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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

A closed bottle test comparable to OECD TG 301 D under aerobic conditions was performed with a duration of 28 d. At 0.8 mg/l of thymol 83% biodegradation was observed in 28 days and did pass the threshold of 60%. Thymol is considered to be "Readily Biodegradable" (Currenta 2010).
Also a test on inherent biodegradation comparable to OECD TG 302 B was performed with a duration of 5 days. 94.6 % of thymol was degraded during the test period (Pitter, 1976).

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Additional information

A study from MITI (1996) is also available: This study is considered as reliability 3, because the respiration inhibition on activated sludge is suspected. The test concentration (100 mg/l) used in this study was ca. 3 times higher than the 3h-EC50 of thymol (39.6 mg/l) observed on activated sludge (Bayer AG, 1986). Thymol is leagally classified according to EU 67/548/EEC annex 1; however, based on up-to-date information, new classification for aquatic environment is recommended.