Sodium O-isobutyl dithiocarbonate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

other: published data

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

Carbon disulphide is both a reagent in the manufacture, as well as a decomposition product of xanthates. SIBX readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the health effects of carbon disulphide (CS2) need to be considered in the assessment of SIBX.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Analytical monitoring:

not specified

Vehicle:

no

Test organisms (species):

Chlorella pyrenoidosa

Details on test organisms:

SPECIES #
(NAME): 426 Chlorella pyrenoidosa (Green Algae)
AGE: NR NR
LIFE STAGE: not reported, unknown
COMMENT: 10E+8 CELLS/100 ML

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

90 mg CaCO3/L

Test temperature:

20 ± 1 °C

pH:

8.7 ± 0.2

Dissolved oxygen:

NR

Salinity:

NR

Details on test conditions:

The test was carried out in sealed flasks to prevent evaporation of CS2.
The medium contained major salts, urea, Ca-glycerophosphate, dextrose and trace elements. The complete composition of the test medium is given in Van Leeuwen and Maas, Environ. Pollution A37: 105-115 (1985).
The starting density of the cells was 1E5 cells/mL. The volume of test medium was 100 mL per flask. The medium was shaken under fluorescent light (7.5 W/m2).

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

21 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

47.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: On a molecular weight scaled basis, the EC50 would be 47.5 mg/l. (21 x 172.24) /76.13 =47.5 mg/l

Details on results:

Carbon disulphide is both a reagent in the manufacture, as well as a decomposition product of xanthates. Reaction mass of SIBX readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the health effects of carbon disulphide (CS2) need to be considered in the assessment of Reaction mass of SIBX.
On a molecular weight scaled basis, the EC50 would be 47.5 mg/l.
(21 x 172.24) /76.13 =47.5 mg/l

Reported statistics and error estimates:

no data

Validity criteria fulfilled:

yes

Conclusions:

The 96-h EC50 of CS2 for the alga Chlorella pyrenoidosa in sealed flasks was 21 mg/L, based on the inhibition of growth rate.
Carbon disulphide is both a reagent in the manufacture, as well as a decomposition product of xanthates. SIBX readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the health effects of carbon disulphide (CS2) need to be considered in the assessment of SIBX.
On a molecular weight scaled basis, the EC50 would be 47.5 mg/l. (21 x 172.24) /76.13 =47.5 mg/l

Executive summary:

Carbon disulphide is both a reagent in the manufacture, as well as a decomposition product of xanthates. Reaction mass of SIBX readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the health effects of carbon disulphide (CS2) need to be considered in the assessment of Reaction mass of SIBX. On a molecular weight scaled basis, the EC50 would be 47.5 mg/l. (21 x 172.24) /76.13 =47.5 mg/l

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

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 chemicals properties assessment.

Qualifier:

according to guideline

Guideline:

other: QSAR model

Principles of method if other than guideline:

ECOSAR Program(v1.00)

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

other: QSAR model

Details on test organisms:

not applicable. QSAR model

Test type:

other: QSAR model

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

not applicable. QSAR model

pH:

not applicable. QSAR model

Dissolved oxygen:

not applicable. QSAR model

Salinity:

not applicable. QSAR model

Nominal and measured concentrations:

not applicable. QSAR model

Details on test conditions:

100% sodium O-isobutyl dithiocarbonate
SMILES : O(C(CC)C)C(S([Na]))=S
CHEM : Carbonodithioic acid, o-(2-methylpropyl) ester, sodium salt
CAS Num: 25306-75-6
MOL FOR: C5 H9 O1 S2 Na1
MOL WT : 172.24
Log Kow: 1.78 (used)
Wat Sol: 663 mg/L (measured)

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

48.819 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

not specified

Duration:

30 d

Dose descriptor:

NOEC

Effect conc.:

17.983 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

not specified

Remarks on result:

other: NOEC cited as a ChV value

Details on results:

