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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Reference
Endpoint:
biodegradation in water: sediment simulation testing
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
Qualifier:
according to
Guideline:
other: Modeling database
Principles of method if other than guideline:
Fugacity Model by EPI Suite estimation database
GLP compliance:
not specified
Specific details on test material used for the study:
- Name of test material : Ethyl butyrate
- Molecular formula: C6H12O2
- Molecular weight: 116.1588 g/mol
- SMILES: C(=O)(CCC)OCC
- InChI: 1S/C6H12O2/c1-3-5-6(7)8-4-2/h3-5H2,1-2H3
- Substance type: Organic
- Physical state: Liquid
Radiolabelling:
not specified
Oxygen conditions:
other: estimation
Inoculum or test system:
not specified
Parameter followed for biodegradation estimation:
test mat. analysis
Details on study design:
Level III Fugacity model
EPI Suite contains a Level III fugacity model. In general, fugacity models predict the partitioning of an organic compound in an evaluative environment. A Level III model assumes steady-state but not equilibrium conditions. The Level III model in EPI Suite predicts partitioning between air, soil, sediment and water using a combination of default parameters and various input parameters that may be user defined or estimated by other programs within EPI Suite.

The model environment consists of 4 main compartments: air, water sediment and soil. There are also sub-compartments such as an aerosol phase, suspended solids, and biota phase, within specific main compartments. A fixed temperature of 25ᵒC is assumed. Mass transport between the compartments via volatilization, diffusion, deposition and runoff are modeled. level III models is a steady state, non-equilibrium model. Steady state conditions mean that the change in concentration of a chemical in each compartment (i) with respect to time eventually approaches zero. The model does not assume that a common equilibrium (fugacity) exists between the phases, so if a chemical is emitted into one compartment it can partition to the other compartments. Loss of chemical occurs through two processes: reaction and advection. Reaction is the biotic or abiotic degradation of the chemical that is calculated using the user specified or model calculated half-lives of the chemical in each of the 4 main compartments. Advection processes are considered for the air, water and sediment compartments. Advection is the removal of chemical from a compartment through losses other than degradation (reaction). The rate of advection in a given compartment is determined by a flow rate (m3/hour), calculated by dividing the volume of the compartment by an advection time.
Compartment:
water
% Recovery:
39.8
Remarks on result:
other: Other details not known
Compartment:
sediment
% Recovery:
0.105
Remarks on result:
other: Other details not known
Key result
% Degr.:
50
Parameter:
other: Half-life in water
Sampling time:
15 d
Remarks on result:
other: Other details not known
Key result
% Degr.:
50
Parameter:
other: Half-life in sediment
Sampling time:
135 d
Remarks on result:
other: Other details not known
Key result
Compartment:
water
DT50:
15 d
Type:
other: estimated data
Temp.:
25 °C
Remarks on result:
other: Other details not known
Key result
Compartment:
sediment
DT50:
135 d
Type:
other: estimated data
Temp.:
25 °C
Remarks on result:
other: Other details not known
Transformation products:
not specified
Evaporation of parent compound:
not specified
Volatile metabolites:
not specified
Residues:
not specified

Mass Amount

(percent)

Half-Life (hr)

Emissions (kg/hr)

Water

39.8

360

1000

Sediment

0.105

3.24e+003

0

 

Fugacity (atm)

Reaction (kg/hr)

Advection (kg/hr)

Reaction (percent)

Advection (percent)

Water

4.26e-009

477

248

15.9

8.27

Sediment

3.84e-009

0.14

0.0131

0.00468

0.000437

Validity criteria fulfilled:
not specified
Conclusions:
Estimated half life of test chemical in water was 15 days (360h) and in sediment estimated to be 135 days (3240 h).
Executive summary:

Estimation Programs Interface (2018) prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 39.8% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 15 days (360 hrs). The half-life (15 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 test chemical in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.105%), indicates that test chemical is not persistent in sediment.

 

Description of key information

Estimation Programs Interface (2018) prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 39.8% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 15 days (360 hrs). The half-life (15 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 test chemical in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.105%), indicates that test chemical is not persistent in sediment.

 

Key value for chemical safety assessment

Half-life in freshwater:
15 d
at the temperature of:
25 °C
Half-life in freshwater sediment:
135 d
at the temperature of:
25 °C

Additional information

Estimation Programs Interface (2018) prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 39.8% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 15 days (360 hrs). The half-life (15 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 test chemical in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.105%), indicates that test chemical is not persistent in sediment.