Sodium O-ethyl dithiocarbonate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

other: published data

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

The SEX , the subject of this dossier) is expected to exhibit very similar toxicity to Potassium isobutyl xanthate (CAS No.13001-46-2), which is also xanthate compound. Comparable metabolism would occur.

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, adapted

Details on inoculum:

The inoculum used was activated sludge from a semi-continuous colony maintained in the laboratory.
Incubation was carried out at 25°C in 200 ml Erlenmeyer flasks containing 5 ul of a alcohol and 100 ml of culture medium.
Biodegradation rate constant was determined by measurement ofthe alcohol concentration in the supernatant of the culture
by gas chromatography.

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

test mat.

Reference substance:

not specified

Value:

98

Sampling time:

12 d

Value:

30

Sampling time:

3 h

Value:

75

Sampling time:

5 d

Details on results:

The IUCLID datasheet describes an aerobic biodegradation test for potassium isobutyl xanthate following the OECD Guide-line 302B “Inherent biodegradability: Modified Zahn-Wellens Test”. The results showed degradation of 98% after 12 days, with approximately 30% after 3 h and 75% after 5 days.
These results suggest that potassium isobutyl xanthate will be inherently biodegradable and it is not expected to persist in the environment.

Validity criteria fulfilled:

not specified

Interpretation of results:

inherently biodegradable

Conclusions:

- The SEX , the subject of this dossier) is expected to exhibit very similar toxicity to Potassium isobutyl xanthate (CAS No.13001-46-2), which is also xanthate compound. Comparable metabolism would occur. The IUCLID datasheet describes an aerobic biodegradation test for potassium isobutyl xanthate following the OECD Guide-line 302B “Inherent biodegradability: Modified Zahn-Wellens Test”. The results showed degradation of 98% after 12 days, with approximately 30% after 3 h and 75% after 5 days. These results suggest that potassium isobutyl xanthate will be inherently biodegradable and it is not expected to persist in the environment.

Executive summary:

- The Reaction mass of SEX, the subject of this dossier) is expected to exhibit very similar toxicity to Potassium isobutyl xanthate (CAS No.13001-46-2), which is also xanthate compound. Comparable metabolism would occur. The IUCLID datasheet describes an aerobic biodegradation test for potassium isobutyl xanthate following the OECD Guide-line 302B “Inherent biodegradability: Modified Zahn-Wellens Test”. The results showed degradation of 98% after 12 days, with approximately 30% after 3 h and 75% after 5 days.

These results suggest that potassium isobutyl xanthate will be inherently biodegradable and it is not expected to persist in the environment.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

other: published data

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

SEX readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the Biodegradation in water of carbon disulphide (CS2) need to be considered in the assessment of SEX . Well Study performed.

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

yes

Remarks:

activated sludge was used as an inoculum

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

The activated sludge was preconditioned to reduce the endogenous respiration rates. To this end the sludge (200 mgdry weight) was aerated for one week. The sludge was diluted to a concentration of 2 mg dry weight/l in the bottles.

Duration of test (contact time):

28 d

Initial conc.:

ca. 5 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

study was conducted according to OECD no 301 D guideline with a slight modification, described under details of inoculum

Reference substance:

acetic acid, sodium salt

Parameter:

% degradation (DOC removal)

Value:

> 80

Sampling time:

1 wk

This study shows that CS2 is readily biodegradable.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The biodegradation of CS2 was >80 % after 28 days of exposure, therefore CS2 is readily biodegradable.
Sodium ethyl xanthate readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the Biodegradation in water of carbon disulphide (CS2) need to be considered in the assessment of Sodium ethyl xanthate.
These results suggest that Sodium ethyl xanthate will be readily biodegradable and it is not expected to persist in the environment.

Executive summary:

The biodegradation of CS2 was >80 % after 28 days of exposure, therefore CS2 is readily biodegradable.

Reaction mass of SEX readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the Biodegradation in water of carbon disulphide (CS2) need to be considered in the assessment of SEX.

These results suggest that SEX will be readily biodegradable and it is not expected to persist in the environment.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Data waiving:

other justification

Justification for data waiving:

other:

Reference 4

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

A sufficiently well reported study to be able to judge result as reliable. This study examined many chemicals and has been judged reliable by the OECD during the assessment of a number of chemical substances under the OECD HPV programme. Ethyl Alcohol (ethanol) is both reagents used in the manufacture, as well as decomposition products of xanthates. Therefore, the Biodegradation in water of Ethyl Alcohol need to be considered in the assessment of SEX .

