Sodium hydroxide

Toxicity to aquatic plants other than algae

Administrative data

Endpoint:

toxicity to aquatic plants other than algae

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
The following reasoning for not conducting further aquatic toxicity studies with NaOH is given in the OECD SIDS Document: The hazard of NaOH for the environment is caused by the hydroxyl ion (pH effect). For this reason the effect of NaOH on the organisms depends on the buffer capacity of the aquatic or terrestrial ecosystem. Also the variation in acute toxicity for aquatic organisms can be explained for a significant extent by the variation in buffer capacity of the test medium. LC50 values ranged between 33 and 189 mg/l. Because the buffer capacity, pH and the fluctuation of the pH are very specificfor a certain ecosystem it was not considered useful to derive a PNEC. For this reason there is no need for additional toxicity testing with NaOH.