Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Dicyandiamide is stable to hydrolysis at pH 4.0, 7.0, and 9.0.

The substance was not readily biodegradable in a screening test according to OECD test guideline 301E, but is degradable in soils (abiotic and biotic degradation). Based on a weight of evidence approach a DT50 in soils of 11.1 days at 20 °C was determined as key value.

In surface water (pelagic test design, OECD guideline 309) no biological degradation of dicyandiamide could be demonstrated (DT50 for primary biological degradation was calculated to be > 1000 d).

Because of the log octanol-water partition coefficient of -1.0, its high water-solubility, and due to its polar nature and pKa, dicyandiamide will not adsorb to soil and sediment hence can be considered to be mobile in the environment.

For the same reasons dicyandiamide will not be taken up by fish gills or across other biological membranes. Therefore, dicyandiamide will not bioaccumulate.

The chemical safety assessment according to REACH Annex I indicates no need to further investigate the environmental fate and behaviour of dicyandiamide and/or its degradation products.

Additional information