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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
Data is from computational model developed by USEPA
Reference:
Composition 0
Qualifier:
according to
Guideline:
other: Modeling database
Principles of method if other than guideline:
The Biodegradation Probability Program (BIOWIN) estimates the probability for the rapid aerobic biodegradation of an organic chemical in the presence of mixed populations of environmental microorganisms .The model is part of the EpiSuite program of the US-EPA. Estimations are made with BIOWIN version 4.10. Estimates are based upon fragment constants that were developed using multiple linear and non-linear regression analyses. Experimental biodegradation data for the multiple linear and non-linear regressions were obtained from Syracuse Research Corporation's (SRC) data base of evaluated biodegradation data (Howard et. al., 1987). This version (v4.10) designates the models as follows (see also Boethling et al. 2003):Biowin1 = linear probability modelBiowin2 = nonlinear probability modelBiowin3 = expert survey ultimate biodegradation modelBiowin4 = expert survey primary biodegradation modelBiowin5 = MITI linear modelBiowin6 = MITI nonlinear modelBiowin7 = anaerobic biodegradation model
GLP compliance:
not specified
Test material information:
Composition 1
Specific details on test material used for the study:
- Name (IUPAC): (+)-Neomenthol- Molecular formula: C10H20O- Molecular weight: 156.267 g/mol- Smiles notation: C[C@@H]1CC[C@H]([C@H](C1)O)C(C)C- InChl: 1S/C10H20O/c1-7(2)9-5-4-8(3)6-10(9)11/h7-11H,4-6H2,1-3H3/t8-,9+,10+/m1/s1- Substance type: Organic- Physical state: Liquid
Oxygen conditions:
other: aerobic (Biowin 1-6) and anaerobic (Biowin 7)
Inoculum or test system:
other: mixed populations of environmental microorganisms
Details on study design:
Using the computer tool BIOWIN v4.10 by US-EPA (EPIWIN) the aerobic as well as the anaerobic biodegradability of the test material can be estimated. The follwoing seven different models are used by the tool: Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI LInear Model, MITI Non-Linear Model and Anaerobic Model (calles Biowin 1-7, respectively). Due to this results the overall prediction of readily biodegradability is done for the desired chemical.Biowin 1 and 2, are intended to convey a general indication of biodegradability under aerobic conditions, and not for any particular medium. Biowin 1 (Linear model)The fast biodegradation probability for any compound is calculated by summing, for all the fragments present in that compound, the fragment coefficient multiplied by the number of instances of the fragment in the compound (for MW, the value of that parameter is multiplied by its coefficient), and then adding this summation to the equation constant which is 0.7475. The summed values for each fragment coefficient multiplied by the number of instances appear in the "VALUE" column of the linear results screen. Biowin 2 (Non-linear model)Calculation of the fast biodegradation probability for any compound begins by summing, for all the fragments present in that compound, the fragment coefficient multiplied by the number of instances of the fragment in the compound (for MW, the value of that parameter is multiplied by its coefficient), then adding this summation to the equation constant which is 3.0087. The summed values for each fragment coefficient multiplied by the number of instances appear in the "VALUE" column of the non-linear results screen. The non-linear fast biodegradation probability is then calculated from the logistic equation as follows, where total = 3.0087 + the summation as described above:Biowin 3 and 4 yield estimates for the time required to achieve complete ultimate and primary biodegradation in a typical or "evaluative" aquatic environment.Biowin 5 and 6 are predictive models for assessing a compound’s biodegradability in the Japanese MITI (Ministry of International Trade and Industry) ready biodegradation test; i.e. OECD 301C. These models use an approach similar to that used to develop Biowin1 and 2. This protocol for determining ready biodegradability is among six officially approved as ready biodegradability test guidelines of the OECD (Organization for Economic Cooperation and Development). A total dataset of 884 chemicals was compiled to derive the fragment probability values that are applied in this MITI Biodegradability method. The dataset consists of 385 chemical that were critically evaluated as "readily degradable" and 499 chemicals that were critically evaluated as "not readily biodegradable". Biowin 7, the anaerobic biodegradation model, is the most recent. As for the other Biowin models, multiple (linear) regression against molecular fragments was used to develop the model, which predicts probability of rapid degradation in the "serum bottle" anaerobic biodegradation screening test. This endpoint is assumed to be predictive of degradation in a typical anaerobic digester. Biowin7 estimates the probability of fast biodegradation under methanogenic anaerobic conditions; specifically, under the conditions of the "serum bottle" anaerobic biodegradation screening test (Meylan et al. 2007). A total of 169 compounds with serum bottle test data were identified for use in model development. Out of seven different Biowin models, Biowin model 3 and 4 will help in estimating biodgeradability of the test chemical which was described as below-Ultimate Biodegradation Timeframe and Primary Biodegradation Timeframe (Biowin 3 and 4)These two models estimate the time required for "complete" ultimate and primary biodegradation.  Primary biodegradation is the transformation of a parent compound to an initial metabolite.  Ultimate biodegradation is the transformation of a parent compound to carbon dioxide and water, mineral oxides of any other elements present in the test compound, and new cell material. Then the rating was given to each model, which indicates the time required to achieve ultimate and primary biodegradation in a typical or "evaluative" aquatic environment. The ratings for each compound were averaged to obtain a single value for modeling.  The ultimate or primary rating of a compound is calculated by summing, for all the fragments present in that compound.
Key result
Remarks on result:
other: not readily biodegradable as estimated by BIOWIN model
Details on results:
Biowin1 (Linear Model Prediction) : 0.8319: Biodegrades FastBiowin2 (Non-Linear Model Prediction): 0.8707: Biodegrades FastBiowin3 (Ultimate Biodegradation Timeframe): 3.0138: WeeksBiowin4 (Primary Biodegradation Timeframe): 3.7517: DaysBiowin5 (MITI Linear Model Prediction) : 0.4554: Does Not Biodegrade FastBiowin6 (MITI Non-Linear Model Prediction): 0.3314: Does Not Biodegrade FastBiowin7 (Anaerobic Model Prediction): 0.3226: Does Not Biodegrade FastReady Biodegradability Prediction: NO

