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Environmental fate & pathways

Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: ready biodegradability
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This read-across is based on the hypothesis that source and target substances have similar toxicological properties because
• they are manufactured from similar or identical precursors under similar conditions
• they share structural similarities with common functional groups: methacrylate esters
• the metabolism pathway leads to comparable products (methacrylic acid and short chain alcohol).

Therefore, read-across from the existing (eco)toxicity studies on the source substances is considered as an appropriate adaptation to the standard information requirements of REACH regulation

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
see crossreference “Justification for read-across”

3. ANALOGUE APPROACH JUSTIFICATION
see crossreference “Justification for read-across”

4. DATA MATRIX
see crossreference “Justification for read-across”
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across source
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Parameter:
other: BOD
Value:
>= 92 - <= 100
Sampling time:
14 d
Parameter:
% degradation (TOC removal)
Value:
>= 86 - <= 87
Sampling time:
14 d
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The test substance was degraded 92-100% after 14 days.
Endpoint:
biodegradation in water: screening tests
Type of information:
(Q)SAR
Adequacy of study:
supporting study
Study period:
2013
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
Qualifier:
no guideline followed
Principles of method if other than guideline:
estimated by calculation using EPIWEB version 4.1, BIOWIN (v4.10)
GLP compliance:
no

BIOWIN (v4.10) Program Results:

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

SMILES : O=C(OCCOC)C(=C)C

CHEM  : MTMA

MOL FOR: C7 H12 O3

MOL WT : 144.17

--------------------------- 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)   : Biodegrades Fast

Biowin6 (MITI Non-Linear Model Prediction): Biodegrades Fast

Biowin7 (Anaerobic Model Prediction): Does Not Biodegrade Fast

Ready Biodegradability Prediction: YES

 

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

TYPE | NUM |      Biowin1 FRAGMENT DESCRIPTION        | COEFF | VALUE

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

Frag | 1 | Ester  [-C(=O)-O-C]                     | 0.1742 | 0.1742

Frag | 1 | Aliphatic ether [C-O-C]                 | -0.3474 | -0.3474

MolWt| * | Molecular Weight Parameter               |        | -0.0686

Const| * | Equation Constant                        |        | 0.7475

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

RESULT  |   Biowin1 (Linear Biodeg Probability)    |        | 0.5057

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

 

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

TYPE | NUM |      Biowin2 FRAGMENT DESCRIPTION        | COEFF | VALUE

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

Frag | 1 | Ester  [-C(=O)-O-C]                     | 4.0795 | 4.0795

Frag | 1 | Aliphatic ether [C-O-C]                 | -3.4294 | -3.4294

MolWt| * | Molecular Weight Parameter               |        | -2.0472

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

RESULT  | Biowin2 (Non-Linear Biodeg Probability)  |        | 0.8336

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

 

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 | Ester  [-C(=O)-O-C]                     | 0.1402 | 0.1402

Frag | 1 | Aliphatic ether [C-O-C]                 | -0.0087 | -0.0087

MolWt| * | Molecular Weight Parameter               |        | -0.3186

Const| * | Equation Constant                        |        | 3.1992

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

RESULT  | Biowin3 (Survey Model - Ultimate Biodeg) |        | 3.0121

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

 

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

TYPE | NUM |      Biowin4 FRAGMENT DESCRIPTION        | COEFF | VALUE

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

Frag | 1 | Ester  [-C(=O)-O-C]                     | 0.2290 | 0.2290

Frag | 1 | Aliphatic ether [C-O-C]                 | -0.0097 | -0.0097

MolWt| * | Molecular Weight Parameter               |        | -0.2080

Const| * | Equation Constant                        |        | 3.8477

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

RESULT  |  Biowin4 (Survey Model - Primary Biodeg) |        | 3.8590

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

 

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 | Ester  [-C(=O)-O-C]                     | 0.3437 | 0.3437

Frag | 1 | Aliphatic ether [C-O-C]                 | 0.0015 | 0.0015

Frag | 2 | Methyl [-CH3]                           | 0.0004 | 0.0008

Frag | 2 | -CH2- [linear]                          | 0.0494 | 0.0988

Frag | 2 | -C=CH [alkenyl hydrogen]                | 0.0062 | 0.0124

MolWt| * | Molecular Weight Parameter               |        | -0.4289

Const| * | Equation Constant                        |        | 0.7121

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

RESULT  | Biowin5 (MITI Linear Biodeg Probability) |        | 0.7405

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

 

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

TYPE | NUM |      Biowin6 FRAGMENT DESCRIPTION        | COEFF | VALUE

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

Frag | 1 | Ester  [-C(=O)-O-C]                     | 2.4462 | 2.4462

Frag | 1 | Aliphatic ether [C-O-C]                 | -0.1071 | -0.1071

Frag | 2 | Methyl [-CH3]                           | 0.0194 | 0.0389

Frag | 2 | -CH2- [linear]                          | 0.4295 | 0.8590

Frag | 2 | -C=CH [alkenyl hydrogen]                | 0.0285 | 0.0570

MolWt| * | Molecular Weight Parameter               |        | -4.1621

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

RESULT  |Biowin6 (MITI Non-Linear Biodeg Probability)|        | 0.8399

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

 

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 | Ester  [-C(=O)-O-C]                     | 0.1719 | 0.1719

Frag | 1 | Aliphatic ether [C-O-C]                 | -0.2573 | -0.2573

Frag | 2 | Methyl [-CH3]                           | -0.0796 | -0.1591

Frag | 2 | -CH2- [linear]                          | 0.0260 | 0.0520

Frag | 2 | -C=CH [alkenyl hydrogen]                | -0.0735 | -0.1470

Const| * | Equation Constant                        |        | 0.8361

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

RESULT  |  Biowin7 (Anaerobic Linear Biodeg Prob)  |        | 0.4965

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

 

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. 

 

Interpretation of results:
readily biodegradable
Conclusions:
Based on the prediction of EPIWEB version 4.1, BIOWIN (v4.10) MTMA is considered to be readily biodegradable.

Description of key information

readily biodegradable

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information

No reliable experimental data are available for the biodegradation of MTMA.

Reliable studies are available for the structurally realted HEMA: In a MITI, OECD 301C biodegradation test, HEMA was found to be readily biodegradable based on 92 -100% degradation after 14 days.

Thus, by read-across and based upon EPIWEB predictions (EPIWEB version 4.1, BIOWIN (v4.10)) and structural considerations MTMA is considered readily biodegradable.