2,2'-methylenebis(6-nonyl-p-cresol)

Short-term toxicity to aquatic invertebrates

Description of key information

48 hour EC50 > 0.18 mg/L, (greater than the maximum solubility) NOEC 0.18 mg/L, OECD 201, EU Method C. 3, ISO  8692 and OECD series on testing and assessment number 23, Migchielsen 2013c.

Additional information

In the key study (Migchielsen, 2013b), the acute toxicity of the test material to Daphnia magna was determined in a study conducted under GLP conditions and in accordance with OECD 202, EU Method C.2, ISO 6341 15 and OECD series on testing and assessment number 23, 2000.

The test was performed as a limit test combined with a range finding study. Due to the limited solubility of the test material in the test medium (M7), WAF’s were prepared at the following loading rates: 1.0, 10 and 100 mg/L and a ten-fold dilution of the 1.0 mg/L WAF.

Analysis of the samples taken from the WAF prepared at 100 mg/L at the start of the test showed a measured concentration of 0.26 mg/L. This concentration decreased to 0.12 mg/L after 48 hours of exposure. The average measured concentration was calculated to correspond to 0.18 mg/L. It was expected that these results represented the maximum soluble concentration in test medium.

Under the conditions of the test, the test material did not induce acute immobilisation of Daphnia magna after 48 hours of exposure at 0.18 mg/L, being the average exposure concentration measured in a WAF prepared at a loading rate of 100 mg/L. This value was therefore considered to be the NOEC. The 48 hour EC50 exceeded 0.18 mg/L (100 mg/L WAF). Due to the very limited solubility of the test material in test medium, concentrations toxic for Daphnia magna could not be reached.