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Short-term toxicity to fish

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Description of key information

LC50 (96 h) Zebra fish > 100 mg/l

Key value for chemical safety assessment

LC50 for freshwater fish:
100 mg/L

Additional information

The short term toxicity to fish was tested on CAS 4193-55-9, but only the test summaries are available. Several studies are reported in a Weight of Evidence approach, with reliability 4. All studies agree in considering the substance as non toxic to fish for acute exposure, with LC50 > 100 mg/l.

A test conducted on the sodium/potassium salt (CAS 70942-01-7) analogous was chosen; no signs of toxicity were recorded up to 100 mg/l, after 96 hours of exposure. The analogous substances have the same organic functionalities of the substance under registration, but a different salification: for CAS 70942-01-7 the mixture sodium/potassium is used while for CAS 4193-55-9 only sodium is used. The presence of a complete sodium salification instead than a sodium/potassium mixture of the CAS 4193-55-9 has no impact on general water toxicological properties and the percentage and chemical identity of organic impurities are also very similar (details in Category Justification Report, attached to the section 13).

The remaining tests presented were performed on the analogous dihydroxyethyl derivative tetrasulphonated sodium salt (CAS 16470-24-9); this substance can be considered a conservative representative, since it has the same organic functionalities, but the higher sulphonation let to a higher water solubility, therefore availability in the water compartment. The percentage and chemical identity of organic impurities are also very similar. The Category Justification Report is attached to the section 13 for more details.

Acute toxicity for Zebra fish was evaluated in the 96 hours screening test, according to the OECD guideline 203. Two doses were administrated at 562 and 1000 mg/l with no effect (Ciba - Geigy Ltd., 1992). The study result is supported by other four studies performed between 1973 and 1999 on Zebra fish at 96h, for which only a summary is available indicating LC50 all greater than 1000 mg/l.

Furthermore, a prolonged semistatic assay over 14 days was conducted with Brachydanio rerio. Endpoints were mortality, signs of intoxication, length and weight. The nominal concentrations were 100, 316 and 1000 mg/l. There was no mortality and no difference in body weight at nominal concentrations of 100 and 316 mg/l. Only at 316 mg/l one fish showed slackening in movement (Bayer AG., 1992).

Two fish acute toxicity tests are available (Ciba-Geigy, 1994 and 1998) on CAS 16090-02-1 pre-treated with light in order to obtain a high percentage of photodegraded products and verify their impact on aquatic toxicity. Both tests resulted in a LC50 > 100 mg/l, demonstrating that those degradation products are no more dangerous for the environment than the parent compounds.

In conclusion, no fish acute toxicity is expected for CAS 4193-55-9.