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PBT assessment

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PBT assessment: overall result

Type of composition:
legal entity composition of the substance
State / form:
solid: bulk
Reference substance:
PBT status:
the substance is not PBT / vPvB

The PBT assessment of N-Acetyl-DL-tryptophan (CAS 87-32-1) is based on the criteria set out in the “Guidance on information requirements and chemical safety assessment, Chapter R.11: PBT Assessment” (ECHA, 2014).


Based on experimental findings N-Acetyl-DL-tryptophan (CAS 87-32-1) is readily biodegradable (74.6% after 28 d, O2 consumption corrected for nitrification, 301 F). Thus, the substance does not meet the screening criterion for persistence and is therefore not P or vP.



The log Kow of N-Acetyl-DL-tryptophan (CAS 87-32-1) is very low (< -1.7, pH 7, 23 °C, OECD 107). Therefore, the substance does not meet the screening criterion for bioaccumulation and is therefore not B or vB.



The available aquatic effect concentration of N-Acetyl-DL-tryptophan (CAS 87-32-1) for chronic toxicity is ≥ 0.1 mg/L (algae) and is > 0.1 mg/L for acute toxicity (fish, aquatic invertebrates and algae). Furthermore, the substance is readily biodegradable and has a log Kow < 4.5. Therefore, the criteria set out in Annex XIII of Regulation (EC) No 1907/2006 are not met and the substance is not considered to meet the T criterion.

In conclusion, the substance is not PBT/vPvB.