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Short-term toxicity to aquatic invertebrates

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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). Therefore, the only posssible effect would result from the pH effect. However, pH will remain between environmentally expected ranges.

Key value for chemical safety assessment

Additional information

OECD (2002) assigned a low code of reliability to most available aquatic toxicity tests, as in general the tests were not conducted according to the current test guidelines (EU RAR of NaOH, section 3.2.1.1.4, 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.

The tests with aquatic invertebrates resulted in acute LC50 values and toxic/lethal concentrations ranging from 30 to < or = 1000 mg/L.