undecan-2-one; methyl nonyl ketone

Endpoint summary

Description of key information

Hydrolysis

The half-life of the test chemical was determined at different pH range. Test vessel was incubated in the dark at 25°C for 30 days. The half-life value of test chemical was determined to be >30 days at pH 5, 7 and 9, respectively and at a temperature of 25°C. Material balance ranges from 87.5 to 100.8% of the applied radioactivity. Based on this, it is concluded that the chemical was considered as stable in water.

 

Biodegradation in water

Biodegradation study was conducted for evaluating the biodegradation potential of test chemical (A.M. Apia et. al., 2019). The study was performed in accordance with the OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test) under aerobic conditions. Activated sludge was used as a test inoculum. The percentage degradation of test chemical was determined to be 85.4% degradation using CO2 evolution parameter in 28 days. Thus, test chemical was considered to be readily biodegradable in water.

Biodegradation in water and sediment

In accordance with column 2 of Annex IX of the REACH regulation, testing for this endpoint is scientifically not necessary and does not need to be conducted since the test chemical is readily biodegradable.

Biodegradation in soil

In accordance with column 2 of Annex IX of the REACH regulation, testing for this endpoint is scientifically not necessary and does not need to be conducted since the test chemical is readily biodegradable.

Bioaccumulation: aquatic / sediment

The bioaccumulation study was conducted for estimating the BCF (bioaccumulation factor) value of test chemical. The bioaccumulation factor (BCF) value was calculated using a logKow of 4.09 and a regression-derived equation. The estimated BCF (bioaccumulation factor) valueof test chemical was determined to be 28 dimensionless, which does not exceed the bioconcentration threshold of 2000, indicating that the chemical is considered to be non-accumulative in aquatic organisms.

Adsorption / desorption

The adsorption coefficient Koc in soil and in sewage sludge of test chemical was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The solutions of the test substance and reference substances were prepared in appropriate solvents. A test chemical solution was prepared by accurately measuring 4μL of test item and diluted with acetonitrile up to 10 ml. Thus, the test solution concentration was 330 mg/l. The pH of test substance was 5.4. Each of the reference substance and test substance were analysed by HPLC at 210 nm. After equilibration of the HPLC system, Urea was injected first, the reference substances were injected in duplicate, followed by the test chemical solution in duplicate. Reference substances were injected again after test sample, no change in retention time of reference substances was observed. Retention time tR were measured, averaged and the decimal logarithms of the capacity factors k were calculated. The graph was plotted between log Koc versus log k.The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and therewith, log Koc of the test substance was determined from its measured capacity factor. The reference substances were Acetanilide, 4-chloroaniline, 4-methylaniline(p-Tolouidine), N-methylaniline, p-toluamide, Aniline, 2,5-Dichloroaniline, 4-nitrophenol, 2 - nitrophenol, 2 -nitrobenzamide, 3 - nitrobenzamide, Nitrobenzene, 4-Nitrobenzamide, 1-naphthylamine, 1-naphtol, Direct Red 81, Benzoic acid methylester, Carbendazim, Benzoic acid phenylester, Xylene, Ethylbenzene, Toluene, Naphthalene, 1,2,3-trichlorobenzene, Pentachlorophenol, Phenol, N,N-dimethylbenzamide, 3,5-dinitrobenzamide, N-methylbenzamide, Benzamide, phenanthrene, DDT having Koc value ranging from 1.25 to 5.63. The Log Koc value of test chemical was determined to be 2.747 ± 0.000 at 25°C. This log Koc value indicates that the test chemical has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.

Additional information

Hydrolysis

The half-life of the test chemical was determined at different pH range. Test vessel was incubated in the dark at 25°C for 30 days. The half-life value of test chemical was determined to be >30 days at pH 5, 7 and 9, respectively and at a temperature of 25°C. Material balance ranges from 87.5 to 100.8% of the applied radioactivity. Based on this, it is concluded that the chemical was considered as stable in water.

 

In addition to this, as per in accordance with column 2 of Annex VIII of the REACH regulation, testing for this endpoint is scientifically not necessary and does not need to be conducted since the test chemical is readily biodegradable.

