Tetrasodium 4-amino-6-[[2,5-dimethoxy-4-[[2-(sulphonatooxy)ethyl]sulphonyl]phenyl]azo]-5-hydroxy-3-[[4-[[2-(sulphonatooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2,7-disulphonate

Distribution modelling

Administrative data

Endpoint:

distribution modelling

Type of information:

calculation (if not (Q)SAR)

Remarks:

Migrated phrase: estimated by calculation

Adequacy of study:

key study

Study period:

Not applicable

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The level III fugacity modelling of EPIWEB v 4.10 was used which is a direct adaption of the methodology of Mackay’s EQC model, which is a well established and validated distribution model.

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

other: software

Title:

Level III Fugacity model (EPIWEB v 4.10)

Author:

U.S. Environmental Protection Agency

Year:

2015

Bibliographic source:

Estimation Programs Interface Suite™ for Microsoft® Windows, v 4.10. United States Environmental Protection Agency, Washington, DC, USA.

Materials and methods

Model:

calculation according to Mackay, Level III

Calculation programme:

Mackay Level III Fugacity model (EPIWEB v 4.10)

Release year:

2 015

Media:

other: air-water-sediment-soil

Test material

Test material information

Constituent 1

Reference substance name:

Reactive Blue 203

IUPAC Name:

Reactive Blue 203

Study design

Test substance input data:

Environmental parameters: All half-lifes (in air, water, soil and sediment), emissions, soil Koc and advection values derived by estimation methods within EPI Suite are used as the input environmental parameters. Other physchem parameters used for estimation are melting point, vapor pressure, Henry’s Law constant and log Kow.

Results and discussion

Percent distribution in media

Air (%):

0

Water (%):

3.18

Soil (%):

86.5

Sediment (%):

10.3

Other distribution results:

None

Any other information on results incl. tables

Table: Partitioning model

Compartment	Distribution [%]	Half-life [h]
Air	2.31E-6	10.3
Water	3.18	4.32E3
Soil	86.5	8.64E3
Sediment	10.3	3.89E4

Applicant's summary and conclusion

Conclusions:

Results indicate that the substance is more likely to distribute to water.

Executive summary:

A Level III fugacity model was conducted in the US EPA EPISUITE which 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. This model has been used to calculate the theoretical distribution of the highest % component substance between four environmental compartments (air, water, soil, sediment) at steady state in a unit world.

It is proposed that although the majority of the substance distributes to the soil and sediment compartments (86.5 and 10.3% respectively) within the model, the high solubility in water indicates that the substance is more likely to distribute to water – e. g. soil pore water.

This assumption is confirmed by the model for the STP Overall Chemical Mass Balance in the US EPA EPI SUITE, which shows that 98% of the influent of the dye is in the water phase.