Green Algae, 96-hr EC50 = 48.819mg/L (ppm)
Green Algae, 30-day, NOEC cited as a ChV value = 17.983 mg/L(ppm)

Overview of QSARs estimations on aquatic toxicity of  SIBX to Green algae

Method	Results	Remarks	Reference
QSAR estimate	Green Algae,96-hr EC50 = 48.819 mg/L (ppm)   Green Algae, 30-day, ChV (chronic value) =17.983 mg/L(ppm)	Reliable with restrictions, QSAR estimated data	ECOSAR Program (v1.00)

 

Green Algae, 96-hr EC50 = 48.819mg/L (ppm)

Green Algae, 30-day, NOEC cited as a ChV value = 17.983 mg/L(ppm)

Validity criteria fulfilled:

yes

Remarks:

method for chemicals properties assessment.

Conclusions:

Green Algae, 96-hr EC50 = 48.819 mg/L (ppm)
Green Algae, 30-day, NOEC cited as a ChV value = 17.983 mg/L(ppm)

Executive summary:

The ECOSAR QSAR model predicts that 30-day, NOEC cited as a ChV value would to be 17.983 mg/L (ppm) Green Algae.

The ECOSAR QSAR model predicts that 96-hr EC50 value would to be 48.819 mg/L (ppm) for Green Algae.

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

2-methylpropan-1-ol /Isobutyl alcohol/ is both reagents used in the manufacture of sodium O-isobutyl dithiocarbonate . Therefore, 2-methylpropan-1-ol /Isobutyl alcohol/ need to be considered in the assessment of sodium O-isobutyl dithiocarbonate

Qualifier:

according to guideline

Guideline:

other: DIN 38412, Part 9

Principles of method if other than guideline:

Cell multiplication inhibition test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Scenedesmus suspicatus (SAG 8681)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

NR

Test temperature:

24 0C

pH:

8.0 to 9.3

Dissolved oxygen:

NR

Salinity:

NR

Nominal and measured concentrations:

Concentration range: 80-10000 mg/L

Details on test conditions:

Extinction was measured at 578nm

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

230 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1 250 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

A 48h EC50 of 230 mg/L has been determined for the effects of the test substance (Isobutyl Alcohol ) on growth rate of the
Scenedesmus suspicatus
Isobutyl Alcohol is both reagents used in the manufacture, as well as decomposition products of xanthates.

Validity criteria fulfilled:

yes

Conclusions:

A 48h EC50 of 230 mg/L has been determined for the effects of the test substance (Isobutyl Alcohol ) on growth rate of the
Scenedesmus suspicatus
Isobutyl Alcohol is both reagents used in the manufacture, as well as decomposition products of xanthates.

Description of key information

The ECOSAR QSAR model predicts that 30-day, NOEC cited as a ChV value would to be 17.983 mg/L (ppm) Green Algae.
The ECOSAR QSAR model predicts that 96-hr EC50 value would to be 48.819 mg/L (ppm) for Green Algae.

Key value for chemical safety assessment

EC50 for freshwater algae:

48.819 mg/L

EC50 for marine water algae:

4.88 mg/L

EC10 or NOEC for freshwater algae:

17.983 mg/L

EC10 or NOEC for marine water algae:

1.8 mg/L

Additional information

The ECOSAR QSAR model predicts that 30-day, NOEC cited as a ChV value would to be 17.983mg/L (ppm) Green Algae.

The ECOSAR QSAR model predicts that 96-hr EC50 value would to be 48.819mg/L (ppm) forGreen Algae.

The available data for saltwater algae and cyanobacteria are limited and to obtaine the value for PNECs for saltwaters is taken account a assesment factor 10 to extrapolate to LC50 following the “Guidance on Information Requirement and Chemical Safety Assessment R.10: Characterisation of dose [concentration]- response for environment”and “Table R.10-5 Assessment factors proposed for deriving PNEC water for saltwater for different data sets”, to account for the possibility that greater taxonomic diversity in the marine environment makes it likely that some marine taxa may be more sensitive than the most sensitive freshwater taxa