Reaction mass of (R)-cyano(3-phenoxyphenyl)methyl rel-(1R,3R)-3-((1Z)-2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropanecarboxylate and (R)-cyano(3-phenoxyphenyl)methyl rel-(1S,3S)-3-((1Z)-2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropanecarboxylate

Short-term toxicity to aquatic invertebrates

Description of key information

48 h EC50=0.38 µg/L to daphnids (Daphnia magna), Williams&Thompson

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.38 µg/L

Additional information

The 24 and 48 hour median effective concentrations of cyhalothrin to freshwater crustaceans (Daphnia magna) were determined under static test conditions at a temperature of 20.0±1.0 °C. The protocol is comparable to OECD 202 standards and was conducted under GLP.

Acetone was used as a solvent in preparation of the test solutions. The maximum concentration present in the test solutions was 0.5 mL/L.

The test animals were during 48 hours at 20.0±1.0 °C exposed to nominal test item concentrations of 0.032, 0.056, 0.1, 0.18, 0.32, 0.56, 1.0, 1.8, 3.2, and 10.0 µg/L and in parallel to control and solvent control. The analytical dose verification revealed 69.6 to 118.8% recovery at the beginning and 45.6 to 75.0% at the end of exposure and the losses amounted more than 20% to the initial measurement in most cases. However the effects were assigned to the measured initial concentrations, which results in slightly elevated threshold concentrations if compared to recent standards of OECD 202 (2004).The median effective concentration (EC50) was defined as the concentration, calculated from the data obtained, resulting in immobilisation of 50% of the daphnids in the time period specified. It is to remark that immobilisation was assessed without agitation of the test vessels which results in slightly reduced threshold concentrations if compared to recent standards of OECD 202 (2004). Thus the deviations to recent standards may compensate each other and are accordingly considered of little impact on the results, which are regarded valid and conclusive.

The values obtained, and their 95% confidence limits were: 24 hour EC50 = 2.4 (1.7 - 3.3) 48 hour EC50 as 0.38 (0.29 - 0.50) µg/L. These values were based on the measured concentrations at the start of the test.