2-(4-tert-butylphenyl)-6-cyano-5-[bis(ethoxycarbonylmethyl)carbamoyloxy]-1H-pyrrolo[1,2-b][1,2,4] triazole-7-carboxylic acid 2,6-di-tert-butyl-4-methylcyclohexylester

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

According to Regulation (EC) No. 1907/2006, a substance must fulfill all three criteria for persistence, bioaccumulation and toxicity to be considered as PBT, as listed in part 1 of Annex XIII, and it must fulfill the criteria for persistence and bioaccumulation stated in part 2 of Annex XIII to be considered vPvB. 

Data for the definitive conclusion on the PBT or vPvB properties according to the criteria set in Regulation (EC) No. 1907/2006, Annex XIII, parts 1 and 2, are not available for all three criteria. Thus, the screening criteria given in the ‘Guidance on information requirements and chemical safety assessment - Chapter R.11: PBT assessment’ (ECHA, 2012) are used as surrogate information to decide whether the substance may potentially fulfil the PBT or vPvB criteria.

Persistence (P) Assessment:

A valid screening criterion to evaluate persistence (P) is the potential of a substance for ready biodegradability. 2-(4-tert-butylphenyl)-6-cyano-5-[bis(ethoxycarbonylmethyl)carbamoyloxy]-1 H-pyrrolo[1 ,2-b][1 ,2,4]triazole-7-carboxylic acid-2,6-di-tert-butyl-4-methyl-cyclohexyl ester (UC-141) is not readily biodegradable (11% biodegradation in 28 days). In the absence of other degradation data, the Persistent (P) or very Persistent (vP) criteria cannot be excluded for this substance. 

Bioaccumulation (B) Assessment:

In the absence of experimental bioaccumulation data, the log Kow value obtained for this substance, determined to be 7.7, indicates that UC-141 has bioaccumulation potential and therefore the Bioaccumulative (B) criterion cannot be excluded. Nevertheless, the information gathered on physicochemical properties and metabolism in combination with the QSAR-estimated BCF values provide evidence (in accordance to the REACh Regulation (EC) No 1907/2006, Annex XI General rules for adaptation of the standard testing regime set out in Annexes VII to X, 1.2, to cover the data requirements of Regulation (EC) No. 1907/2006, Annex IX) to state that this substance is likely to fulfil the Bioaccumulative (B) but not the very Bioaccumulative (vB) criteria (see IUCLID section 5.3.1 for details).

Toxicity (T) Assessment:

No adverse effects were reported in the test conducted with UC-141 on algae. The no-observed effect concentration (NOEC value) was determined to be ≥ 100 mg/L (nominal) and ≥0.01 mg/L (measured), and the substance is not classified as carcinogenic, mutagenic or toxic for reproduction nor is there any evidence of chronic toxicity according to the 2nd ATP of Regulation (EC) No. 1272/2008 (CLP) and Directive 67/548/EEC. Therefore, UC-141 does not meet the T criterion according to Regulation (EC) No. 1907/2006, Annex XIII.

Since UC-141 does not meet the T or vB criterion, it is considered not to be PBT or vPvB.