Registration Dossier

Administrative data

Endpoint:
distribution modelling
Type of information:
(Q)SAR
Remarks:
Migrated phrase: estimated by calculation
Adequacy of study:
key study
Study period:
April 2010
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Estimated performed using software recommended by REACH Guidance.

Data source

Reference
Reference Type:
other: software program
Title:
EPI v3.20. (February 2007. Estimation Programs Interface. U.S. Environmental Protection Agency Office of Pollution Prevention and Toxic Substances. Syracuse Research Corporation).
Author:
anonymous
Year:
2007
Bibliographic source:
U.S. Environmental Protection Agency, Washington, D.C.

Materials and methods

Model:
calculation according to Mackay, Level III
Calculation programme:
Level III Fugacity Model, EPIwin v3.20
Release year:
2 007
Media:
other: air, water, soil, sediment

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Modeled on DBDPEthane's chemical structure

Study design

Test substance input data:
Chemical structure was input into EPI.
Environmental properties:
Default model parameters

Results and discussion

Percent distribution in media

Air (%):
0.05
Water (%):
0.6
Soil (%):
48.8
Sediment (%):
50.5
Aerosol (%):
0

Any other information on results incl. tables

Predicted Transport and Distribution Between Environmental Compartments

DBDPEthane’s transport and distribution between environmental compartments was modeled using EPI v. 3.20, and based on the chemical’s structure. In the environment, 99.3% of DBDPEthane's releases are predicted to distribute to sediment and soil. DBDPEthane is predicted to partition to sediment (50.5%) and soil (48.8%) with negligible amounts partitioning to water (0.6%) and air (0.05%) (Level III Fugacity Model; Emissions of 1000 kg/hr to each of air, water, soil).  It is expected to bind extensively to organic carbon based on estimated Koc values (Table), and therefore to be essentially immobile in soil, sewage sludge, and sediments. It is not expected to volatilize from water (Volatilization half-life in rivers = 7 years, in lakes = 77 years). In air, it is expected to bind to airborne particulates. The fraction sorbed to particulates is estimated to be 1 at 25°C (AEROWIN v1.00). Its characteristic travel distance is expected to be low, which indicates it should not be subject to long-range transport in the atmosphere. Its movement in the atmosphere will be governed by that of the particulates to which it is bound.

Removal in sewage treatment plants is expected (94% total removal) through settling in sludge (60% in primary sludge, 33% in waste sludge) (STP Fugacity Model). Aerobic biodegradation in a sewage treatment plants is not expected. The amount in the final water effluent leaving a treatment plant is estimated at approximately 6% of the influent. 

Estimated Properties for DBDPEthane using EPI (v3.20).

Property

Result

EPI Module

Henry’s Law Constant (25ºC)

6.42 x 10-8atm-m3/mole (Bond)

2.94 x 10-8atm-m3/mole (Group)

HENRY (v3.10)

2.94 x 10-8atm-m3/mole

1.20 x 10-6unitless

HENRYWIN v3.10

2.09 x 10-1atm-m3/mole

VP/Wsol Estimate using EPI values

Liquid/Subcooled Vapor Pressure

9.33 x 10-9Pa

7 x 10-11Hg

AEROWIN v1.00

Log Koa (octanol/air partition coefficient)

19.221

KOAWIN v1.10

Log Kaw (air/water partition coefficient)

-5.581

KOAWIN v1.10

Particle/gas Partition Coefficient (Kp) (m3/μg)

321 (Mackay model)

4.08 x106(Koa model)

AEROWIN v1.00

Reaction with Hydroxyl Radicals in the Atmosphere

Overall OH Rate Constant = 2.395 x10-12cm3/molecule-sec;

Half-life = 4.466 days (12-hr d; 1.5x106OH/cm3)

AOP v1.92

Koc

3.312 x 106

PCKOC (v1.66)

Biomass to water partition coefficient

8.73 x 1012

STP Fugacity Model

Applicant's summary and conclusion

Conclusions:
DBDPE is expected to partition in the environment to sediment and soil (ca. 99%). High binding to particulates in all media is expected. Sewage treatment plants are expected to remove > 95% of that present in the influent. Removal is expected to be via binding to particulates rather than biodegradation. Its characteristic travel distance is expected to be low and long range atmospheric transport is not expected. Its movement in the atmosphere will be governed by the particulates to which it is bound.
Executive summary:

DBDPE is expected to parition in the environment to sediment and soil (ca. 99%). High binding to particulates in all media is expected. Sewage treatment plants are expected to remove > 95% of that present in the influent. Removal is expected to be via binding to particulates rather than biodegradation. Its characteristic travel distance is expected to be low and long range atmospheric transport is not expected. Its movement in the atmosphere will be governed by the particulates to which it is bound.