Sodium O-isobutyl dithiocarbonate

Distribution modelling

Administrative data

Endpoint:

distribution modelling

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Study period:

not applicable

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 adequate and reliable documentation / justification

Justification for type of information:

QSAR prediction:US EPA accepted QSAR method for organic chemicals properties assessment. Recognised method of fugacity calculations.

Data source

Reference

Reference Type:

other: QSAR

Title:

EPI Suite v 4.1/Level III Fugacity Model

Author:

US EPA

Year:

2014

Bibliographic source:

http://epa.gov/oppt/exposure/pubs/episuite.htm

Materials and methods

Model:

calculation according to Mackay, Level III

Calculation programme:

EPI Suite v 4.1/Level III Fugacity Model

Release year:

2 011

Media:

other: all

Test material

Test material information

Constituent 1

Reference substance name:

Sodium O-isobutyl dithiocarbonate

EC Number:

246-805-2

EC Name:

Sodium O-isobutyl dithiocarbonate

Cas Number:

25306-75-6

Molecular formula:

C5H10OS2.Na

IUPAC Name:

sodium [(2-methylpropoxy)methanethioyl]sulfanide

Test material form:

solid: bulk

Details on test material:

SIBX/Sodium O-isobutyl dithiocarbonate is produced by the reaction of an isobutyl alcohol with sodium hydroxide to form alcoholate and subsequently adding carbon disulfide to form SIBX/ Sodium O-isobutyl dithiocarbonate.
SIBX/Sodium O-isobutyl dithiocarbonate contains 2-methylpropan-1-ol l/isobutyl alcohol (CAS number 78-83-1) and sodium hydroxide (CAS number 1310-73-2) which are an integral part of the substance.

2-methylpropan-1-ol l/ isobutyl alcohol (CAS number 78-83-1) and sodium hydroxide (CAS number 1310-73-2) are both reagents used in the manufacture of SIBX/Sodium O-isobutyl dithiocarbonate. Therefore, 2-methylpropan-1-ol l/ isobutyl alcohol (CAS number 78-83-1) and sodium hydroxide (CAS number 1310-73-2) need to be considered in the assessment of SIBX/Sodium O-isobutyl dithiocarbonate.

CAS name: isobutyl alcohol
EC / List name: 2-methylpropan-1-ol
IUPAC name: 2-methylpropan-1-ol
EC / List no.: 201-148-0
CAS no.: 78-83-1

CAS name: sodium hydroxide
EC / List name: Sodium hydroxide
IUPAC name: sodium hydroxide
EC / List no.: 215-185-5
CAS no.: 1310-73-2

Study design

Test substance input data:

- Parameters as per physicochemical summary data.
- Reaction half-life estimates for:
- Air: 16 hr (from AOPWIN)
- Water: 360 hr (Based on Biowin)
- Soil: 720 hr
- Sediment: 3240 hr

Assumed emissions: Four simulations as per results below

Environmental properties:

- Environmental compartment sizes and character as per the TGD

Results and discussion

Percent distribution in media

Air (%):

0

Water (%):

29.7

Soil (%):

70.2

Sediment (%):

0.069

Susp. sediment (%):

0

Biota (%):

0

Aerosol (%):

0

Other distribution results:

The figures above represent the first emission scenario shown below

Any other information on results incl. tables

 

   

Level III Fugacity Model (Full-Output):

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

Chem Name : Carbonodithioic acid, o-(2-methylpropyl) ester, sodium salt

Molecular Wt: 172.24

Henry's LC : 3.49e-016 atm-m3/mole (calc VP/Wsol)

Vapor Press : 1.26e-009 mm Hg (Mpbpwin program)

Liquid VP : 7.19e-008 mm Hg (super-cooled)

Melting Pt : 203 deg C (Mpbpwin program)

Log Kow : -1.33 (Kowwin program)

Soil Koc : 11.7 (KOCWIN MCI method)

 

TABLE 1

	Mass Amount (percent)	Half-Life (hr)	Emissions   (kg/hr)
Air	9.95e-008	16	1000
Water	29.7	360	1000
Soil	70.2	720	1000
Sediment	0.069	3.24e+003	0

 

TABLE 2A

	Fugacity atm)	Reaction (kg/hr)	Advection (kg/hr)	Reaction (percent)	Advection (percent)
Air	2.03e-019	8.36e-005	1.93e-005	2.79e-006	6.44e-007
Water	5.84e-021	1.11e+003	577	37	19.2
Soil	2.64e-019	1.31e+003	0	43.8	0
Sediment	5.3e-021	0.287	0.0268	0.00955	0.000893

 

 

Persistence Time: 647 hr

Reaction Time: 801 hr

Advection Time: 3.37e+003 hr

Percent Reacted: 80.8

Percent Advected: 19.2

 

Half-Lives (hr), (based upon Biowin (Ultimate) and Aopwin):

Air: 16.01

Water: 360

Soil: 720

Sediment: 3240

Biowin estimate: 2.819 (weeks )

Advection Times (hr):

Air: 100

Water: 1000

Sediment: 5e+004

 

Applicant's summary and conclusion

Conclusions:

SIBX has no affinity to be in air and sediment. The direct emissions to soil and surface water are significant, therefore Reaction mass of SIBX will be almost exclusively be found in soil and surface water.

Executive summary:

Mackay fugacity modelling (level 3) indicates that, taking into account degradation and using inflow parameters which are consistent with the known production tonnage of this substance in, fugacity coefficient indicates that environmental concentrations in water are predicted to be 5.84e-021 (atm), in air (atm) 2.03e-019and soil 2.64e-019 (atm) and sediment to be  5.3e-021  (atm).

These are negligible low levels. This can be considered a worse case prediction as it assumes all product is emitted with no emission control systems used.