6,6'-di-tert-butyl-4,4'-thiodi-m-cresol

Biodegradation in water: screening tests

Description of key information

The key result for biodegradation was derived via a weight of evidence approach and indicates no biodegradation in water under the given test conditions.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Biodegradation of 4,4'-sulfanediylbis(2-tert-butyl-5-methylphenol) was investigated in three studies, of which only one was found reliable. The test conditions and the documentation of one study (Gledhill, 1980) were inadequate to investigate the anaerobic biodegradability potential of the test compound. Under the given test conditions, it had to be concluded that no biodegradation occurred. Although this report suggested that the results were due to poor quality of the inoculums, the results of the reliable study (Monsanto, ES-80-SS-42) also showed that the rate of mineralization can be expected to be relatively slow and that extensive ultimate biodegradation in the environment is unlikely to occur. The third study (Monsanto, ES-78-SS-28) also indicated that 4,4'-sulfanediylbis(2-tert-butyl-5-methylphenol) is significantly resistant to primary degradation. In addition, results from the predictive models in BIOWIN indicate degradation can be assumed to happen very slowly. Therefore, 4,4'-sulfanediylbis(2-tert-butyl-5-methylphenol) should be considered not readily nor inherently biodegradable and further testing is not required.