Nonan-4-olide

Toxicity to microorganisms

Description of key information

Read-Across, German standard guideline DIN 38412 part 27, WoE, validity 4:
30min-EC50 (Pseudomonas putida) = 800 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

800 mg/L

Additional information

A weight of evidence approach was used with three studies. The first study was performed on the test substance γ-nonalactone (9 carbons) and the second and third studies were performed on a similar substance, γ-decalactone, a linear saturated 4 -hydroxycarboxylic acid derived-lactone with 10 carbons. This substance is considered adequate for read-across purpose.

The first study is a publication (Maruzzella and Bramnick, 1961) which evaluates the antibacterial properties of perfumery chemicals. Two hundred and thirty perfumery chemicals at concentrations from 1/500 to 1/10 000 were tested in vitro against growing cultures of four bacteria (Bacillus subtilis ATCC 9524, Escherichia coli ATCC 1129,Staphylococcus aureus Ox-H (penicillin sensitive) and Staphylococcus aureus ATCC 10390 (penicillin resistante)) at 37°C during 24 hours. The chemicals included: acetals, acids, aldehydes, esters, ethers, ketones, lactones, and miscellaneous compounds. Among these compounds, γ-nonalactone was tested. The results show that γ-nonalactone inhibited only E. coli at 1/500 test concentration. Generaly, inhibitiory activity is estimated to be 14% for the lactones group.

The second study, according to German standard guideline DIN 38412 part 27, was performed to assess the toxicity of γ-decalactone on microorganisms Pseudomonas putida. Five test concentrations were prepared with two controls (control and solvent control) and oxygen consumption was recorded after 30 min of exposure. According to the little information, the 30min-EC50 was evaluated to be 800 mg/L. No sufficient information was provided in this report to assess the fiability of the results.

The third study, not according to international or national guideline, was performed to assess the toxicity of γ-decalactone on the respiration of activated sludge. A limit test was performed at 1000.5 mg/L with activated sludge from a wastewater treatment plant laboratory with municipal wastewater. According to the little information provided in this report, no significant effect is determined at the concentration tested. The respiration rates of blank and test substance were 20 and 26 mg O2/(L*h), respectively. The 30-min EC50 was estimated to be greater than the highest concentration tested of 1000.5 mg/L. No sufficient information was provided in this report to assess the fiability of the results.

Based on the first study, the test substance γ-nonalactone was not considered toxic to microorganism. To have a key value for chemical safety assessment, the result of toxicity on Pseudomonas putida obtained with the surrogate substance γ-decalactone was used: 30min-EC50 at 800 mg/L.