activated sludge (methanogenic culture, repeated additions of substrate))	anaerobic	3 (not suited for ready biodegradability	after a 3 day lag period, complete anaerobic degradation of butyric acid with a degradation rate of 284 mg/(L*d)
Kameya, 1995	anaerobic biodegradation test using methanogenic bacteria as inoculum	anaerobic	3 (not suited for ready biodegradability	complete anaerobic degradation of butyric acid within 7 days

 

 

The ready biodegradability of butyric acid was tested in a valid Modified OECD Screening Test according to EU Directive 84/449/EEC C.3 (similar to OECD TG 301 E; RL1). After 5 days, the test substance was degraded to 81% and after 14 days to 100% (Hüls, 1996). In several other biological degradation tests, butyric acid was demonstrated to undergo biodegradation up to 95%.

 

In one study (Dias, 1971), degradation only reached 58% within 30 days (parameter examined: oxygen consumption). This study is estimated not adequately to represent the genuine biodegradation potential of butyric acid. But reasons for the differing results are not obvious.

 

Based on the results of the key study (Hüls, 1996) and supported by the results of other studies (Urano, 1986; Hoechst AG, 1979), butyric acid is readily biodegradable.

 

In addition, butyric acid was demonstrated to undergo complete biodegradation under anaerobic conditions as well.