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Short-term toxicity to fish

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Description of key information

96-h (4-d) LC50 for freshwater fish: >22 µg/l

Key value for chemical safety assessment

Additional information

A 96-hour LC50 of >22 µg/l has been determined for the effects of the test substance on mortality of Oncorhynchus mykiss. A 14-day LC50 value was determined in the same test of 10 µg/l (Springborn Laboratories 1990a). This 14-d value is derived from a prolonged acute toxicity test and is not relevant for PNEC derivation nor classification and labelling purposes.

A Bayer 1991 study reports a 14-day LC50of >51.7 µg/l. At day 14 in the 34.2 µg/l concentration, 50% of the fish were displaying sub-lethal effects (irregular swimming behaviour and tumbling during swimming), and at day 11 in the 51.7 µg/l concentration all the fish were displaying sub-lethal effects (reduced feed acceptance, fish mainly at the bottom, aggravated breathing and lying on side/back). This test was conducted in an open system and test solutions were prepared using a solvent. However, the study author reports that no adverse effects were seen during days 1-10 when the test concentration was maintained at 33 µg/l. On days 12-14 the dosing system malfunctioned resulting in concentrations higher than the solubility. During this period 5/10 fish showed unusual swimming behaviour. It therefore cannot be ruled out that the malfunction of the dosing system contributed to the effects observed.

Dow Corning Corporation (2008) conducted a 14-day toxicity study with Oncorhynchus mykiss and reported an LC50 (14 d) of 17 µg/l based on mortality. This value is derived from a prolonged acute toxicity test and is not relevant for PNEC derivation nor classification and labelling purposes.

 

Springborn Laboratories (1990b), conducted a 14-day study with the marine species Cyprinodon variegatus and reports an LC50 (96 h) >6.3 µg/l based on mortality and an LC50 (14 d) >6.3 µg/l based on mortality. The method to prepare the test medium was the same as the one adopted in Springborn Laboratories 1990a, however in salt water the highest dose achievable was even lower at 6.3 µg/l. No effects were seen at this highest concentration tested. Therefore, 96-hour and 14-day LC50 values of >6.3 µg/l have been determined for the effects of the test substance on mortality of Cyprinodon variegatus.

The results of a prolonged acute test (18-d) gave a 96-hour LC50 of >23 µg/l for the effects of the substance on mortality of small (1 gram) Oncorhynchus mykiss under flow-through conditions. An 18-day LC50 of >31 µg/l was determined for mortality of larger (>3 gram) fish (Dow Corning Corporation, 1992c).

Six other test results report toxicity results greater than the limit of solubility of the registered substance:

96 h LL50: >1000 mg/l (Fundulus heteroclitus) (Firmin, R. et al.(1984)).

96 h LL50: >500 mg/l (Brachydanio rerio(new name: Danio rerio) (Firmin, R. et al.(1984)).

96 h NOELR: >1041 mg/l (Leuciscus idus melanotus) (Bayer AG (1990)).

96 h LL50: >1000 mg/l (Oncorhynchus mykiss) (Firmin, R. et al.(1984)).

96 h LL50: >1000 mg/l (Lepomis macrochirus) (Firmin, R. et al.(1984)).

96 h LL0: 200 mg/l (Leuciscus idus) (Bayer AG (1998)) (Reliability 4).