Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Silicon, primarily in the form of silica and silicates (the transformation forms of elemental silicon) is taken up by living species. Silicic acid is known to be the major bioavailable form for aquatic organisms and it plays an important role in the biogeochemical cycle of Si. Most living organisms contain at least trace quantities of silicon. For some species Si is essential element taken up actively, while for others Si is not essential but still taken passively and need to be excreted out (or passivated by way or other). Many species like diatom algae, radiolarians, flagellates, sponges and gastropods have silicate skeletal structures.

Silica is very ubiquitous in the aquatic and terrestrial environments. Measured silicon concentration values in biota are available for a variety of systems. These observations have shown no tendency or low intrinsic tendency of dissolved or undissolved silica to bioaccumulate in aquatic or terrestrial species if silicon is not taken up actively. Sufficient evidence exists to show that no further bioaccumulation studies are needed for silicon.