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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Description of key information

The acute toxicity of Cyclaprop towards Daphnia magna was investigated according to OECD Guideline 202 under GLP. Daphnids were exposed to nominal concentrations of 11, 17, 25, 37 and 56 mg/l under flow-through conditions and observed for 48 hours. Based on measured concentrations, the 48h-EC50 was found to be >14 mg/l, the maximum solubility in the test medium obtained in this test. This is based on the fact that at test initiation, an oily-slick was noted on the surface of the solutions in the mixing chambers of the higher test concentrations. At test termination, this phenomenon was observed for all treatment groups. Presence of the oily-slick appears to indicate that test concentrations exceeded functional solubility in the test system. In addition, floating daphnids were noted in the treatment groups throughout the test and at much higher frequencies than noted in the negative control. This floating is indicative for the presence of oil. Despite the uncertainties on whether the immobility is physical or systemic the EC50 is considered to be a worst case concentration. In view of the efforts made during the experimental design further testing is not expected to change this conclusion.  

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
14 mg/L

Additional information