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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Long-term toxicity to fish

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Administrative data

Link to relevant study record(s)

Description of key information

In water (including soil or sediment pore water), NaOH is present as the sodium ion (Na+) and hydroxyl ion (OH-), as solid NaOH rapidly dissolves and subsequently dissociates in water (EU RAR, 2007; section 3.1.3, page 24).

Key value for chemical safety assessment

Additional information

No valid long-term toxicity studies to fish are available. Despite of this, there is no need for further toxicity testing with NaOH, as all available tests resulted in a rather small range of toxicity values (chronic toxicity test > or = 25 mg/L) and there are sufficient data on pH ranges that are tolerated by major taxonomic groups (EU RAR, 2007, section, page 30).

The OECD SIDS (2002) assigned a low code of reliability ('invalid' or 'not assignable') to all available tests, as in general the tests were not conducted according to the current test guidelines (EU RAR, 2007; section, page 30). Furthermore, 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 NaOH. This is the most important reason why most of the tests were considered 'invalid'.