Registration Dossier

Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

The key study carried according to OECD Guideline provides a 48h-EC0 value above 1.61 mg/L (meas. Initial).

Key value for chemical safety assessment

Additional information

Solubility and stability of HDI Trimer MEKO-blocked in water

The test material was insoluble in water (far from 100 mg/L). Thus, test material meets the definition of poorly water soluble mixture and has to be considered as a "difficult mixture to test" according to OECD Guidance No 23 (2000) on aquatic toxicity testing of difficult substances and mixtures.

Nevertheless, the registered substance (HDI Trimer MEKO-blocked) with a half-life of 139 d (for pH 7 and 25 °C, calculated from experimental data at 50, 65 and 80 °C), is stable in water for short-term testing.

Study design of Daphnia ecotoxicity testing on HDI Trimer MEKO-blocked (Weyers, 2007)

Test solutions were prepared by direct addition of test material to dilution water (nominal concentration = 100 mg/L), then treated with an ultra turrax for 30 sec at 8000 rpm and afterwards stirred for 24 h on a magnetic stirrer. Undissolved particles were removed by filtration using an aseptic filter of pore size 0.2 µm. The limit concentration of the test item was determined by HPLC resulting in initial concentration of 1.612 mg/L.

The preparation of the test solutions met recommendations from OECD Guidance No 23 (2000):

i. solution concentration higher than theoretical water solubility limit to achieve the maximum dissolved substance

ii. separation of undissolved test substance from the test solution

iii. direct addition to water and use of mixing techniques such as shaking and stirring

Results of Daphnia ecotoxicity (Weyers, 2007)

No immobilisation was recorded during the test. No perturbation of test medium was reported. The dissolved oxygen concentration has been more than 3 mg/L at the end of the test.

Conclusion

Results are expressed as % of initial concentrations. Recovery rates correspond to 2.35 % and 2.48 % of nominal values at 24 and 48 h, respectively.