Octadecyl stearate

Endpoint summary

Description of key information

Biodegradation in water:

Estimation Programs Interface Suite was run to predict the biodegradation potential of the test compound in the presence of mixed populations of environmental microorganisms. The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI LInear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that test chemical is expected to be not readily biodegradable.

Additional information

Biodegradation in water:

Predicted data for the target compound and various supporting weight of evidence studies for its closest read across substance were reviewed for the biodegradation end point which are summarized as below:

The first study was predicted data study in this the Estimation Programs Interface Suite was run to predict the biodegradation potential of the test compound in the presence of mixed populations of environmental microorganisms. The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI LInear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that test chemical is expected to be not readily biodegradable.

In a supporting weight of evidence study from authoritative database, biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test chemical. The study was performed according to OECD Guideline 301 B "Ready Biodegradability: Modified Sturm Test (CO2 evolution)" at a temperature of 22±2°C. Bacteria collected from activated sludge of the sewage treatment plant of CH 4153 Reinach on 2/6/89 was used as a test inoculum. Initial test substance conc. used in the study was 11.3 and 23.9 mg/l, respectively. The test medium was prepared according to the method described in the guideline. 2-liter flasks equipped with gas inlet and magnetic stirrers were used as the test vessels. Aeration consisted of approx. 25 ml/min air free of carbon dioxide. 1200 ml of the mineral solution with the inoculum was aerated for 24 hours in the test vessel. In 300 ml mineral solution 0.5 ml nonylphenol 10E05PO (solution of 30 mg in 100 ml bidist. Water) and 16.3 rsp. 29.9 mg of test substance were added and homogenized. This solution was given to the test vessel which was immediately connected to the CO2 traps. The biodegradation was calculated on the basis of the theoretical carbon content of the test substance and the cumulative quantities of carbon dioxide determined on the days of measurements. Determination of the initial CO2 of the 0.05 N sodium hydroxide and the C02, absorbed in the absorbers filled with 200 ml 0.05 N sodium hydroxide on the days 7, 10, 13, 17, 20, 24, 27, and 28. Blank consisted of water as specified in the guideline containing 0.5 ml of the nonylphenol 10E05PO solution. 20 mg/L with 0.5 ml of the nonylphenol 10E05PO was used as a reference substance in the study. The percentage degradation of test substance was determined to be 15 and 2% by CO2 evolution parameter in 28 days at a chemical conc. of 11.3 and 23.9 mg/l, respectively. Thus, based on percentage degradation, test chemical is considered to be not readily biodegradable in nature.

 

The next biodegradation study was conducted in accordance with OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test) for 28 days for evaluating the percentage biodegradability of test substance. Mixed culture was used as test inoculum for the study. Inoculum was collected form waste water treatment plant. Initial test substance conc. used in the study was 5-10 mg/l based on ThOD .  The percentage degradation of test substance 18 % by oxygen uptake parameter in 28 days. Thus, based on percentage degradation, test chemical is considered to be not readily biodegradable in nature.

On the basis of above results for target chemical and for its read across substance, it can be concluded that the test substance can be expected to be not readily biodegradable in nature.