Methyl non-2-enoate

Endpoint summary

Description of key information

Biodegradation in water

Biodegradability of methyl (2E)-non-2-enoate (CAS no. 111 -79 -5) is predicted using OECD QSAR toolbox version 3.3 (2017) with logKow as the primary descriptor. Test substance undergoes 82% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical methyl (2E)-non-2-enoate was estimated to be readily biodegradable in water.

Biodegradation in water and sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound methyl (2E)-non-2-enoate (CAS No. 111 -79 -5). If released in to the environment, 25.3% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of methyl (2E)-non-2-enoate in water is estimated to be 8.66 days (208 hrs). The half-life (8.66 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of methyl (2E)-non-2-enoate in sediment is estimated to be 77.916 days (1870 hrs). Based on this half-life value, it indicates that methyl (2E)-non-2-enoate is not persistent in sediment.

Biodegradation in soil

The half-life period of methyl (2E)-non-2-enoate (CAS No. 111 -79 -5) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 72.5% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of methyl (2E)-non-2-enoate in soil is estimated to be 17.33 days (416 hrs). Based on this half-life value of methyl (2E)-non-2-enoate, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.

Additional information

Biodegradation in water

Various predicted data for the target compound methyl (2E)-non-2-enoate (CAS No. 111-79-5) and supporting weight of evidence studies for its read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction done by SSS (2017) using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor, percentage biodegradability of test chemicalmethyl (2E)-non-2-enoate(CAS No. 111-79-5) was estimated.Test substance undergoes 82% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical methyl (2E)-non-2-enoate was estimated to be readily biodegradable in water.

 

In another prediction using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compoundmethyl (2E)-non-2-enoate(CAS No. 111-79-5) in the presence of mixed populations of environmental microorganisms was estimated.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 chemical methyl (2E)-non-2-enoate is expected to be readily biodegradable.

 

In a supporting weight of evidence study from peer reviewed journal (Alfredo A. Marchetti et. al, 2003) for the read across chemical 1,4-dibutyl (2Z)-but-2-enedioate (CAS no. 105-76-0),biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance1,4-dibutyl (2Z)-but-2-enedioate. The study was performed according to EPA OPPTS 835.3110 (Ready Biodegradability) and EPA OPPTS 835.3120 (Sealed Vessel Carbon Dioxide Production Test), respectively under aerobic conditions. Aerobic sludge was used as a test inoculum obtained from a municipal wastewater treatment facility in Livermore, CA. Initial test chemical concentration used for the study was50 ng/µl. Microcosms were prepared in 250-ml amber glass bottles fitted with Mininert valves (Supelco, Bellefonte, PA) and consisted of 20 ml of fresh aerobic sludge filtered using Whatman No.1 paper (Whatman Inc., Clifton, NJ), 20 ml of water, and 60 ml of nutrient medium with the following composition: KH2PO4, 85.0 mg/l; K2HPO4, 217.5 mg/l; Na2HPO4.2H2O, 33.4 mg/l; NH4Cl, 0.5 mg/l; CaCl2, 27.5 mg/l; MgSO4.7H2O, 22.5 mg/l; FeCl3.6H2O, 0.25 mg/l. Preparation of the nutrient solution was carried out as that described in the US EPA Ready Biodegradability Method. Abiotic microcosms were autoclaved twice, and sodium azide was added to produce a final concentration of 0.05%.On day 0, the microcosm bottles were purged with CO2-free air obtained by scrubbing air with a saturated NaOH solution. Test compounds were then added in 5-µlinjections using a precision syringe. Microcosms were incubated at 30°C and shaken in a Psychotherm controlled-environment shaker. Active microcosms were prepared in triplicate, and abiotic ones in duplicate. Control microcosms without test compounds were also prepared to determine background production of CO2.Benzene was used as a reference substance for the study.CO2 and test compound measurements were performed on days 0, 3, 6, 8, 10, 15, 20, and 28, respectively. Carbon dioxide was measured as methane in a gas chromatograph model 8610c equipped with a methanizer, a 15-cm silica gel column, and a flame ionization detector (FID). Samples of 1 ml of microcosm headspace were drawn for CO2 measurement; 1 ml of oxygen was injected to replace the extracted air. Samples were introduced in the chromatograph through a 250-µl injection loop after the loop was purged with the 1-ml headspace sample. To keep abiotic microcosms sterile, needles were wiped with 70% ethanol before insertion through the valve septum. Calibrations were made using commercially prepared mixtures of 0.369, 1.010, and 20.010 parts per thousand by volume (pptv) of CO2 in air.Test chemical was measured in the liquid phase. Samples of 200µl were taken from the liquid phase of the microcosms using a syringe. These were centrifuged to remove particulates and aliquots of 2–10µl were analyzed using a Micro-Tech Ultra-Plus HPLC system equipped with an XTerra MS C18 column (3.0×150 mm). Methanol and acetic acid were used in this determination were HPLC grade. Aliquots were eluted at a flow rate of 400µl/min using an isocratic mobile phase consisting of 20% water/methanol (97:2) 0.005 mM in sodium acetate, and 80% methanol/water/acetic acid (95:4:1). Analytes were detected with a mass spectrometer model LCQ using an electrospray interface. Instrument parameters were as follows: capillary temperature of 240°C, source voltage of 4.5 kV, sheath gas of 70 units without auxiliary gas, ion trap injection time of 1000 ms, and a microscan value of 1. Analytes were detected in the pseudo MS/MS mode, isolating sodium ions of TGME [M+ Na]+ at. mass 251.3 and DBM adducts [M +Na] + at. mass 229.3 and detecting the same masses without the addition of collision energy. Reference substance Benzene shows the sharpest increase with a slope greater than 0.16 d/1, reaching approx. 55% mineralization by day 6 but then decreases to approx. 40% mineralization by day 8. The mineralized fraction of test chemical increases at a rate of 0.06 d/1 until day 8 and levels off at 65% mineralization. Test chemical was not detectable in the aqueous phase of the active microcosms starting on day 3 (<0.03 ng/µl). The concentration of test chemical measured in the abiotic microcosms was well below that expected from the amount introduced. Read across substance 1,4-dibutyl (2Z)-but-2-enedioate undergoes 100% primary degradation by test mat. analysis within 3 days and 65% degradation by CO2 evolution parameter in 28 days, respectively. Thus, based on percentage degradation, 1,4-dibutyl (2Z)-but-2-enedioateis considered to be readily biodegradable in nature.