BIOWIN (v4.10) Program Results:

==============================

SMILES : OC(C(CCC1C)C(C)C)C1

CHEM : Cyclohexanol, 5-methyl-2-(1-methylethyl)-, 1S-(1.alpha.,2.alpha.,5.b

eta.) -

MOL FOR: C10 H20 O1

MOL WT : 156.27

--------------------------- BIOWIN v4.10 Results ----------------------------

Biowin1 (Linear Model Prediction) : Biodegrades Fast

Biowin2 (Non-Linear Model Prediction): Biodegrades Fast

Biowin3 (Ultimate Biodegradation Timeframe): Weeks

Biowin4 (Primary Biodegradation Timeframe): Days

Biowin5 (MITI Linear Model Prediction) : Does Not Biodegrade Fast

Biowin6 (MITI Non-Linear Model Prediction): Does Not Biodegrade Fast

Biowin7 (Anaerobic Model Prediction): Does Not Biodegrade Fast

Ready Biodegradability Prediction: NO

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | Biowin1 FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Frag | 1 | Aliphatic alcohol [-OH] | 0.1587 | 0.1587

MolWt| * | Molecular Weight Parameter | | -0.0744

Const| * | Equation Constant | | 0.7475

============+============================================+=========+=========

RESULT | Biowin1 (Linear Biodeg Probability) | | 0.8319

============+============================================+=========+=========

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | Biowin2 FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Frag | 1 | Aliphatic alcohol [-OH] | 1.1178 | 1.1178

MolWt| * | Molecular Weight Parameter | | -2.2190

============+============================================+=========+=========

RESULT | Biowin2 (Non-Linear Biodeg Probability) | | 0.8707

============+============================================+=========+=========

A Probability Greater Than or Equal to 0.5 indicates --> Biodegrades Fast

A Probability Less Than 0.5 indicates --> Does NOT Biodegrade Fast

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | Biowin3 FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Frag | 1 | Aliphatic alcohol [-OH] | 0.1600 | 0.1600

