Registration Dossier

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

The respiration inhibition of activated sludge was investigated using a scanning respirometer. The 2 h IC50 was determined to be 71 mg/L (nominal). The toxicity of hydroquinone to Pseudomonas putida was determined by measuring the cell multiplication inhibition. A 16 h TT (EC3)=58 mg/L nominal was obtained.

Key value for chemical safety assessment

EC50 for microorganisms:
71 mg/L
EC10 or NOEC for microorganisms:
58 mg/L

Additional information

The respiration inhibition of activated sludge was investigated using a scanning respirometer. A luminescence-based scanning respirometer, using a ruthenium (II) complex as the oxygen-sensing element, was employed to monitor the toxicity of phenolic chemicals to activated sludge. The ruthenium (II) complex was irradiated with an excitation light source and the resulting light emission was then sensed and transmitted by an optical fiber connected to a photomultipler tube. The light intensities sensed at a specific wavelength could be related to the dissolved oxygen concentrations in the samples. The 2 h IC50 was determined to be 71 mg/L (nominal).

The toxicity of hydroquinone to Pseudomonas putida was determined by measuring the cell multiplication inhibition. The cultures were inoculated at 25°C for 16 h under static conditions. The concentration of the bacterial suspension was measured turbidimetrically. A 16 h TT (EC3)=58 mg/L nominal was obtained.

The toxicity of hydroquinone to Microcystis aeruginosa was investigated by determining the cell multiplication inhibition threshold concentration. The cultures of M. aeruginosa were exposed to hydroquinone for 8 d under static conditions. The concentration of the algal suspension was determined turbidimetrically. A 8 d TT (EC3)=1 mg/L nominal was found.