Biodegradation in water

Various experimental studies and predicted data of the test chemical were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental study from peer reviewed journal (A.M. Apia et. al., 2019), biodegradation study was conducted for evaluating the biodegradation potential of test chemical. The study was performed in accordance with the OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test) under aerobic conditions. Activated sludge was used as a test inoculum. The percentage degradation of test chemical was determined to be 85.4% degradation using CO2 evolution parameter in 28 days. Thus, test chemical was considered to be readily biodegradable in water.

 

Another biodegradation study was carried out for evaluating the percentage biodegradability of test chemical (from handbook, peer reviewed journal and authoritative databases). Activated sludge was used as test inoculums obtained from 3 treatment plants of different sizes and designs and fed by different sewage systems. Initial test substance conc. used for the study was 500 mg/l and conc. of the inoculum used was 2,500 mg/l, respectively. Warburg constant temperature respirometer was used as a test vessel. The suspended solid conc. was adjusted to 2,500 mg/l by removal of supernatant liquid or by addition of tap water. The sludge was not washed. No mineral salts were added. The sludge suspension was blended for 10 sec and 20 ml were pipetted into 125 ml Warburg flasks containing the test substance (substrate).  A control flask for measurement of endogenous respiration was included with each run. Readings were made for 24 hr at 0.5 to 5 hr interval, depending on the rate of oxygen uptake. The experimental results were plotted as accumulative oxygen uptake corrected for endogenous respiration. %ThOD of the test chemical was determined to 21.8% by activated sludge in 24 hrs. Thus, based on this, test chemical was considered to be readily biodegradable in nature.

 

In a supporting study from peer reviewed journal (Robert M. Gerhold, 1962), biodegradation experiment was carried out for evaluating the percentage biodegradability of test chemical. Activated sludge was used as test inoculums obtained from 3 treatment plants of different sizes and designs and fed by different sewage systems. Initial test substance conc. used for the study was 500 mg/l and conc. of the inoculum used was 2,500 mg/l, respectively. Test chemical (substrates) easily soluble in water were made up in 0.1 per cent concentration with distilled water and stored at 6°C until needed. Warburg constant temperature respirometer was used as a test vessel. They were modified 125 ml Erlenmeyer flasks fitted with 1.5 ml center-wells and female ground glass joints. Warburg flasks were cleaned by the following procedure: (a) flasks were rinsed once with tap water, and dried In the 103°C oven; (b) flasks were washed with two rinses of chloroform to remove fats and greases, then dried; (c) the flasks were submerged in potassium dichromate cleaning solution for 24 hr, rinsed In the same manner as the pipettes, and dried in an inverted position. Each flask received 10 ml of substrate solution or suspension delivered with a volumetric pipette. Next, 10 ml of blended sludge were added to each flask. The final concentration of substrate was 500 mg/liter. The final concentration of sludge solids was 2500 mg/liter. The control for endogenous respiration contained 10 ml of distilled water and 10 ml of adjusted sludge. Endogenous respiration was defined as the amount of accumulative O2uptake observed in the control flask containing sludge and distilled water. After 10-20 min of shaking for temperature equilibration the flasks were closed off to the atmosphere and shaken for 24 hr at 78 oscillations per min. From 9 to 16 readings were made during each experiment. The terms "percentage oxidized," or "percentage of oxidation," or "X per cent oxidized" mean the ratio of the amount of oxygen taken up by the sludge in the presence of that concentration of the substrate to the amount of oxygen required for complete oxidation of that concentration of substrate, i.e., oxidation to carbon dioxide, water, nitrate, and sulfate. This ratio is also referred to as the "percentage of total theoretical oxygen demand (ThOD)."Theoretical O2 uptake of the test chemical Methyl nonyl ketone by activated sludge was determined to be1503 mg/l. Percentage degradation of the test chemical was determined to be 26.9% by Brookside culture, 12.3% by Columbus culture and 26.2% by Hilliard culture in 24 hrs. Thus, the chemical was considered to be readily biodegradable in water.

 

For the test chemical, biodegradation study was carried out for 28 days for evaluating the percentage biodegradability of test chemical (Secondary source, 2008. The study was performed according to OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test) under aerobic conditions. Sewage plant effluent was used as a test inoculum for the study. Sodium benzoate was used as a reference substance for the study. The test system was shown to be viable (acceptable degradation of a model substrate, sodium benzoate) and test chemical was shown not to inhibit the biological degradation of the model substrate. The percentage degradation of test chemical was determined to be 25% by using CO2 evolution parameter in 28 days. Thus, based on percentage degradation, test chemical was considered to be not readily biodegradable in water.

