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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

A measured BCF is not available for icos-1-ene. Log BCF have been calculated on the basis of a log Kow of 10.03 using two QSAR. Calculated log BCF range from 2.04-2.64.

Key value for chemical safety assessment

Additional information

A measured BCF is not available for icos-1 -ene. As the calculated log Kow of icos-1 -ene is >3 the bioaccumulation endpoint cannot be waived. However, ECHA's Guidance on Information Requirements and Chemical Safety Assessment R7c Endpoint Specific Guidance (2008) indicates that before commissioning a new vertebrate test alternative sources of data on the bioaccumulation potential of a chemical should used.

Nonpolar substances have been shown to have a linear relationship between log Kow and BCF in the log Kow range 1 -6. However, at Kow >6 a decreasing relationship is observed. Several QSAR have been developed that calculate the BCF of non-polar, hydrophobic compounds on the basis of their log Kow (e.g. Connell and Hawker, 1988 and USEPA, 2008). Icos-1 -ene falls within the applicability domain of the USEPA QSAR, but slightly outside that of Connell and Hawker. The calculated log BCF range from 2.04 -2.64.

The log Kow of icos-1 -ene has been calculated in KOWWIN (log kow 10.03) and SPARC (log kow 11.65). ECHA's guidance on information requirements and chemical safety assessment - Part C: PBT assessment (2008) states that the aquatic BCF of a substance is probably lower than 2000l/kg if the calculated log Kow is higher than 10. As none of the Kow models have experimental data in this Kow range the reliability of modelled Kow values >10 is not known. However, as both models indicate a log Kow >10 we can conclude that icos-1 -ene is unlikely to bioaccumulate.

Taken together, this information indicates that icos-1 -ene is not expected to bioaccumulate or pose a risk of secondary poisoning.