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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
according to guideline
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
trans-4-Methylcyclohexyl isocyanate
EC Number:
Cas Number:
Molecular formula:
C8 H13 N O
trans-4-Methylcyclohexyl isocyanate

Study design

Oxygen conditions:
Inoculum or test system:
activated sludge, domestic, non-adapted
Duration of test (contact time):
<= 28 d
Initial test substance concentration
Initial conc.:
ca. 15 mg/L
Based on:
other: mg organic carbon/L
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
Test conditions: 22°C, darkness
pH of 7.58 to 7.62 (test start) and 7.50 to 7.67 (test end)
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradation
Key result
% degradation (CO2 evolution)
ca. 5
Sampling time:
28 d
Details on results:
To be considered readily biodegradable, a test substance must achieve 60% biodegradation by the end of the test. Additionally, the test substance must biodegrade by at least 60% within 10 days of having degraded by 10%.
Trans-4-methylcyclohexylisocyanate showed limited biodegradation during the study with the maximum mean biodegradation of 5%. Trans-4-methylcyclohexylisocyanate cannot, therefore, be considered readily biodegradable.
Percent biodegradation values at each sampling interval, for the two replicates containing Trans-4-methylcyclohexylisocyanate did not vary by more than 10%, therefore satisfying the validity criterion of less than 20% difference.

Applicant's summary and conclusion

Validity criteria fulfilled:
Interpretation of results:
not readily biodegradable
Validity criteria were satisfied (degradation of reference material, CO2 production from blank controls). With the exception of the inorganic carbon content over the intended mineral media IC of the total carbon content at the beginning of the test, which has been deemed scientifically justified as having no impact upon the outcome of the study, the results are therefore considered to be valid.
Mean carbon dioxide evolution from Trans-4-methylcyclohexylisocyanate was =<5% of the theoretical carbon dioxide yield throughout the test. The level of biodegradation did not meet the requirements for ready biodegradability and Trans-4-methylcyclohexylisocyanate cannot, therefore, be classified as readily biodegradable.