MolWt| * | Molecular Weight Parameter | | -0.3453

Const| * | Equation Constant | | 3.1992

============+============================================+=========+=========

RESULT | Biowin3 (Survey Model - Ultimate Biodeg) | | 3.0138

============+============================================+=========+=========

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | Biowin4 FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Frag | 1 | Aliphatic alcohol [-OH] | 0.1294 | 0.1294

MolWt| * | Molecular Weight Parameter | | -0.2255

Const| * | Equation Constant | | 3.8477

============+============================================+=========+=========

RESULT | Biowin4 (Survey Model - Primary Biodeg) | | 3.7517

============+============================================+=========+=========

Result Classification: 5.00 -> hours 4.00 -> days 3.00 -> weeks

(Primary & Ultimate) 2.00 -> months 1.00 -> longer

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | Biowin5 FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Frag | 1 | Aliphatic alcohol [-OH] | 0.1611 | 0.1611

Frag | 3 | Methyl [-CH3] | 0.0004 | 0.0012

Frag | 1 | -CH- [linear] | -0.0507 | -0.0507

Frag | 3 | -CH2- [cyclic] | 0.0197 | 0.0592

Frag | 3 | -CH - [cyclic] | 0.0124 | 0.0373

MolWt| * | Molecular Weight Parameter | | -0.4649

Const| * | Equation Constant | | 0.7121

============+============================================+=========+=========

RESULT | Biowin5 (MITI Linear Biodeg Probability) | | 0.4554

============+============================================+=========+=========

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | Biowin6 FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Frag | 1 | Aliphatic alcohol [-OH] | 1.0041 | 1.0041

Frag | 3 | Methyl [-CH3] | 0.0194 | 0.0583

Frag | 1 | -CH- [linear] | -0.0998 | -0.0998

Frag | 3 | -CH2- [cyclic] | 0.2365 | 0.7096

Frag | 3 | -CH - [cyclic] | -0.1295 | -0.3884

MolWt| * | Molecular Weight Parameter | | -4.5113

============+============================================+=========+=========

RESULT |Biowin6 (MITI Non-Linear Biodeg Probability)| | 0.3314

============+============================================+=========+=========

A Probability Greater Than or Equal to 0.5 indicates --> Readily Degradable

A Probability Less Than 0.5 indicates --> NOT Readily Degradable

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | Biowin7 FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Frag | 1 | Aliphatic alcohol [-OH] | 0.1328 | 0.1328

Frag | 3 | Methyl [-CH3] | -0.0796 | -0.2387

Frag | 1 | -CH- [linear] | -0.1659 | -0.1659

Frag | 3 | -CH2- [cyclic] | -0.1200 | -0.3600

Frag | 3 | -CH - [cyclic] | 0.0395 | 0.1184

Const| * | Equation Constant | | 0.8361

============+============================================+=========+=========

RESULT | Biowin7 (Anaerobic Linear Biodeg Prob) | | 0.3226

============+============================================+=========+=========

A Probability Greater Than or Equal to 0.5 indicates --> Biodegrades Fast

A Probability Less Than 0.5 indicates --> Does NOT Biodegrade Fast

Ready Biodegradability Prediction: (YES or NO)

----------------------------------------------

Criteria for the YES or NO prediction: If the Biowin3 (ultimate survey

model) result is "weeks" or faster (i.e. "days", "days to weeks", or

"weeks" AND the Biowin5 (MITI linear model) probability is >= 0.5, then

the prediction is YES (readily biodegradable). If this condition is not

satisfied, the prediction is NO (not readily biodegradable). This method

is based on application of Bayesian analysis to ready biodegradation data

(see Help). Biowin5 and 6 also predict ready biodegradability, but for

degradation in the OECD301C test only; using data from the Chemicals

Evaluation and Research Institute Japan (CERIJ) database.

