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Short-term toxicity to aquatic invertebrates

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Description of key information

Acutely harmful to aquatic invertebrates.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
85.4 mg/L

Additional information

To determine the toxicity of 2-ethylhexanoic acid to aquatic invertebrates, a 
non-GLP study following the method laid down in Directive 79/831/EEC using 
Daphnia magna was performed. The calculated EC50 (48h) value in this study was 
85.4 mg/L, related to the nominal concentration (BASF SE 1988). Due to the low 
pH-values in the higher concentrations (125 mg/L = 5.79 (0h), 7.09 (48h)- 62.5 mg/L = 6.95 (0h) 
- 7.85 (48h)) the effects might have occurred due to pH changes induced by the test 
substances. In the concentration 125 mg/L all animals are immobile after 48 hours whereas 
in the concentration 62.5 mg/L only one daphnid was immobile at the test end. In addition a
test with the sodium 2-ethylhexanoat is available. This analogous substance is the product of 
neutralisation of 2-ethylhexanoic acid with aqueous solution of sodium hydroxide. In the test an EC 50
of 910 mg/L was estimated after a test duration of 48 hours. Another acute test performed by DOW (1993) revealed an EC50 (48h) of 109 mg/L.
For the overall assessment of the substance, the lower EC50 value is used.