Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Piperazine is a solid with low vapor pressure 39 Pa at 23 °C. From the vapour pressure and a water solubility of 150 g/L, a Henrys law constant of 0.022 Pa*m3/mol can be calculated, giving a partitioning coefficient between air-water of 9.3*10-6. This implies that volatilisation from water is low.

The substance has a very low octanol-water partition coefficient (log Kow = -1.25) and it is ionisable and will be present as the cation under pH conditions encountered in the environment which indicates that it will have a low potential for uptake in aquatic organisms. A BCF of less than 3.9 L/kg was observed in the Nite study from 1979.

Data on adsorption/desorption shows that adsorption is not related to the organic content in soil, but rather a cation-exchange mechanism. For risk assessment the mean Kd measured of 14.4 L/kg is used for the partitioning to soil, sediment and suspended particles.

The substance is not hydrolysable, due to its chemical structure. Piperazine is rapidly and completely biodegraded in the environment. The number of competent organisms in the inoculum of the ready test appears to decide whether >60% biodegradation is observed within 28 days and if the 10 d (14d for OECD 301D) window criterium can be fulfilled. Based on the fact that the validity criteria of the ready test is formally not met, we consider piperazine as not readily biodegradable as worst-case.