5-[(2-hydroxyethyl)amino]-o-cresol

Toxicity to aquatic algae and cyanobacteria

Description of key information

The toxicity of the test item to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD 201 and GLP. The aim of the study was to assess the effects on growth rate and yield over a period of 72 hours. The study was conducted under static conditions with an initial cell density of 5297 cells/mL. Based on the preliminary test 5 concentrations levels were tested in a geometrical series with a dilution factor of 2 (nominal): 6.25 - 12.5 - 25.0 - 50.0 - 100 mg/L corresponding to the geometric mean measured concentrations: 5.52 - 12.1 - 24.0 - 48.1 - 83.4 mg/L. Three replicates were tested for each test item concentration and six replicates for the control. The environmental conditions (pH, light intensity and room temperature) were within acceptable limits. The concentration of test item were analytically verified by LC-MS/MS at start of exposure (0h) and the end of the exposure (72h) as well as 24 and 48h of all test concentrations and control. The measured concentrations at start and after 24h were in the range of 91 to 104%, after 48h 81 to 91% and at the end of the exposure in the range of 72 to 98% of the nominal values. All the validity criteria were fulfilled according to the OECD guideline 201.

All effect values given are based on geometric mean measured concentrations of the test item. NOECr=5.52 mg/L, LOECr=12.1 mg/L, ErC10=10.8 (10.5 -11.0) mg/L, ErC20=12.1 (11.9 -12.3) mg/L, ErC50=15.9 (15.7 -16.2) mg/L. NOECy= 5.52 mg/L, LOECy=12.1 mg/L, ErC10=9.63 (7.06-10.9) mg/L, ErC20=10.0 (7.23-11.1) mg/L, ErC50=11.3 (7.77-11.8) mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

15.9 mg/L

EC10 or NOEC for freshwater algae:

10.8 mg/L