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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Four OEDC 301B studies have been performed on this substance.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable but failing 10-day window

Additional information

OECD 301B ready biodegradation studies were performed on the substance in 1994, 1996, 2000, and 2010. The 1994 study had high varibility between the two replicates and resulted in 32% and 59% degradation within 28 days, and 28% and 47% degradation at the end of the 10 day window after 10% degradation had occurred. Due to the variability between replicates the study was repeated in 1996. That study resulted in 54% and 55% degradation within 28 days and 46% degradation at the end of the 10 day window after 10% degradation had occurred. Another study was conducted in 2000 which resulted in 60% degradation within 28 days and ~50% degradation at the end of the 10 day window after 10% degradation had occurred. A 2010 study was conducted where the test substance was introduced on silica gel in an effort to improve the bioavailability of the low solubility substance. In that study 70.73 % biodegradation occured over 28 days, but the 10 day window was not achieved. With the exception of the single replicate of the 94 study, all of the studies exhibited greater than 50% degradation at 28 days and greater than 45% degradation at the end of the 10 day window after 10% degradation had occurred. It is believed that the water solubility of the susbtance may be affecting the rate of biodegradation in the OECD 301B studies which use intial concentrations of test substance that exceed or are close to the limit of solubility. While the results do not meet the criterion of 60% degradation within the 10 day window to demonstrate ready biodegradation, the degradation results indicate that the material is ulimately degradable during a short time period and would not be expected to persist in the environment.