 

In a prediction done using Estimation Programs Interface Suite, the biodegradation potential of the test chemical in the presence of mixed populations of environmental microorganisms was predicted. 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 readily biodegradable.

 

In an another study from peer reviewed journal and secondary source, biodegradation experiment was conducted for evaluating the biodegradation potential of test chemical. Study was performed under using M. smegmatis (bacteria) as a test inoculum. These cultures were kindly furnished by Ruth Gordon, Institute of Microbiology, Rutgers University, New Brunswick, N. J. Test medium contains (NH4)2SO4, 1.0 g; Na2CO3, 0.1 g; KH2PO4, 0.5 g; MgSO477H20, 0.2 g; CaCl2, 10 mg; FeSO4-7H20, 5 mg; MnSO4, 2 mg; Cu, 50 Mg (as CuSO4.5H20); B, 10 Ag (as H3BO3); Zn, 70 ,ug (as ZnSO4.7H20); Mo, 10 MAg (as MoO3); pH 7.0. Water washed agar was added when solid media were desired. Washed cellular suspensions were prepared from liquid cultures, using 0.067 M phosphate buffer (pH 7) as the suspension fluid and test chemical was added at 0.2% (v/v). Test chemical was estimated photometrically by means of the colorimetric reaction. The oxygen uptake (O2 uptake) by the test bacteria of test chemical in 30 mins was evaluated to be 89. Thus, the bacterial cells were able to rapidly oxidize the test chemical and hence, chemical was considered to be biodegradable in water.

 

Overall, it can be concluded that the test chemical was considered to be readily biodegradable in water.

Biodegradation in water and sediment

In accordance with column 2 of Annex IX of the REACH regulation, testing for this endpoint is scientifically not necessary and does not need to be conducted since the test chemical is readily biodegradable.

Biodegradation in soil

In accordance with column 2 of Annex IX of the REACH regulation, testing for this endpoint is scientifically not necessary and does not need to be conducted since the test chemical is readily biodegradable.

Bioaccumulation: aquatic / sediment

Various data of the test chemical were reviewed for the bioaccumulation end point which are summarized as below:

 

In a study from authoritative databases, the bioaccumulation study in fish was conducted for estimating the BCF (bioaccumulation factor) value of test chemical. The bioaccumulation factor (BCF) value was calculated using a logKow of 4.09 and a regression-derived equation. The estimated BCF (bioaccumulation factor) value of test chemical was determined to be 28 dimensionless.

 

In a prediction done using the BCFBAF model (v3.01) of Estimation Programs Interface, the bioconcentration factor (BCF) of test chemical was predicted. The bioconcentration factor (BCF) of test chemical was estimated to be 9.801 L/kg whole body w.w at 25°C.

 

Using Chemspider database, the bioconcentration Factor (BCF) of test chemical was evaluated. The bioconcentration factor of test chemical was estimated to be 873.9 dimensionless at both pH 5.5 and 7.4 respectively.

 

Further, SciFinder database (American Chemical Society (ACS) was used for predicting the bioconcentration factor (BCF) of test chemical. The bioconcentration factor (BCF) of test chemical was estimated to be 686 dimensionless at pH range 1-10 respectively at 25°C.

 

From CompTox Chemistry Dashboard using OPERA (OPEn (quantitative) structure-activity Relationship Application)  V1.02 model in which calculation based on PaDEL descriptors (calculate molecular descriptors and fingerprints of chemical)  the bioaccumulation i.e BCF for test chemical was estimated to be 18.5 dimensionless . The predicted BCF result based on the 5 OECD principles. Thus based on the result it is concluded that the test chemical was considered to be non-bioaccumulative in nature.

 

On the basis of above results for test chemical, it can be concluded that the BCF value of test chemical was evaluated to be ranges from 9.8 to 873.9, which does not exceed the bioconcentration threshold of 2000, indicating that the test chemical is not expected to bioaccumulate in the food chain.

