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Classification & Labelling & PBT assessment

PBT assessment

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PBT assessment: overall result

PBT status:
the substance is not PBT / vPvB
Justification:

Persistence Assessment

Methylcyclohexane is not readily biodegradable in the aquatic environment. However, as it rapidly evaporates into the atmosphere; the degradation in air is considered as more important and relevant degradation pathway. Considering the combination of aquatic biodegradation testing (OECD 301D: 0% in 28 days based on oxygen consumption) and photodegradation (t1/2 = 37.9 h for indirect photodegradation), Methylcyclohexane is regarded as P but not vP.

Bioaccumulation Assessment

The screening criterion for Bioaccumulation (B) stipulated in the ‘Guidance on information requirements and chemical safety assessment – Chapter R.11: PBT Assessment’ (ECHA, 2012) is a Log Kow > 4. Since the log Kow for methylcyclohexane is < 4 the substance can neither be considered to be bioaccumulative (B) nor very bioaccumulative (vB). Furthermore,one study investigating the potential of metylcyclohexane (CAS No 108-87-2) to accumulate in fish is available. In this study Cyprinus carpio was exposed to test substance concentrations of 10 and 100 µg/L, which resulted in BCF values of 95-321 L/kg and 134-237 L/kg, respectively. These values are substantially lower than the threshold value of 2000 L/kg for bioaccumulating substances, according to the “Guidance on information requirements and chemical safety assessment” (ECHA, 2012). 

Toxicity Assessment

As methylcyclohexane is neither fulfilling the classification criteria for classification as R45, R46, R48, R49, R60-63, nor the screening criterion for Toxicity (T) to aquatic organisms stipulated in the ‘Guidance on information requirements and chemical safety assessment – Chapter R.11: PBT Assessment’ (ECHA, 2012), the substance does not meet the Toxicity (T) criteria.

Likely routes of exposure:

Based on Mackay Level 1 calculation, air is expected to be the target compartment for this substance.