Potassium O-pentyl 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:

comparable to guideline study with acceptable restrictions

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 Potassium amyl xanthate (CAS No. 2720-73-2), 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 Potassium amyl xanthate (CAS No. 2720 -73 -2), 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:

Potassium amyl 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 potassium amyl xanthate. 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

Remarks:

Laboratories Arnhem CRL F92145 T92-03-04

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.
Potassium amyl 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 potassium amyl xanthate.
These results suggest that potassium amyl 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.

Potassium amyl 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 potassium amyl xanthate.

These results suggest that potassium amyl xanthate 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:

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:

Purity of test material not specified. 1-pentyl alcohol (Amyl alcohol) is both reagents used in the manufacture, as well as decomposition products of xanthates. Therefore, the Biodegradation in water of 1-pentyl alcohol (Amyl alcohol) need to be considered in the assessment of potassium amyl xanthate.

Qualifier:

equivalent or similar to guideline

Guideline:

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

Principles of method if other than guideline:

Standard methodology, which is similar to OECD Guideline 301D . These tests measured consumption of oxygen (biochemical oxygen demand, BOD) in vessels containing test substance, non-adapted inoculum from domestic sewage treatment plants, and test media prepared according to APHA guidelines.

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure):sewage, domestic, non-adapted
Microbial cultures were grown in medium in 1L or 2 L flasks maintained on a rotary shaker at 25 degree C for 48 hr.
Cells were collected by centrifuge, washed in 0.10M phosphate buffer (pH 7.1), and resuspended in the same buffer.
Warburg flasks contained 1.0 ml of sewage cell suspension, 100 umoles of phosphate buffer (pH 7.1) and 3.0 umoles of substrate. Additional tests with glucose were conducted to assess toxicity of test substance to the inoculum.
Oxygen uptake was measured at 30 degree C.

Duration of test (contact time):

ca. 30 d

Initial conc.:

ca. 2.9 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

other: glucose, 2 mg/l

Parameter:

% degradation (O2 consumption)

Value:

ca. 34

Sampling time:

2 d

Parameter:

% degradation (O2 consumption)

Value:

ca. 52

Sampling time:

5 d

Parameter:

% degradation (O2 consumption)

Value:

ca. 62

Sampling time:

10 d

Parameter:

% degradation (O2 consumption)

Value:

ca. 52

Sampling time:

30 d

Details on results:

A 30-day aerobic test with 1-pentyl alcohol and reported 34% biooxidation by day 2, 52% by day 5, 62% by day 10, and 52% by day 30.

Parameter:

BOD5

Value:

4.1 mg O2/g test mat.

Results with reference substance:

The concentration of oxygen consumed in suspensions exposed to 1-pentyl alcohol was 2.7 mg/l, 4.1 mg/l, 4.9 mg/l, and 4.1 mg/l for days 2, 5, 10, and 30, respectively.

The concentration of oxygen consumed in suspensions exposed to 1-pentyl alcohol was 2.7 mg/l, 4.1 mg/l, 4.9 mg/l, and 4.1 mg/l for days 2, 5, 10, and 30, respectively

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Since the degradation exceeded 62% within 10 days, the substance meets the criteria for classification as readily biodegradable.
The biodegradation of 1-pentyl alcohol (Amyl alcohol) was >62 % after 10 days of exposure, therefore 1-pentyl alcohol (Amyl alcohol) is readily biodegradable. Potassium amyl xanthate readily decomposes to Amyl Alcohol, especially in the presence of moisture/water. Amyl Alcohol is both reagents used in the manufacture, as well as decomposition products.
Therefore, the Biodegradation in water of Amyl Alcohol need to be considered in the assessment of potassium amyl xanthate. These results suggest that potassium amyl xanthate will be readily biodegradable and it is not expected to persist in the environment.

Executive summary:

In this study, Dias and Alexander (1971) conducted a 30-day aerobic test with 1-pentyl alcohol and reported 34% biooxidation by day 2, 52% by day 5, 62% by day 10, and 52% by day 30. In the same study, the authors measured the biooxidation of 2-methyl butyl alcohol, which was measured at 48, 62, 74, and 52% after 2, 5, 10, and 30 days, respectively. Values for both alcohols were corrected for oxygen consumption in bottles with no test substance present, which accounted for the lower rate on day 30.

Results synopsis

BOD2=34%,

BOD5=52%,

BOD10=62%

BOD30=52%

Description of key information

When water is added to Potassium amyl xanthate it reacts with water to form the others substances: alcohol, potassium 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. Potassium amyl 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 potassium amyl xanthate.
The biodegradation of 1-pentyl alcohol (Amyl alcohol) was >62 % after 10 days of exposure, therefore 1-pentyl alcohol (Amyl alcohol) is readily biodegradable. Potassium amyl xanthate readily decomposes to Amyl Alcohol, especially in the presence of moisture/water.  Amyl  Alcohol is both reagents used in the manufacture, as well as decomposition products.
Therefore, the Biodegradation in water of Amyl  Alcohol need to be considered in the assessment of potassium  amyl  xanthate. These results suggest that potassium  amyl xanthate will be readily biodegradable and it is not expected to persist in the environment.
These results suggest that potassium amyl xanthate 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 Potassium amyl xanthate it reacts with water to form the others substances: alcohol, potassium 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. Potassium amyl 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 potassium amyl xanthate.

The biodegradation of 1-pentyl alcohol (Amyl alcohol) was >62 % after 10 days of exposure, therefore 1-pentyl alcohol (Amyl alcohol) is readily biodegradable. Potassium amyl xanthate readily decomposes to Amyl Alcohol, especially in the presence of moisture/water. Amyl Alcohol is both reagents used in the manufacture, as well as decomposition products.

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

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