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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Description of key information

Short-term toxicity to aquatic invertebrates: EC50(48h) = 35 mg/L for daphnids, acute toxicity, static  (OECD TG 202).

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
35 mg/L

Additional information

There is no fully reliable study of acute toxicity of CTC on daphnia available. There is a weight of evidence that the EC50-48h must be in the range 10 to 100 mg/L, based on the studies published by Bazin et al., 1987: EC50-24h = 97 mg/L, Knie et al, 1983: LC50 -24h = 28 mg/L and LeBlanc, 1980: EC50-48h = 35 mg/L. The data published by Japanese MoE (EC50-48h = 8.1 mg/L) seems to be an outlier, specially when we consider the fully reliable chronic toxicity study (Thompson, 1997) where it was observed no mortality among parent animals, during 21 days up to the highest tested concentration: 5.7 mg/L (measured).

Consequently, we will use the value from LeBlanc as key value for acute toxicity to invertebrates.