Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Endpoint summary

Administrative data

Description of key information

Additional information

There are no reliable data on aquatic toxicity of potassium hydroxide. The substance is known to be a strong alkaline substance that dissociates completely in water to K+ and OH- (OECD SIDS potassium hydroxide, 2002). Also, data on pH increases due to the addition of potassium hydroxide in the water used in the test, are lacking. In many tests reports there were no data on pH, buffer capacity and/or test medium composition, although this is essential information for toxicity tests with KOH.

However, the only posssible effect of potassium hydroxide would result from the pH effect. However pH is expected to remain between environmentally acceptable ranges.

As stated in the OECD SIDS of potassium hydroxide (2002)(p4), it was not considered usefull to derive a generic PNEC, as the buffer capacity, the pH and the fluctuation of the pH are very specific for a certain ecosystem and show considerable differences. A significant increase of the pH of the receiving water is not expected. Generally, the change in pH of the recieving water should stay within a tolerated range of the pH at the effluenct side and for this reason no adverse effects on the aquatic environment are expected due to the production or use of potassium hydroxide, if emissions of waste water are controlled by appropriate pH limits and/or dilutions in relation to the natural pH and buffering capacity of the receiving water.

The effects of KOH on the aquatic compartement are expected to be comparable to the effects of NaOH. Available data on NaOH indicate that concentrations of 20-40 mg/L may be acutely toxic to fish and invertebrates (single species tests). Data on pH increases due to the addition of these amounts of NaOH in the used test waters are lacking. In waters with a relatively low buffering capacity, NaOH concentrations of 20-40 mg/L may result in a pH increase with one to several pH units (EU RAR, 2007; section 3.2.1.1.3, page 30).