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Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: screening tests
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification
Justification for type of information:
The supporting QMRF report has been attached
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Principles of method if other than guideline:
The data is predicted using the OECD QSAR toolbox version 3.3 with logKow as the primary descriptor.
GLP compliance:
not specified
Specific details on test material used for the study:
- Name of test material :3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate
- Molecular formula: C14H24O2
- Molecular weight: 224.342 g/mol
- Smiles notation : C(OC\C=C(\CC\C=C(/C)C)C)(C(C)C)=O
- InChl : 1S/C14H24O2/c1-11(2)7-6-8-13(5)9-10-16-14(15)12(3)4/h7,9,12H,6,8,10H2,1-5H3/b13-9+
- Substance type:Organic
- Physical state: Liquid
Oxygen conditions:
aerobic
Inoculum or test system:
other: Microorganisms
Duration of test (contact time):
28 d
Parameter followed for biodegradation estimation:
other: BOD
Key result
Parameter:
other: % degradation (BOD)
Value:
90.5
Sampling time:
28 d
Remarks on result:
other: Other details not known
Details on results:
Test substance undergoes 90.5% degradation by BOD in 28 days.

The prediction was based on dataset comprised from the following descriptors: BOD
Estimation method: Takes average value from the 5 nearest neighbours
Domain  logical expression:Result: In Domain

((((((((("a" or "b" or "c" or "d" or "e" )  and ("f" and ( not "g") )  )  and ("h" and ( not "i") )  )  and "j" )  and "k" )  and ("l" and ( not "m") )  )  and "n" )  and ("o" and ( not "p") )  )  and ("q" and "r" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Esters (Chronic toxicity) by US-EPA New Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Alkene AND Allyl AND Carboxylic acid ester AND Isopropyl by Organic Functional groups

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Allyl AND Carboxylic acid ester AND Isopropyl AND Overlapping groups by Organic Functional groups (nested)

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Aliphatic Carbon [CH] AND Aliphatic Carbon [-CH2-] AND Aliphatic Carbon [-CH3] AND Carbonyl, aliphatic attach [-C(=O)-] AND Ester, aliphatic attach [-C(=O)O] AND Miscellaneous sulfide (=S) or oxide (=O) AND Olefinic carbon [=CH- or =C<] AND Tertiary Carbon by Organic functional groups (US EPA)

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Carbonic acid derivative AND Carboxylic acid derivative AND Carboxylic acid ester by Organic functional groups, Norbert Haider (checkmol)

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OASIS v.1.3

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >> Michael-type addition on alpha, beta-unsaturated carbonyl compounds OR AN2 >> Michael-type addition on alpha, beta-unsaturated carbonyl compounds >> Four- and Five-Membered Lactones OR AN2 >> Shiff base formation after aldehyde release OR AN2 >> Shiff base formation after aldehyde release >> Specific Acetate Esters OR AN2 >> Shiff base formation for aldehydes OR AN2 >> Shiff base formation for aldehydes >> Haloalkane Derivatives with Labile Halogen OR Non-covalent interaction OR Non-covalent interaction >> DNA intercalation OR Non-covalent interaction >> DNA intercalation >> DNA Intercalators with Carboxamide Side Chain OR Radical OR Radical >> Generation of reactive oxygen species OR Radical >> Generation of reactive oxygen species >> Thiols OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitro Azoarenes OR SN1 OR SN1 >> Nucleophilic attack after carbenium ion formation OR SN1 >> Nucleophilic attack after carbenium ion formation >> Specific Acetate Esters OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitro Azoarenes OR SN2 OR SN2 >> Acylation OR SN2 >> Acylation >> Specific Acetate Esters OR SN2 >> Acylation involving a leaving group  OR SN2 >> Acylation involving a leaving group  >> Haloalkane Derivatives with Labile Halogen OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom >> Haloalkane Derivatives with Labile Halogen OR SN2 >> Alkylation, ring opening SN2 reaction OR SN2 >> Alkylation, ring opening SN2 reaction >> Four- and Five-Membered Lactones OR SN2 >> DNA alkylation OR SN2 >> DNA alkylation >> Alkylphosphates, Alkylthiophosphates and Alkylphosphonates OR SN2 >> Nucleophilic substitution at sp3 Carbon atom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Specific Acetate Esters by DNA binding by OASIS v.1.3

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OECD

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Michael addition OR Michael addition >> P450 Mediated Activation of Heterocyclic Ring Systems OR Michael addition >> P450 Mediated Activation of Heterocyclic Ring Systems >> Furans OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Alkyl phenols OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Arenes OR Michael addition >> Polarised Alkenes-Michael addition OR Michael addition >> Polarised Alkenes-Michael addition >> Alpha, beta- unsaturated esters OR SN1 OR SN1 >> Carbenium Ion Formation OR SN1 >> Carbenium Ion Formation >> Allyl benzenes by DNA binding by OECD

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Biodegrades Fast by Biodeg probability (Biowin 1) ONLY

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Does NOT Biodegrade Fast by Biodeg probability (Biowin 7) ONLY

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Non-Metals by Groups of elements

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Alkali Earth OR Halogens by Groups of elements

Domain logical expression index: "n"

Similarity boundary:Target: CC(C)C(=O)OCC=C(C)CCC=C(C)C
Threshold=10%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as (!Undefined)Group All Lipid Solubility < 0.01 g/kg AND (!Undefined)Group C Surface Tension > 62 mN/m by Skin irritation/corrosion Exclusion rules by BfR

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as Group All log Kow > 9 OR Group C Aqueous Solubility < 0.0001 g/L OR Group C Melting Point > 55 C OR Group C Molecular Weight > 350 g/mol OR Group C Vapour Pressure < 0.0001 Pa by Skin irritation/corrosion Exclusion rules by BfR

Domain logical expression index: "q"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 200 Da

Domain logical expression index: "r"

Parametric boundary:The target chemical should have a value of Molecular weight which is <= 278 Da

Validity criteria fulfilled:
not specified
Interpretation of results:
readily biodegradable
Conclusions:
The test chemical 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate was estimated to be readily biodegradable in water.
Executive summary:

Biodegradability of 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate (CAS no. 2345 -26 -8) is predicted using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor (2017). Test substance undergoes 90.5% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical

3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate was estimated to be readily biodegradable in water.

