1-(2,6-bis(4-tolyl)-1,3-dioxano(5,4-d)-1,3-dioxan-4-yl)ethane-1,2-diol

Long-term toxicity to aquatic invertebrates

Description of key information

Exposure of Daphnia magna to the test material resulted in no significant mortalities at all the test concentrations employed during the test.
The 14 and 21-Day EC50 (immobilisation) values, based on nominal test concentrations for the parental Daphnia generation (P1) were estimated to be greater than 0.40 mg/l.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.13 mg/L

Additional information

Introduction.

A study was performed to assess the effect of the test material on the reproduction of Daphnia magna over a 21-day period. The method followed that described in the OECD Guidelines for Testing of Chemicals No 211 (1998) "Daphnia magna, Reproduction Test", referenced as Method C.20 of Commission Regulation (EC) No. 440/2008.

Methods.

Based on the results of a preliminary range-finding test, Daphnia magna were exposed (10 replicates of a single daphnid per group) to an aqueous solution of the test material over a range of test concentrations of 0.0040, 0.013, 0.040, 0.13 and 0.40 mg/l for a period of 21 days. The test material solutions were prepared by stirring an excess (50 mg/l) of test material in dechlorinated tap water at approximately 1500 rpm at a temperature of approximately 21°C for 24 hours prior to removing any undissolved test material by filtration through a 0.2 µm filter (initial approximate 2 litres discarded) to produce a saturated solution with a nominal concentration of 0.40 mg/l. The remaining test concentrations were prepared by dilution of the saturated solution.

The test solutions were renewed 3 times per week. The numbers of live and dead adult Daphnia and young daphnids (live and dead) were determined daily. The Daphnia were fed daily with an algal suspension.

Results.

The 14 and 21-Day EC₅₀(immobilisation) values, based on nominal test concentrations, for the parental Daphnia generation (P₁) were estimated to be greater than 0.40 mg/l.

The 21-Day EC₅₀ (reproduction) value based on nominal test concentrations was estimated to be greater than 0.40 mg/l.

The "Lowest Observed Effect Concentration" was considered to be 0.40 mg/l on the basis that at this test concentration significantly fewer live young per adult were produced when compared to the control.

The "No Observed Effect Concentration" was considered to be 0.13 mg/l on the basis that at this test concentration there were no significant mortalities (immobilisation) observed in the parental generation (P₁) and that there were no significant differences between the control and the 0.13 mg/l test group in terms of numbers of live young produced per adult by Day 21.

Analysis of the test media was carried out on days 0 (fresh media), 3 and 5 (old and fresh media) which showed measured concentrations to range from 80% to 100% of nominal. Given that there was no loss of test material it was considered appropriate to analyze the old samples only from day 7 onwards. 

Analysis of the test concentrations on days 7, 10, 12, 14, 17, 19 and 21 showed measured concentrations to range from 82% to 114% of nominal with the exception of Day 7 (0.4 mg/l) and Day 10 (0.13 mg/l) which showed measured values of 78% and 47% of nominal respectively. Re-analysis of the corresponding frozen samples showed measured concentrations of 85% and 87% of nominal respectively and so the results are based on nominal concentrations only.