Adsorption / desorption

Experimental studies and predicted data of the test chemical were reviewed for the adsorption end point which are summarized as below:

 

In an experimental study from study report, the adsorption coefficient Koc in soil and in sewage sludge of test chemical was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The solutions of the test substance and reference substances were prepared in appropriate solvents. A test chemical solution was prepared by accurately measuring 4μL of test item and diluted with acetonitrile up to 10 ml. Thus, the test solution concentration was 330 mg/l. The pH of test substance was 5.4. Each of the reference substance and test substance were analysed by HPLC at 210 nm. After equilibration of the HPLC system, Urea was injected first, the reference substances were injected in duplicate, followed by the test chemical solution in duplicate. Reference substances were injected again after test sample, no change in retention time of reference substances was observed. Retention time tR were measured, averaged and the decimal logarithms of the capacity factors k were calculated. The graph was plotted between log Koc versus log k.The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and therewith, log Koc of the test substance was determined from its measured capacity factor. The reference substances were Acetanilide, 4-chloroaniline, 4-methylaniline(p-Tolouidine), N-methylaniline, p-toluamide, Aniline, 2,5-Dichloroaniline, 4-nitrophenol, 2 - nitrophenol, 2 -nitrobenzamide, 3 - nitrobenzamide, Nitrobenzene, 4-Nitrobenzamide, 1-naphthylamine, 1-naphtol, Direct Red 81, Benzoic acid methylester, Carbendazim, Benzoic acid phenylester, Xylene, Ethylbenzene, Toluene, Naphthalene, 1,2,3-trichlorobenzene, Pentachlorophenol, Phenol, N,N-dimethylbenzamide, 3,5-dinitrobenzamide, N-methylbenzamide, Benzamide, phenanthrene, DDT having Koc value ranging from 1.25 to 5.63. The Log Koc value of test chemical was determined to be 2.747 ± 0.000 at 25°C. This log Koc value indicates that the test chemical has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.

 

Another adsorption study was conducted for determining the adsorption coefficient value of test chemical (Secondary source, 2008). Study was performed in accordance with the OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)). HPLC grade methanol and distilled water, buffered to pH 7.0, were used to prepare the eluting solvent. The mixture was degassed before use. The test material was dispersed in this methanol and injected in duplicate (0.13g in 10 ml); the quantities injected were 0.26μg. The following reference substances were also injected: 8.6 μg Phenol, 9.6 μg Atrazine, 9.0 μg Napthalene, 8.8 μg 1,2,3-Trichlorobenzene, 12.8 μg Dichlofopmethyl, 7.5 μg DDT and 48.8 μg Sodium Nitrate. HPLC was performed on test chemical and the reference substances. A chromatography system consisting of an RI and UV detector was used to calculate retention times. Calibration graphs were generated for log k against log Koc for the reference compounds and from this, Koc values for test chemical could be deduced. The active substance seems to be degraded during the HPLC measurement. The adsorption coefficient (Koc) value of the 4 test samples by HPLC method was determined to be 95 (logKoc = 2.01), 1350 (logKoc = 3.13), 2655 (logKoc = 3.42) and 74131 (logKoc = 4.87) mL/g or L/Kg.

 

In a study from authoritative databases, adsorption study was conducted for estimating the adsorption coefficient (Koc) value of test chemical. The adsorption coefficient (Koc) value was calculated using astructure estimation method based on molecular connectivity indices. The adsorption coefficient (Koc) value of test chemical was estimated to be 278 (Log Koc = 2.44). This Koc value indicates that the test chemical has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.

 

For the test chemical from secondary source and PPDB database, adsorption study was conducted for determining the adsorption coefficient value of test chemical. Study was performed in sodium azide-sterilized sandy loam, clay loam, sand, and silt loam soils, respectively. The adsorption coefficient (Koc) value of test chemical was determined to be 2480 (logKoc = 3.39). This log Koc value indicates that the test chemical has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.

 

In aprediction done using theKOCWIN Programof Estimation Programs Interface was used to predict the soil adsorption coefficient i.e Koc value of test chemical. The soil adsorption coefficient i.e Koc value of test chemical was estimated to be 301.1 L/kg (log Koc= 2.47) by means of MCI method at 25 °C. This Koc value indicates that the test chemical has a moderate sorption to soil and sediment and therefore has slow migration potential to ground water.

 

On the basis of above overall results for test chemical, it can be concluded that the log Koc value of test chemical was evaluated to be ranges from 2.4 to 3.4, respectively, indicating that the test chemicalhas a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.