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Environmental fate & pathways

Biodegradation in water: screening tests

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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
Justification for type of information:
Reaction mass of SIBX are related compound to PIBX
Qualifier:
according to
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 sodium 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 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 sodium isobutyl xanthate will be inherently biodegradable and it is not expected to persist in the environment.
Executive summary:

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 degradationof 98% after 12 days, with approximately 30% after 3 h and 75% after 5 days.

These results suggest that sodium isobutyl xanthate will be inherently biodegradableand it is not expected to persist in the environment.

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:
Reaction mass of SIBX 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 Reaction mass of SIBX. Well Study performed.
Qualifier:
according to
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.
Reaction mass of SIBX 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 Reaction mass of SIBX.
These results suggest that Reaction mass of SIBX 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 SIBX 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 Reaction mass of SIBX.

These results suggest that Reaction mass of SIBX will be readily biodegradable and it is not expected to persist in the environment.

Endpoint:
biodegradation in water: ready biodegradability
Data waiving:
other justification
Justification for data waiving:
other:
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:
2-methylpropan-1-ol /Isobutyl alcohol/ is both reagents used in the manufacture of Reaction mass of 2-methylpropan-1-ol and sodium O-isobutyl dithiocarbonate and sodium hydroxide . Therefore, 2-methylpropan-1-ol /Isobutyl alcohol/ need to be considered in the assessment of Reaction mass of 2-methylpropan-1-ol and sodium O-isobutyl dithiocarbonate and sodium hydroxide
Qualifier:
according to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Principles of method if other than guideline:
Coarse-filtered mixture of domestic treatment plant effluents and rich soil microorganisms were added to BOD dilution water at a concentration of 0.1
mL per liter. BOD dilution water is fortified with specified minerals and buffered to pH 7.2. Seven BOD bottles were prepared with and without test substance added. One was measured for DO immediately and duplicate bottles measured at days 5, 15, and 28 using a YSI dissolved O2 meter.
Bottles were incubated at 20° C. DO measurements for the test and standard substance (ethylene glycol) were corrected for the blank values.
GLP compliance:
no
Oxygen conditions:
aerobic
Inoculum or test system:
other: seed (settled sewage-treated effluent, or commercial Polyseed BOD seed)
Details on inoculum:
Coarse-filtered mixture of domestic treatment plant effluents and rich soil microorganisms were added to BOD dilution water at a concentration of 0.1 mL per liter.
Duration of test (contact time):
28 d
Details on study design:
- Sealed 300 ml bottle
- Temperature 20°C
- BOD dilution water is fortified with specified minerals and buffered to pH 7.2.
- Seven BOD bottles were prepared with and without test substance added.
- One was measured for DO immediately and duplicate bottles measured at days 5, 15, and 28 using a YSI dissolved 02 meter.
- Bottles were incubated at 20 °C.
- DO measurements for the test and standard substance (ethylene glycol) were corrected for the blank values.
Parameter:
% degradation (O2 consumption)
Value:
70 - 80
Sampling time:
28 d
Details on results:
Kinetic of test substance (in %):
5 day = 14%,
15 day = 74%,
28 days = 74%
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The biodegradation of Isobutyl Alcohol was >74 % after 28 days of exposure, therefore Isobutyl Alcohol is readily biodegradable.Reaction mass of SIBX readily decomposes to Isobutyl Alcohol, especially in the presence of moisture/water. Isobutyl Alcohol is both reagents used in the manufacture, as well as decomposition products.
Therefore, the Biodegradation in water of Isobutyl Alcohol need to be considered in the assessment of Reaction mass of SIBX. These results suggest that Reaction mass of SIBX will be readily biodegradable and it is not expected to persist in the environment.
Executive summary:

The biodegradation ofIsobutyl Alcohol was >74% after 28 days of exposure, therefore Isobutyl Alcohol is readily biodegradable. Reaction mass of SIBX readily decomposes to IsobutylAlcohol, especially in the presence of moisture/water.Isobutyl Alcohol is both reagents used in the manufacture, as well as decomposition products.

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

Description of key information

When water is added to Reaction mass of SIBX 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. Sodium isobutyl 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 Reaction mass of SIBX.
The biodegradation of Isobutyl Alcohol was >74 % after 28 days of exposure, therefore Isobutyl Alcohol is readily biodegradable. Sodium isobutyl xanthate readily decomposes to Isobutyl Alcohol, especially in the presence of moisture/water. Isobutyl Alcohol is both reagents used in the manufacture, as well as decomposition products.
Therefore, the Biodegradation in water of Isobutyl Alcohol need to be considered in the assessment of sodium isobutyl xanthate.
These results suggest that Reaction mass of SIBX 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 Reaction mass of SIBX 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. Sodium isobutyl 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 isobutyl xanthate.

The biodegradation of Isobutyl Alcohol was >74 % after 28 days of exposure, therefore Isobutyl Alcohol is readily biodegradable. Reaction mass of SIBX readily decomposes to Isobutyl Alcohol, especially in the presence of moisture/water. Isobutyl Alcohol is both reagents used in the manufacture, as well as decomposition products.

Therefore, the Biodegradation in water of Isobutyl Alcohol need to be considered in the assessment of sodium isobutyl xanthate.

These results suggest that Reaction mass of SIBXwill be readily biodegradable and it is not expected to persist in the environment.