Registration Dossier

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

At the highest nominal test concentration of 1000 mg/L in an respiration inhibition test an inhibition rate of 84.8% was found. Based on measured inhibition rates, the 3-hour EC50 was calculated to be 107.6 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:
107.6 mg/L
EC10 or NOEC for microorganisms:
13.6 mg/L

Additional information

The Toxicity of Acetyl acetone (99.8% pure) to Activated Sludge was assessed in a Respiration Inhibition Test according to OECD Guideline 209. The activated sludge microorganisms were exposed to the test item for three hours in a closed system with a headspace of air and intensively mixing. Concentrations of 10, 32, 100, 320 and 1000 mg Acetyl acetone/L (nominal were used). 3,5-Dichlorophenol served as a reference substance and two inoculum controls were used. The 3-hour EC50 for the positive control 3,5-Dichlorophenol, which was tested in the same way as the test item, was found to be 8.5 mg/L and is within the range of 5 - 30 mg/L recommended by the test guidelines; thus, confirming suitability of the activated sludge.In comparison to the inoculum controls the respiration rate of the activated sludge was inhibited by 6.5 and 19.6% at the two lowest nominal concentrations of 10 and 32 mg/L, respectively. At the next higher nominal concentrations of 100 and 320 mg/L, the respiration rate was moderately inhibited by 54.3 and 76.1%. At the highest nominal test concentration of 1000 mg/L an inhibition rate of 84.8% was found. Based on measured inhibition rates, the 3-hour EC50 was calculated to be 107.6 mg/L (Feil, IBACON 2010).

In the cell multiplication inhibition test the effect of 2,4-pentanedione on microorganisms was studied. In the bacterial strain Pseudomonas putida the toxicity threshold (TT = EC3) after a 16 h exposure period has been determined to be 67 mg/l indicating only slight to moderate toxicity in this specific bacterial strain.

In the same investigation the flagellate protozoa Entosiphon sulcatum proved to be more sensitive as demonstrated by the determined toxicity threshold (TT = EC3) of 11 mg/l after a 72 h exposure period (Bringmann and Kuehn 1980). [modified from OECD SIDS Dossier]