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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Description of key information

EC50 48h Daphnia magna > 113 mg/l

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
113 mg/L

Additional information

One test was performed on the substance under registration (CAS 16324-27-9) (Ciba-Geigy Ltd in 1996), according to OECD guideline 202 on Daphnia magna; at the nominal concentration of 100 mg/l tested, no effects were observed. Nevertheless, the measured concentrations after 48h were less than 20 % of the nominal and geometric mean will result in EC 50 > 53 mg/l.

The substance is part of the Stilbene Fluorescent Whitening Agents category, group 3. The most similar substance can be considered CAS 16470-24-9, the dihydroxyethylamino derivative tetrasulphonated sodium salt. Both substances share the same metabolic and degradation pathway, while the dihydroxy derivative is more water soluble and can also be considered a conservative reference (650 g/l for CAS 16470-24-9 vs 140 g/l for CAS 16324-27-9).

Acute toxicity for Daphnia magna was evaluated on CAS 16470-24-9 in a 48 hours screening test, according to the OECD guideline 202. A single dose was administrated at 100 mg/l (limit test) with no effect.

The result was confirmed by two supporting studies: one performed at just 24h (RCC Umweltchemie AG., 1988) and the other one at 48, but just the summary is available (Solvias AG., 1999), with no effect up to 1000 mg/l.

For the whole category short-term toxicity to aquatic invertebrate was tested for nine over fourteen registered substances and none of the existing tests arisen any concern for aquatic invertebrate toxicity.

As a consequence it can be concluded that no short-term toxicity to aquatic invertebrate is expected also for CAS 16324-27-9. The result of the key study for CAS 16470-24-9 is taken as a reference for risk assessment.