Acrylonitrile

Sediment toxicity

Link to relevant study record(s)

Reference

Endpoint:

sediment toxicity: long-term

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

The scope for contamination of sediments with acrylonitrile is small, given that acrylontitrile is rapidly biodegradable under relevant conditions and entry routes to the aquatic compartment are limited to and mitigated by passage through STP. Moreover the adsorption tendency of acrylonitrile is low and sediments are therefore not expected to act as a sink for acrylonitrile entering surface waters. In the absence of a measured SDO endpoint a PNEC for the freshwater sediment compartment has been derived by applying the conservative default assumptions of the Equilibrium Partitioning Method (EPM) to the aquatic toxicity dataset. Since acceptable risk has been demonstrated in the Chemical Safety Report for the sediment compartment, based on the conservative surrogate EPM-derived PNECsediment value, it can be concluded (as per REACH Annex X - 9.5.1 - Column 2) that a study to determine long-term toxicity to a sediment-dwelling organism is not necessary.

Description of key information

No data are available and no testing is proposed.  A waiver is appropriate for this endpoint on the basis of very low exposure of sediment to acrylonitrile.

Additional information

No data are available and no testing is proposed. A waiver is appropriate for this endpoint on the basis of very low exposure of sediment. Acrylonitrile will be biodegraded in WWTP; any low levels of acrylonitrile present in aquatic emissions will not be expected to accumulate in sediment based on the physicochemical properties of the substance (Koc and water solubility). Sediment dwelling organisms will therefore be exposed to acrylonitrile in the aqueous phase.