Qualifier:

according to guideline

Guideline:

other: see 'principles of method'

Principles of method if other than guideline:

Test carried out to the guideline: BOD (Standard methods for the examination of water and waste water 1971. 13th ed, American Public Health Assoc, NY. Test based on measuring dissolved oxygen concentration changes.

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): no data
- Water filtered: yes
- Type and size of filter used, if any: glass wool

Duration of test (contact time):

ca. 20 d

Initial conc.:

ca. 3 mg/L

Based on:

test mat.

Initial conc.:

ca. 7 mg/L

Based on:

test mat.

Initial conc.:

ca. 10 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

acetic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

ca. 74

Sampling time:

5 d

Parameter:

% degradation (O2 consumption)

Value:

ca. 74

Sampling time:

10 d

Parameter:

% degradation (O2 consumption)

Value:

ca. 95

Sampling time:

15 d

Parameter:

% degradation (O2 consumption)

Value:

ca. 84

Sampling time:

20 d

Parameter:

COD

Value:

1.99 g O2/g test mat.

Results with reference substance:

5 day: 76%, 10 day: 82%, 20 day: 96% degradation

Measured COD is 95% of theoretical value.

Validity criteria fulfilled:

yes

Remarks:

reference material showed degradability

Interpretation of results:

readily biodegradable

Conclusions:

Since the degradation exceeded 60% within 10 days, the substance meets the criteria for classification as readily biodegradable.
The biodegradation of Ethyl Alcohol was >60 % after 10 days of exposure, therefore Ethyl Alcohol is readily biodegradable.SEX readily decomposes to ethyl Alcohol, especially in the presence of moisture/water. Ethyl Alcohol is both reagents used in the manufacture, as well as decomposition products.
Therefore, the Biodegradation in water of Ethyl Alcohol need to be considered in the assessment of SEX. These results suggest that SEX will be readily biodegradable and it is not expected to persist in the environment.

Executive summary:

The biodegradation of ethanol was assessed at a number of concentrations using a non-adapted domestic sewage innoculum in a freshwater medium using a 20 day study.. Rapid degradation was observed. Based on the results of this study, ethanol meets the criteria to be classified as readily biodegradable. This study is classified as acceptable and satisfies the guideline requirement for a ready biodegradation study.

Results synopsis BOD5=74%, BOD15=95%.

Description of key information

When water is added to SEX it reacts with water to form the others substances: alcohol, sodium carbonate, trithiocarbonate and carbon disulphide.

Carbon disulphide (CAS number 75–15–0) it is the major decomposition product, which is liquid and have to be considered.

The biodegradation of CS2 was >80 % after 28 days of exposure, therefore CS2 is readily biodegradable. SEX readily decomposes to carbon disulphide, especially in the presence of moisture/water.

Therefore, the Biodegradation in water of carbon disulphide (CS2) need to be considered in the assessment of SEX.

The biodegradation of Ethyl Alcohol was >60 % after 10 days of exposure, therefore Ethyl Alcohol is readily biodegradable. SEX readily decomposes to ethyl Alcohol, especially in the presence of moisture/water. Ethyl Alcohol is both reagents used in the manufacture, as well as decomposition products.

Therefore, the Biodegradation in water of Ethyl Alcohol need to be considered in the assessment of SEX. These results suggest that SEX will be readily biodegradable and it is not expected to persist in the environment.

These results suggest that SEX will be readily biodegradable and it is not expected to persist in the environment.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

When water is added to SEX it reacts with water to form the others substances: alcohol, sodium carbonate, trithiocarbonate and carbon disulphide.

Carbon disulphide (CAS number 75–15–0) it is the major decomposition product, which is liquid and have to be considered.

The biodegradation of CS2 was >80 % after 28 days of exposure, therefore CS2 is readily biodegradable. SEX readily decomposes to carbon disulphide, especially in the presence of moisture/water.

Therefore, the Biodegradation in water of carbon disulphide (CS2) need to be considered in the assessment of SEX.

The biodegradation of Ethyl Alcohol was >60 % after 10 days of exposure, therefore Ethyl Alcohol is readily biodegradable. SEX readily decomposes to ethyl Alcohol, especially in the presence of moisture/water. Ethyl Alcohol is both reagents used in the manufacture, as well as decomposition products.

Therefore, the Biodegradation in water of Ethyl Alcohol need to be considered in the assessment of SEX. These results suggest that SEX will be readily biodegradable and it is not expected to persist in the environment.

These results suggest that SEX will be readily biodegradable and it is not expected to persist in the environment.