Indeno[4,5-d]-1,3-dioxin, 4,4a,5,6,7,8,9,9b-octahydro-7,7,8,9,9-pentamethyl-

Short-term toxicity to aquatic invertebrates

Description of key information

The acute Daphnia study according to OECD TG 202 the EC50 for immobilisation was 3.8 mg/l based on nominal concentrations because the measured concentrations were close to >=80% of the nominal ones. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

3.8 mg/L

Additional information

A study was performed to assess the acute toxicity of the test material to Daphnia magna according to OECD TG 202. Following a preliminary range-finding test, twenty daphnids (2 replicates of 10 animals) were exposed to an aqueous solution of the test material over a range of nominal concentrations of 0.19, 0.34, 0.61, 1.1, 1.9, 3.4, 6.1, 11 and 19 mg/L for 48 hours at a temperature of approximately 21 °C under static test conditions. The test material solutions were prepared by stirring an excess (100 mg/L) of test material in reconstituted water at approximately 2000 rpm at a temperature of 25 °C for 24 hours prior to removing any undissolved test material by filtration (0.2 µm) through a pre-conditioned filter to produce a saturated solution which had a nominal test concentration of 19 mg/L. A series of dilutions was made from this saturated solution to prepare the remainder of the test series. The number of immobilised Daphnia were recorded after 24 and 48 hours. The 48-Hour EC₅₀ for the test material to Daphnia magna based on nominal test concentrations was 3.8 mg/L with 95 % confidence limits of 3.2 - 4.5 mg/L. Analysis of the test preparations at 0 and 48 hours showed measured test concentrations to range from 86 % to 117 % of the nominal values with the exception of the highest test concentrations of 11 and 19 mg/L at 48 hours which, showed measured values of 75 % and 78 % of nominal (80 % and 78 % of nominal from analysis of frozen duplicate samples). As these low values were close to the required 80 % of nominal value and the overall mean measured test concentrations were calculated to range from 85 % to 107 % of nominal it was considered justifiable to base the results on the nominal test concentrations only.