Tricyclodecanedimethanol

Biodegradation in water: screening tests

Description of key information

Octahydro-4,7-methano-1H-indenedimethanol (TCD-Alcohol DM) was assessed to be not biodegradable in an OECD TG 301B test (Laus, 2015).

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

In the key study (LAUS, 2015), the submission substance was assessed for ready biodegradability in the CO2 -evolution test according to OECD 301B (performed compliant with GLP). All validity criteria of the guideline were met.

Degradation behaviour of positive control was normal, and no inoculum toxicity was observed at a concentration of 29.0 mg/L. Abiotic degradation did not occur.

For the test item, no degradation was observed within 28 days (0% within both replicates). Therefore, the test item must be considered to be not readily biodegradable, and no indication for inherent biodegradability is given by these results. No observations were made which might cause doubts concerning the validity of the study outcome. The result of the test can be considered valid.

This is supported by a MITI (I)-Test with octahydro-4,7-methano-1H-indenedimethanol (TCD-Alcohol DM) following OECD TG 301 C. Degradation was recorded over a period of 28 days by analyzing BOD. Octahydro-4,7-methano-1H-indenedimethanol was degraded to 1 % and was assessed to be not biodegradable (NITE, 2004). The Japanese National Institue of Technology and Evaluation is considered to be a reliable source, as tests are performed according to high standards and approved test methods. Thus, the results of this study are considered to be valid and are in agreement with the resuts of the key study.

TCD-Alcohol DM may however be inherently biodegradable. In a Zahn-Wellens test (company study, Hoechst, 1979) with determination of oxygen demand relative to the test items chemical oxygen demand (COD), the inherent biodegradability of the submission substance was investigated (reliability category 3, due to insufficient documentation at that time). The test duration was 15 days, non-adapted sludge (industrial) was used as inoculum. After 15 days, 85% mineralisation were observed (based on O2 consumption relative to chemical oxygen demand). The determined chemical oxygen demand was determined correctly (2800 mg O2 / g test item vs ThOD of 2610 mg O2 / g test item based on molecular formula). After 5 and 10 days biodegradation extent was 0%. Thus, a relatively long adaption time was required.