p-tert-butylcinnamaldehyde

Short-term toxicity to aquatic invertebrates

Description of key information

The acute toxicity of p-tert-butylcinnamaldehyde to Daphnia magna is estimated to give a 48 hour EC50 of 1.8 mg/L based on read-across from an appropriate analogue substance.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.8 mg/L

Additional information

An appropriate structural analogue, 3-(4-tert-butylphenyl)propionaldehyde (tradename Bourgeonal), has been tested for short-term toxicity to aquatic invertebrates. The method followed was designed to be compatible with the US EPA Draft Ecological Effects Test Guidelines OPPTS 850.1010 (April 1996) and the OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphnia sp, Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008. Following a preliminary range-finding test, twenty daphnids (4 replicates of 5 animals) were exposed to an aqueous solution of the test item at concentrations of 1.0, 1.8, 3.2, 5.6 and 10 mg/L for 48 hours at a temperature of 20 to 21ºC under semi-static test conditions. The number of immobilized Daphnia were recorded after 24 and 48 hours. Chemical analysis of the freshly prepared test preparations at 0 and 24 hours showed measured test concentrations to range from 89% to 97% of nominal. A decline in measured test concentrations was observed in the old or expired test media at 24 and 48 hours in the range of 60% to 83% of nominal. Given this decline in measured test concentrations it was considered justifiable to base the results on the time-weighted mean measured test concentrations. The 48-Hour EC50 value based on the time-weighted mean measured test concentrations was 1.8 mg/L with 95% confidence limits of 1.7 -2.0 mg/L. The No Observed Effect Concentration was 0.77 mg/L.

The study was performed in compliance with GLP and in accordance with recognised standardised guidelines, the study was assigned a reliability score of 2 in line with the principles defined in Klimisch et al (1997) as the study was performed on a structural analogue of the registered substance. Due to the structural similarities between the two substances, it was considered appropriate to use data from the source substance to represent the target substance (for further details see read-across justification document, attached in section 13).