Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Acetonitrile is expected to exist solely as a vapor in the ambient atmosphere. Acetonitrile is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life of this reaction in air has been estimated to range from 20-620 days. An overall half-life for acetonitrile in the troposphere of about 42 days has been estimated considering both the OH radical and ozone reaction rate constants (USEPA, 1987). However, based on average tropospheric conditions reported by Klopffer (1988), this number would be about one year (321 days) according to the 2000 EU Risk Assessment for acetonitrile. Acetonitrile absorbs light only in the far UV regions, and therefore is not expected to be susceptible to direct photolysis by sunlight.

Hydrolysis is unimportant to the aquatic fate of acetonitrile.

Additional information