Sodium O-isobutyl dithiocarbonate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

July 08, 2021 - September 28, 2021

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Sodium isobutyl xanthate (Sodium O-isobutyl dithiocarbonate);
batch no.: MK/01/04/2021, the content of sodium O-isobutyl
dithiocarbonate: 94.0 ±1%; manufacturing date: April 15,
2021, expiry date: April 15, 2022.

Analytical monitoring:

not specified

Details on sampling:

Qualitative analysis was not considered possible due to method limitations.
Total Organic Carbon analysis was performed to confirm dosing concentrations based on dissolve carbon.
It is likely that the substance rapidly hydrolysed leading to failure in analysis.

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia magna Straus (< 24 h old at exposure initiation); not
first brood progeny; neonates collected from a laboratory culture cultivated at the Łukasiewicz Research Network – Institute of Industrial Organic Chemistry Branch Pszczyna.

Test type:

static

Water media type:

freshwater

Total exposure duration:

48 h

Test temperature:

20.1-21.2 oC

pH:

7.85-7.99

Dissolved oxygen:

9.2-9.8 mg/L

Nominal and measured concentrations:

15, 7.5, 3.8, 1.88, 0.94 mg/L plus the control.

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

7.24 mg/L

95% CI:

> 5.99 - < 8.77

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

38 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

7.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Validity criteria fulfilled:

yes

Executive summary:

Immobilisation of Daphnia magna exposed to the test item, Sodium isobutyl xanthate
(Sodium O-isobutyl dithiocarbonate) was investigated during a 48-hour static test. The
test was performed in glass beakers of 150 mL capacity, containing 100 mL of either the
test item concentration or the control per replicate. The definitive test was performed with
the test item concentrations of 15, 7.5, 3.8, 1.88, 0.94 mg/L plus the control.
The Daphnia magna were observed for immobilisation after 24 and 48 h of exposure. The
Daphnia magna were considered immobile if they showed no ability to swim within
15 seconds after gentle swirling of the test vessel.
At exposure termination in the test item concentrations of 15, 7.5, 3.8, 1.88, 0.94 mg/L
and the control, the immobilisation of Daphnia magna was 90, 70, 0, 0, 0 and 0%,
respectively. No abnormal behaviour of Daphnia magna was observed during exposure.
The total organic carbon analyses were performed in fresh samples of all test item
concentrations and the control at exposure initiation and in old samples of all test item
concentrations and the control at exposure termination (48-h old). This analytical approach
did not account for any degradation or metabolisation effects which may have occurred
during exposure. The results were corrected by the value determined for the control sample
in a series and presented as the concentrations of total organic carbon (TOC).
In samples collected at exposure initiation, the analysed total organic carbon
concentrations were in the range of below the LoQ value (< 1.0 mg C/L) – 12.8 mg C/L.
In 48-h old samples collected at exposure termination, the analysed total organic carbon
concentrations were in the range of below the LoQ value (< 1.0 mg C/L) – 12.6 mg C/L.
The endpoint values were determined based on the nominal test item concentrations.

 

Description of key information

A number of studies have been performed on the group of xanthates giving similar results 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

7.24 mg/L

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

0.56 mg/L