Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Based on the study report of O'Connor 2002 (key study), the adsorption/desorption potential of the submission item could not be determined experimentally by the HPLC method due to surface-active properties of the substance leading to interferences with the column. An estimation of the organic carbon-water partitioning coefficient (Koc) by a QSAR method on the basis of the Kow revealed a log Koc value of greater than 4.24. Although computational estimations may potentially overestimate the Koc, this calculated value was considered as a reasonable worst case estimation given that the substance may occur in an ionised form under environmental pH conditions. This is because the amine groups present on the test substance will be ionised at pH values found in the environment and the cationic species tend to bind strongly to soil due to partitioning onto organic matter or interactions with clay minerals. In conclusion, it can be expected that the substance has the potential to adsorb to soil and sediment particles under environmental conditions.

The conduct of a Koc study based on the batch-equilibrium method is being waived, as (1) the log Pow based Koc QSAR result, as well as (2) the fact that the substance tends to form cationic species under environmentally relevant pH conditions, unanimously point in one direction and support the worst case assumption that the substance is immobile in soil. The QSAR result for the Koc of 17400 therefore shall be considered as valid for the use in risk assessment. As the conduct of a batch-equilibrium study for further Koc determination only can be expected to confirm the already obvious, the study shall be waived for be not being scientifically necessary.

The low vapour pressure of the substance results in a low Henry's Law constant of the submission item, which makes it unlikely that the substance will be released from water surfaces to the atmosphere in significant amounts.