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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

One reliable key study is available on the potassium salt of the registered reaction mass. The limit test shows no toxicity up to the highest concentration tested and therefore the 72h EC50 (growth rate) for algae is higher than 100 mg/L and the 72h NOEC is above or equal to 100 mg/L .

Key value for chemical safety assessment

Additional information

One reliable key study is available on freshwater algae for the potassium salt of the registered reaction mass.

The reaction mass IBAP and its potassium salt have high water solubility and their behavior in water and biological systems is dominated by their ionization. The main assumption is that the potassium cation is not significant in respect of the toxicological effect on aquatic organisms which are expected to be related to the IBAP. In experimental dilute aqueous conditions at environmental pH (5-9), the salt will be completely dissociated and will not behave differently to the parent acid, at identical concentration of the particular speciated form present.

In a 72 hour acute toxicity study, the cultures of desmodesmus subspitacus were exposed to Kalium-isobutylphosphate at a nominal concentration of 100 mg/L (limit test) under static conditions in accordance with the OECD TG 201 and GLP with minor deviations.

No growth rate and biomass inhibition were observed in the treated groups and the validity criteria's were fulfilled.The results on effects are expressed in nominal concentration of test item because the analytical measurement based on phosphate show that it was stable among the study (98% recovery after 72h).

The72h ErC50(growth rate)was determined above 100 mg/L and the 72h NOEC (growth rate) above or equal 100mg/L.

For the purpose of risk assessment, PBT/vPvB assessment and classification and labeling, the concentration was not corrected for the target substance because the molecular weight of potassium was assessed to be negligible compared to the molecular weight of the other constituents of the reaction mass.

According to the CLP and DSD regulations criteria,the reaction mass would not be classified based on acute toxicity results on algae.