4-tert-butylpyrocatechol

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

In accordance with the screening criteria of the ECHA Guidance on information requirements and chemical safety assessment (Part C and Chapter R.11: PBT assessment):

 

4-TBC is not readily biodegradable but inherently biodegradable with more than 70% of degradation reached in less than 7 days including the log and lag phases (OECD 302B). In addition an abiotic degradation test (OECD 111) showed that 4-TBC was stable in freshwater at pH 4, but unstable at higher pHs 7 and 9, with half-lives of 6 days and < 3.5 days respectively, the underlining phenomenon seemed to be oxidation instead of hydrolysis; and no major degradation products (>10%) were likely to be produced. Therefore, it is considered that 4-TBC does not comply with the P and vP criteria, that is the compound should not be Persistent in the environment.

 

As 4-TBC presents a Log Kow ≤ 4.5 (Log Kow = 1.98), it is assumed that the affinity for the lipids of an organism is insufficient to exceed the B criterion (i.e. BCF value > 2000).

 

4-TBC is neither classified as carcinogenic (Cat. 1, H350 or Cat.2, H351), mutagenic (Cat. 1, H340 or Cat. 2, H341), or toxic to reproduction (Cat. 1, H360 or Cat. 2, H361), nor classified as STOT RE Cat.1, H372 or Cat.2, H373. In acute aquatic toxicity tests, theE/LC50 for fish, daphnids and algae are upper 0.1 mg/L. Furthermore, based on Log Kow ≤ 4.5 (Log Kow of 1.98) and inherent biodegradability, 4-TBC fulfils neither P criteria, nor B criteria. As a result, the PBT assessment can be stopped, the substance being presumably not T.