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PBT assessment

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PBT assessment: overall result

Reference
Name:
Methylhydrazine
Type of composition:
legal entity composition of the substance
State / form:
liquid
Reference substance:
Composition 1
PBT status:
the substance is not PBT / vPvB
Justification:

The substance does not meet the P/vP criteria neither the B/vB criteria and fulfils the T criterion. Therefore, the substance is not PBT / vPvB.

Bioaccumulation: On the basis of physicochemical properties (small molecular weight, extreme water solubility, negative log Kow: -1), toxicokinetic properties (transformation into metabolites that are themselves reactive and do not bioaccumulate: most likely hydrazine and formaldehyde) and a total of three consistent BCF predictions (EPIsuite, Caesar: 0.90, 2 and 3.162 L/kg or dimensionless), no bioaccumulation in animals, including aquatic species, is anticipated for MMH. Therefore the substance is considered as non-B.

Persistence: In water, DT50 values are below the thresholds for the P criterion of Annex XIII. No reliable data were available on soil and sediment compartments, but they were considered not critical for persistence assessment. Moreover, the atmosphere was not a relevant compartment for persistence assessment due to minor distribution and Annex XIII does not propose a threshold to conclude on persistence in the atmosphere.

Overall, data on water compartment (the major compartment according to distribution estimates related to the identified uses) are considered quite representative and sufficient for a definitive conclusion at this tonnage level: non-P.

Toxicity: MMH clearly fulfils the T criterion, both for human health (being a carcinogen) and environment (due to high toxicity to water organisms).

Full details / justifications can be found in the PBT assessment record.