Validity criteria fulfilled:
not specified
Interpretation of results:
not readily biodegradable
Conclusions:
The biodegradability of the substance was calculated using seven different Biowin 1-7 models of the BIOWIN v4.10 software. The results indicate that the test chemical (+)-Neomenthol is expected to be not readily biodegradable.
Executive summary:

Estimation Programs Interface Suite (2018) was run to predict the biodegradation potential of the test compound  (+)-Neomenthol (CAS no. 2216 -52 -6) 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 chemical (+)-Neomenthol is expected to be not readily biodegradable.

Description of key information

Estimation Programs Interface Suite (2018) was run to predict the biodegradation potential of the test compound  (+)-Neomenthol (CAS no. 2216 -52 -6) 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 chemical (+)-Neomenthol is expected to be not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

Predicted data for the target compound (+)-Neomenthol (CAS No. 2216-52-6) and various supporting weight of evidence studies for its structurally and functionally similar read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction using the Estimation Programs Interface Suite (2018), the biodegradation potential of the test compound (+)-Neomenthol (CAS no. 2216 -52 -6) 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 (+)-Neomenthol is expected to be not readily biodegradable.

 

In a supporting weight of evidence study from peer reviewed journal (Harder et al, 1995),biodegradation experiment was conducted for 21 days for evaluating the percentage biodegradability of test substance by using Pseudomonas citronellolis DSM 50332 as an inoculum.Test inoculum Pseudomonas citronellolis DSM 50332 was obtained from the Deutsche Sammlung von Mikroorganismen, Braunschweig, Germany. Initial test substance conc. used for the study was 308.5 mg/l (2 mM). Anoxic media was used for the study. The medium contained (per liter of distilled water) 1 g of NaCl, 0.1 g of MgCl2.7H2O, 0.04 g of CaCl2, 0.5 g of KCl, 0.125 g of NH4Cl, 0.2 g of Na2SO4, 0.4 g of KH2PO4, 1.2 g of K2HPO4, and 0.85 g of NaNO3. After autoclaving, 2 ml of a non-chelated trace element mixture, 2 ml of a selenite-tungstate solution, vitamins, and 20 ml of a 1 M NaHCO3 solution were added, and the pH was adjusted to 7.0.Enrichment cultures were inoculated with activated sludge obtained from a local wastewater plant (Lintel, Osterholz-Scharmbeck, Germany). Enrichment cultures were maintained and test chemical consumption was measured in 21-ml glass tubes containing 15 ml of anoxic medium (10 mM nitrate, 0.5 ml 2,2,4,4,6,8,8-heptamethylnonane (HMN), and 2 mM test chemical). The overpressure due to gas formation was measured with a syringe, and 10 mM nitrate was added when the electron acceptor was depleted. The gas formed was analyzed by gas chromatography. Bacterial growth was observed daily and required between 3 - 22 days. Monoterpene contents were determined with a gas chromatograph equipped with flame ionization detectors and connected to a digital data-analyzing system. The amounts of monoterpene dissimilated were calculated from the differences in monoterpene contents between the pasteurized controls and the grown enrichment cultures. A model MAT ITS 40 ion trap system was used for the gas chromatography-mass spectrometry analysis. Microbial growth on test chemical was observed within 10 days to 3 weeks. The disappearance of test chemical in mud-free enrichment cultures was quantified. The percentage degradation of test substance was determined to be 1.13% degradation by Test mat. analysis parameter in 21 days. Thus, based on percentage degradation, test chemical is considered to be not readily biodegradable in nature.

 

Another biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance (HSDB, 2017). Activated sludge was used as a test inoculum for the study. The percentage degradation of test substance was determined to be 0% by BOD parameter in 28 days. Thus, based on percentage degradation, is considered to be not readily biodegradable in nature.

 

For the test chemical from authoritative database (J-CHECK and HSDB, 2017),biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance. The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I) under aerobic conditions. Activated sludge was used as a test inoculums for the study. 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 test substance was determined to be 0% and 5% by BOD, TOC removal and GC parameter in 28 days. Thus, based on percentage degradation, is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical (+)-Neomenthol (from modelling database, 2018), it can be concluded that the test substance (+)-Neomenthol can be expected to be not readily biodegradable in nature.