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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Environmental fate & pathways

Phototransformation in water

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Description of key information

Phototransformation in water is expected to be of minor importance since formaldehyde is rapidly converted to a glycol.

Key value for chemical safety assessment

Additional information

In water, formaldehyde is rapidly hydrated to form methylene glycol. Equilibrium almost totally favours the glycol. Incorporated into atmospheric water, formaldehyde or its hydrate can undergo oxidation. When incorporated from air into cloud water, fog water or rain, formaldehyde can react with aqueous hydroxyl radicals in the presence of oxygen to produce formic acid, water and hydroperoxide (aqueous). The formaldehyde glycol can also react with ozone. In comparison to its biodegradability, however, photochemical degradation of formaldehyde in the aqueous phase does not appear to be relevant. Furthermore, studies on the phototransformation in water or soil are not required for a registration under REACH.