Nonan-4-olide

Biodegradation in water: screening tests

Description of key information

Read-Across, OECD Guideline 301F, GLP, key study, validity 1:
82% biodegradation after 28 days, meeting the 10-day window.
Readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

γ-nonalactone is a linear saturated 4-hydroxycarboxylic acid derived-lactone with 9 carbons. γ-decalactone is structurally similar compound of aliphatic lactones with 10 carbons. This substance is considered adequate for read-across purpose.

Three studies are available to assess the biodegradation of γ-nonalactone.

The first study, assess as a reliable key study, was performed on γ-decalactone in an aerobic aqueous media, according to OECD Guideline 301F. γ-decalactone was exposed to activated sewage sludge micro-organisms at a concentration of 100 mg/L with culture medium in sealed culture at 22°C for 28 days. The degradation of γ-decalactone was assessed by the measurement of daily oxygen consumption. Control solutions with inoculum and the reference substance, aniline, together with a toxicity control were used for validation purposes. γ-decalactone attained 82% degradation after 28 days, meeting the 10-day window, and therefore should be considered to be readily biodegradable.

The second study, assess as a not assignable supporting study, was performed on γ-nonalactone in an aerobic aqueous media, according to OECD Guideline 301 C. Due to the lacks of many endpoints required such as pH measurement or details on inoculum preparation, the reliability of this study cannot be evaluated. γ-nonalactone was exposed to activated sludge prepared by mixing three fresh samples at a concentration of 100 mg/L at 20°C for 28 days. The degradation of γ-nonalactone was assessed by the measurement of daily oxygen consumption. Control solutions with inoculum and the reference substance, aniline, was used for validation purposes. The degradation rate of the reference substance (aniline) started late (after 6 days only) but reached 10% after 7 days and 70% degradation after 28 days. γ-nonalactone attained 80% degradation after 28 days and therefore should be considered to be readily biodegradable.

 

The third study, assess as a reliable supporting study, was performed on γ-nonalactone, according to OECD Guideline 301 D. γ-nonalactone was exposed to activated sewage sludge (domestic) at a concentration of 2.84 mg/L. The degradation of γ-nonalactone was assessed by the determination of the oxygen consumption. Greater than 60% biodegradation of γ-nonalactone was reached on Day 21 and on Day 28, the biodegradation was 71%. However, γ-nonalactone did probably not meet the 14-day window.

 

In conclusion, based on a read-across approach and data available on γ-nonalactone, this substance is considered readily biodegradable.