Description of key information

Biodegradability of 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate (CAS no. 2345 -26 -8) is predicted using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor (2017). Test substance undergoes 90.5% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical

3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate was estimated to be readily biodegradable in water.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

Various predicted data for the target compound 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate(CAS No. 2345-26-8) and various supporting weight of evidence studies for its read across substances 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 chemical3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate(CAS No. 2345-26-8) was estimated.Test substance undergoes 90.5% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate 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 compound 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate(CAS No. 2345-26-8) 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 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate is expected to be readily biodegradable.

 

In a supporting weight of evidence study from authoritative database (J-CHECK, 2017) for the read across chemical methyl (3 -oxo-2 -pentylcyclopentyl)acetate (CAS no. 24851 -98 -7),biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance methyl (3 -oxo-2 -pentylcyclopentyl)acetate. 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 was determined to be 98, 91 and 100% by BOD, TOC removal and GC parameter in 28 days. Thus, based on percentage degradation, methyl (3 -oxo-2 -pentylcyclopentyl)acetate is considered to be readily biodegradable in nature.

 

For the another read chemical 1,2-Benzenedicarboxylic acid, di-2-propenyl ester (CAS no. 131-17-9) from peer reviewed journal (Ryuichiro KURANE et. al; 1977), biodegradation study was conducted for evaluating the percentage biodegradability of read across substance 1,2-Benzenedicarboxylic acid, di-2-propenyl ester (CAS no. 131-17-9). Pseudomonas acidovorans 256-l (microorganism) was used as a test inoculum. Microorganisms were isolated from soil and waste water by enrichment shaking culture at 30°C, using DEHP as a sole carbon source. Microorganisms were purified by successive streak transfers on four kind of medium, i.e., DEHP agar, nutrient agar, Rich-agar and Poor-agar medium. After precultivation on DEHP slant agar for 2 days, three loops of cells were inoculated into 500ml flasks containing 150ml of the medium containing DEHP as a sole carbon source, and cultivated with rotary shaker at 30°C. Phthalate esters were usually extracted with n-hexane, which were extracted with chroloform), and estimated with a Shimadzu gas chromatograph (model GC-5A). The columns used were a glass column of 3.0 mm in inside diameter, 2m in length, packed with Silicone OV-17 on 60/80 mesh Uniport B or Silicone SE-52 on 60/80 mesh Uniport B.Water-soluble TOC of culture broth was estimated with a Beckman model 915 TOC analyzer after extraction with n-hexane and centrifugation at 28,000g for 30min.The percentage degradation of read across substance was determined to be 100% degradation by GC parameter in 2 days. Thus, based on percentage degradation,1,2-Benzenedicarboxylic acid, di-2-propenyl ester is considered to be readily biodegradable in nature.

 

Another biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of read across substance 1,2-Benzenedicarboxylic acid, di-2-propenyl ester (CAS no. 131-17-9) (OECD SIDS, 2004). The study was performed according to OECD Guide-line 301 C "Ready Biodegradability: Modified MITI Test” under aerobic conditions at a temperature of 25 ± 1°C.Test inoculum activated sludge was obtained from four sewage treatment works, three rivers, one lake, and two bays in Japan. For inoculum preparation, each 500 ml of the collect fresh samples from the ten sites and 5 l of the activated sludge which have been previously used were mixed. The mixture was adjust to pH 7.0 ± 1.0 and was aerated in a fill-and-draw activated sludge vessel. Thirty minutes after stopping aeration, discard about one third of the whole volume of supernatant and add an equal volume of a solution (pH 7.0 ± 1.0) containing 0.1 % each of glucose, peptone and potassium orthophosphate, to the settled material and recommence aeration. Thus procedure was repeated one per day. Initial test substance conc. used in the study was 100 mg/l. The medium was prepared by the method described in the JIS K0102:1986 21.Suspended solids concentration used for the study was 30 mg/l. Culturing apparatus consists of closed system for measuring of oxygen demand with 300 ml culture medium bottles, CO2-absorbers, temperature controller, and respirometers. Aerobic conditions was obtained using the magnetic stirrers. All tests were performed in triplicates. Aniline was used as a reference substance for the study. Reference substance aniline undergoes 64 and 81% degradation by using BOD parameter at 7 and 14 days, respectively. The percentage degradation of test substance was determined to be in the range of 76-92% degradation by BOD and %degradation parameter in 28 days. Thus, based on percentage degradation,1,2-Benzenedicarboxylic acid, di-2-propenyl ester is considered to be readily biodegradable in nature.

 

On the basis of above results for target chemical 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate (CAS No. 2345-26-8) (from OECD QSAR toolbox version 3.3 and EPI suite, 2017) and for its read across substance (from authoritative database J-CHECK, 2017, peer reviewed journal and secondary source OECD SIDS, 2004), it can be concluded that the test substance 3,7-dimethylocta-2,6-dien-1-yl 2-methylpropanoate can be expected to be readily biodegradable in nature.