4-amino-m-cresol

Long-term toxicity to aquatic invertebrates

Description of key information

The NOEC of 4 -amino-m-cresol for adult survival, time of the first brood and juveniles produced per surviving parent, and adult growth are equal to 0.22 mg/L in a  21-day Daphnia magna reproduction study OECD 211.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.22 mg/L

Additional information

A 21-day Daphnia magna reproduction study was conducted to determine the effects of exposure to the test substance 4-amino-m-cresol on Daphnia magna reproduction. The study was conducted in accordance with the OECD Chemicals Testing Guideline No.211 Daphnia magna Reproduction Test (adopted October 2012) and GLP.

The definitive test was conducted at nominal concentrations of 0.0056, 0.018, 0.056, 0.18 and 0.56 mg/L. A control group was also included. The test was conducted using a semi-static design with daily renewal of the test media.

Ten replicate test vessels were prepared for the control and each test concentration. A single juvenile Daphnia magna (<24 hours old) was added to each test vessel.

On renewal occasions, parental animals were transferred into freshly prepared test media. Any juveniles remaining in old test media were counted and the number of juveniles produced per parental animal on any day during the 21-day study duration was recorded. At the end of the test, carapace lengths of all surviving parental Daphnia magna were measured.

Chemical analysis of the freshly prepared media showed measured concentrations to range from 80% to 120% of nominal value with the exception of the 0.018 and 0.56 mg/L test concentrations on Day 0 which showed measured concentrations of 121% of nominal value. However, as the measured concentration was only just above the 120% acceptance limit these results were not considered to affect the

validity of the test. Analysis of the old media showed measured concentrations to range from less than the limit of quantification (LOQ) of the analytical method (assessed as 0.002 mg/L) to 19% of nominal.

Given the decline in measured concentration over each 24-hour renewal period, it was considered justifiable to base the results on time-weighted mean measured test concentrations. These were calculated to be 0.0028, 0.0061, 0.017, 0.069 and 0.22 mg/L.

The NOEC and LOEC of 4-amino-m-cresol in term of adult survival, time of the first brood and juveniles produced per surviving parent, and adult growth are 0.22 mg/L and > 0.22 mg/L, respectively.