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Ecotoxicological information

Long-term toxicity to fish

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Description of key information

A chronic study in fathead minnow (Pimephales promelas) was conducted. Starting with 24h old eggs, the embryos, larvae and juvenile fish were exposed continuously to estradiol over 92 days post hatch. Hatching success, mortality, growth and sexual differentiations was evaluated as prime
endpoints.
Additionally, adult fathead minnow were exposed to estradiol over a period of 46 days. Fecundity was the main endpoint studied.
Results: Hatching EC10 = 290 ng/L , larval (28 days post hatch) survival EC10 = 530 ng/L, larval length increase EC10 = 160 ng/L,
larval weight increase 83 ng/L; juvenile (92 days post hatch) survival EC10 = 140 ng/L, juvenile length increase EC10 = 48 ng/L, juvenile weight increase EC 10 = 27 ng/L, juvenile (56 days post hatch) weight increase was 8 ng/L. Sexual differentiation was impaire
from a concentration of 60 ngL onwards with an increase in morphological females or immature fish.
Adult reproduction fecundity EC10 =26 ng/L
In a life-cycle study of medaka reported by Seki et al. (2005), the histologically confirmed sex ratio at 60 days post hatch was significantly changed at E2 concentrations ¿ 28 ng/L. No male fish were observed at E2 concentrations of 92 ng/L. Oocytes in the testes (testis-ova) were occasionally
seen at an E2 concentration of 9 ng/L.
Metcalf et al. (2001) observed a concentration-dependent increase of the incidence and the intensity of testis-ova in medaka at E2 concentrations ¿ 10 ng/L after 100 days exposure.

The effects in fish after long-term exposure with estradiol at concentrations below 0.1 µg/L justify the classification as very toxic to aquatic life with long lasting effects.

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater fish:
10 ng/L

Additional information

The study was performed according to GLP (report B945).