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Ecotoxicological information

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Reliable short-term toxicity tests results are available for freshwater fish (Oryzias latipes), invertebrates (Daphnia magna) and algae (Pseudokirchneriella subcapitata) for the silanol hydrolysis product of the registered substance, tert-butyldimethylsilanol (CAS No. 18173-64-3). The relevant short-term values are:

Fish: LL50 (96 h) > 100 mg/l (nominal).

Daphnia: EC50 (48 h): 6.49 mg/l; (nominal).

Algae: ErC50 (72 h): 84.0 mg/l; NOEC 12.5 mg/l (nominal).

The registrant does not hold data for the non-silanol hydrolysis product, piperazine (CAS No. 110-85-0). However, aquatic data were reported in the SIAR (SIDS INITIAL ASSESSMENT PROFILE for Piperazine, CAS 110-85-0, SIAM 18, 20-23 April 2004). The data shows that Daphnia are the most sensitive species to both hydrolysis products of the registration substance, with the silanol hydrolysis product, tert-butyldimethylsilanol, showing higher toxicity than piperazine. Because the substance will only be used under Strictly Controlled Conditions (SCC) the measured data are not used for the purpose of setting PNECs. However, they are used for classification and labelling purposes.