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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

EC50 for freshwater algae:
207 mg/L
EC50 for marine water algae:
207 mg/L

Additional information

The tetrahydroxy silane is stabilized in the solution with PEG at a very low pH (0,65). When entering into the environment, the pH of the compound will change as a consequence of the dilution.


Due to a strong dependance on pH and concentration which leads to a dynamic polymerisation-depolymerisation equilibrium with speciation into a variety of mono-, oligo., and polymeric anions and amorphous silica, calculations on the distribution in various environmental compartments are not feasible.


The contribution of anthropogenic inputs to the occurrence in the various compartments will be negligible compared to the concentrations contributed to by the natural silica flux.


Dissolved silica from commercial soluble silicates is indistinguishable from natural dissolved silica.


Dead sedimenting diatoms also contribute significantly to sediment silica (diatomaceous earth). Silica is found in all natural waters with an average concentration of 10-20 mg SiO2/l.


Therefore, it can be concluded that the substance doesn’t pose a risk to the aquatic environment.