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Link to relevant study record(s)

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
Reference:
Composition 0
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
Test material information:
Composition 1
Specific details on test material used for the study:
- Name of test material (IUPAC name): 2-(3-oxobenzo[b]thien-2(3H)-ylidene)benzo[b]thiophene-3(2H)-one
- Molecular formula: C16H8O2S2
- Molecular weight: 296.369 g/mol
- Smiles : O=C1c2c(S\C1=C1/Sc3c(cccc3)C1=O)cccc2
- InChI : 1S/C16H8O2S2/c17-13-9-5-1-3-7-11(9)19-15(13)16-14(18)10-6-2-4-8-12(10)20-16/h1-8H/b16-15-
- Substance Type: Organic
- Physical State: Solid
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:
11.2
Remarks on result:
other: Other details not known
Compartment:
sediment
% Recovery:
1.71
Remarks on result:
other: Other details not known
Key result
% Degr.:
50
Parameter:
other: Half-life in water
Sampling time:
37.5 d
Remarks on result:
other: Other details not known
Key result
% Degr.:
50
Parameter:
other: Half-life in sediment
Sampling time:
337.5 d
Remarks on result:
other: Other details not known
Key result
Compartment:
water
Half-life:
37.5 d
Type:
other: estimated data
Temp.:
25 °C
Remarks on result:
other: Other details not known
Key result
Compartment:
sediment
Half-life:
337.5 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

11.2

900

1000

Sediment

1.71

8.1e+003

0

 

Fugacity (atm)

Reaction (kg/hr)

Advection (kg/hr)

Reaction (percent)

Advection (percent)

Water

4.8e-018

482

626

16.1

20.9

Sediment

5.64e-018

8.16

1.91

0.272

0.0636

Validity criteria fulfilled:
not specified
Conclusions:
Estimated half life of test chemical in water was 37.5 days (900 h) and in sediment estimated to be 337.5 days (8100 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, 11.2% 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 37.5 days (900 hrs). The half-life (37.5 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 337.5 days (8100 hrs). However, as the percentage release of test chemical into the sediment is less than 2% (i.e, reported as 1.71%), 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, 11.2% 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 37.5 days (900 hrs). The half-life (37.5 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 337.5 days (8100 hrs). However, as the percentage release of test chemical into the sediment is less than 2% (i.e, reported as 1.71%), indicates that test chemical is not persistent in sediment.

Key value for chemical safety assessment

Half-life in water:
37.5 d
at the temperature of:
25 °C
Half-life in sediment:
337.5 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, 11.2% 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 37.5 days (900 hrs). The half-life (37.5 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 337.5 days (8100 hrs). However, as the percentage release of test chemical into the sediment is less than 2% (i.e, reported as 1.71%), indicates that test chemical is not persistent in sediment.