 

Another biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of the same read across substance 1,4-dibutyl (2Z)-but-2-enedioate (CAS no. 105-76-0) (OECD SIDS, 1996). The study was performed according to OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test) under aerobic conditions. Test inoculum was obtained from soil. Initial test substance conc. used was in the range of 31.35 – 31.5 mg/l based on DOC. Sodium benzoate was used as a reference substance for the study. An inoculum obtained from soil was incubated with 1,4 -dibutyl (2Z)-but-2 -enedioate. Reference substance Sodium benzoate undergoes atleast 95% degradation within 28 days. The percentage degradation of read across substance 1,4 -dibutyl (2Z)-but-2 -enedioate was determined to be 70% by DOC removal parameter in 10 days. The pass level for ready biodegradability was reached within 10 days. Thus, based on percentage degradation, 1,4 -dibutyl (2Z)-but-2 -enedioate is considered to be readily biodegradable in nature.

 

For the read across substanceMethyl Octanoate (CAS no. 111-11-5) from secondary source (Robert Murray Gerhold, 1962), biodegradation study was carried out for evaluating the percentage biodegradability of read across chemical Methyl Octanoate. 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) which was poorly soluble in water were made up in 0.1 per cent concentration with distilled water and stored at 6°C until needed, but prior to addition to Warburg flasks the substrate suspensions were shaken so as to achieve an even distribution. 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). The percentage degradation of read across substance Methyl Octanoate was determined to be 35.4, 50.2 and 27.1%in 24 hr period by using the activated sludge obtained from three different treatment plants and theoretical O2 uptake of the test chemical was determined to be1264 mg/l, respectively. Thus, based on percentage degradation, chemical Methyl Octanoate was considered to be readily biodegradable in nature.

 

In a supporting weight of evidence study from authoritative database (J-CHECK, 2017 and EnviChem, 2014) for the read across chemical Hedione (CAS no. 24851-98-7), biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance Hedione. The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)). Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of read across substance Hedione was determined to be 98, 91 and 100% by BOD, TOC removal and GC parameter in 28 days. Thus, based on percentage degradation, Hedione is considered to be readily biodegradable in nature.

 

On the basis of above results for target chemicalmethyl (2E)-non-2-enoate(from OECD QSAR toolbox version 3.3 and EPI suite, 2017) and for its read across substance (from peer reviewed journal, authoritative database J-CHECK, EnviChem and secondary source), it can be concluded that the test substancemethyl (2E)-non-2-enoatecan be expected to be readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound methyl (2E)-non-2-enoate (CAS No. 111 -79 -5). If released in to the environment, 25.3% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of methyl (2E)-non-2-enoate in water is estimated to be 8.66 days (208 hrs). The half-life (8.66 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of methyl (2E)-non-2-enoate in sediment is estimated to be 77.916 days (1870 hrs). Based on this half-life value, it indicates that methyl (2E)-non-2-enoate is not persistent in sediment.

Biodegradation in soil

The half-life period of methyl (2E)-non-2-enoate (CAS No. 111 -79 -5) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 72.5% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of methyl (2E)-non-2-enoate in soil is estimated to be 17.33 days (416 hrs). Based on this half-life value of methyl (2E)-non-2-enoate, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.

On the basis of available information, the test substance methyl (2E)-non-2 -enoate can be considered to be readily biodegradable in nature.