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EC number: 205-440-9 | CAS number: 140-90-9
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Mode of degradation in actual use
Administrative data
- Endpoint:
- mode of degradation in actual use
- Type of information:
- migrated information: read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: see 'Remark'
- Remarks:
- This report reviews available degradation data on xanthates focusing on the seasonal variation in Swedish tailing ponds in subarctic climate. The results summarise available scientific infromation applying it to realistic conditions in tailing ponds and are therefore rated as scientifically acceptable. Read-across justification: Target substance belongs into the group of substances called xanthates. The alkali metal xanthates, as the target substance also is, are generally prepared from the reaction of the alkoxide, which reacts with carbon disulphide to give the xanthate. These substances contain common functional group which is dithiocarbonate (-OCSS-). Though they are structural analogues with the target substance. All these analogue substances are used in similar use application as water solutions. All xanthates decompose in the presence of water. In neutral to alkaline media, they will release carbon disulphide, particular alcohol (ethanol), and carbonates and dithiocarbonates. Carbon disulphide is the major and the most volatile and the most hazardous decomposition products of xanthates. As the xanthates can be considered as a group of substances which have structural similarity and similar behaviour in contact with water and in the physiological processes, their hydrolysis and biodegradation as well as ecotoxicological adverse effects to aquatic organisms are expected to be similar. Therefore, and in order to avoid the unnecessary animal testing, the read-across data from the analogue xanthates is used to evaluate the short-term and long-term toxicity to fish. In addition, the decomposition rate and the most important pathways are evaluated based on the available data on the analogues when there is no data available for the target substance.
Cross-referenceopen allclose all
- Reason / purpose for cross-reference:
- reference to same study
- Reason / purpose for cross-reference:
- reference to other study
Data source
Reference
- Reference Type:
- publication
- Title:
- Unnamed
- Year:
- 1 988
Materials and methods
- Principles of method if other than guideline:
- The degradation of xanthates were simulated using realistic conditions (monthly water temperatures and inflow rates) in tailing ponds in central Sweden. The impact of alternative technologies to xanthate concentrations in the tailings pond water and discharge was estimated by a numerical model. For xanthates, both a (conservative) constant degradation half-life of 47 days (B), and a calculated temperature-dependant half-life (C) was used. They were compared to a conservative non-degradable substance (A) with t1/2 of 100000 days. Re-generation from dixanthogen was excluded from the modelling. The simulations were not verified with measurements (as it was not known how much dixanthogen was formed and at which rate at it was degraded).
- GLP compliance:
- no
- Type of study / information:
- A review of available publications on (hydrolytical) degradation of xanthates. The impact of pH and temperature on degradation half-lives in pure solutions have been recalculated based on literature data, and compared to modelled data in tailings water. Abiotic and/or biotic reaction processes in tailings pond are additionally simulated based on the key parameters obtained from literature.
Test material
- Reference substance name:
- Potassium O-pentyl dithiocarbonate
- EC Number:
- 220-329-5
- EC Name:
- Potassium O-pentyl dithiocarbonate
- Cas Number:
- 2720-73-2
- IUPAC Name:
- potassium O-pentyl dithiocarbonate
- Details on test material:
- Examples of alkyl xanthates used: sodium isopropyl xanthate, (potassium) isobutyl xanthate, (potassium) amyl xanthate. A single rate is proposed for all xanthates.
Constituent 1
Results and discussion
Any other information on results incl. tables
In summary, the modelled concentrations of xanthates in the tailings pond 0.14 - 0.22 mg/L
for a conventional treatment method at dose of 1 g xanthate/ton ore (see Table below).A very coarse calculation for the concentration in discharge water would end up in concentrations < 1 µg/L.
With three different treatment tehcniques, the concntrations of xanthates in the tailings pond can either increase or decrease ranging 0.05 - 0.23 mg/L. More importantly, these techniques decreased the amount of xanthates discharged 0 - 50 %.
The author referred to measured levels of Walterson (1984) in Swedish tailing ponds. Levels of 0.02 - 42 mg/L xanthates in tailing ponds and 0 - 16800 µg/L in discharge water (calculated as –OCS2equivalent xanthate weight without the carbon chain). This kind of modelling provides a good tool to study the impact of key parameters like temperature, annual precipitation of rain and snow and their seasonal variations. The possibility of a separate biological tratment was pointed our as one possibility to further reduce the xanthate discharges to the surface water.
Table. Summary of xanthate concentrations measured and simulated at the Swedish tailing ponds.
|
Measured (Walterson 1984) * |
Simulated conventional (35 % recycled water) |
Simulated reduced drainage |
Simulated thickened disposal |
Simulated thickened disposal with reduced drainage |
Dose |
11 - 162 |
1 g/tonne ore |
1 g/tonne ore |
1 g/tonne ore |
1 g/tonne ore |
Concentr. in pond (mg/L) |
0.02 – 42
|
0.14 – 0.22
|
0.15 – 0.23
|
0.05 - 0.14
|
0.06 – 0.18 |
Concentr. in discha rge water (µg/L) |
0 - 16800 |
calc. (0.07 – 0.36) |
10 – 20 % of conventional |
23 – 30 % of conventional |
0 – 50 % of convention al |
*as –OCS2equivalent xanthate weight without the carbon chain
Attachment:
Figure I-1. Schematic presentation of the water flows at an ore concentrator for an underground mine with conventional deposition technique.
Figure I-9. Mean monthly values of inflow rates and water temperatures for the pond in Figure I-1 (in Central Sweden).
Table I-2. Half-lives (t1/2) for xanthates at water temperatures used in the example at pH 7.5 (from Part II)
Figure I-10. Monthly variations of amounts of substances A, B and C discharged to the receiving water.
Figure I-11. Monthly variations of concentration A, C and B in the pond.
Figure I-12. Scematic presentations of water flows at an ore concentrator with thickened disposal technique.
Figure I_13. Monthly variations in amounts of substance A discharged to the receiving water from the pond for conventional (A) and thickened technique (D).
Figure I-14. Monthly variations of xanthates discharged to the receiving water from the pond for conventional (C) and thickened (D) technique.
Figure I-15. Inflow from the drainage are for both the natural and reduced area.
Figure I-16. Concentrations of a) conservative substance A and b) xanthate at snowmelt using the three techniques.
Figure I-17. Discharged amounts of a) conservative substance A and b) xanhtate at snowmelt using the three techniques.
Table I-3. Influence of accumulation of a recycled conservative substance A on discharged amounts and concentration in the pond using the three techniques
Table I-4. Amounts of substances A recycled to the proecess using the three techniques.
Table II-1. The dosage of xanthates at some Swedish ore concentratirs and outlet of xanthates or xanthate derivatives from the tailing ponds (Walterson 1984).
Applicant's summary and conclusion
- Conclusions:
- Measured levels of xanthates in Swedish tailing ponds have ranged 0.02 - 42 mg/L in tailing ponds and 0 - 16800 µg/L in discharge water (calculated as –OCS2equivalent xanthate weight without the carbon chain).
The modelled concentrations of xanthates in the tailings pond were 0.14 - 0.22 mg/L for a conventional treatment method at dose of 1 g xanthate/ton ore. A rough calculation of xanthate concentrations was < 1 µg/L.. Three different treatment tehcniques either increased or decreased xanthate concentrations in the tailings water (0.05 - 0.23 mg/L). More importantly, these techniques decreased the amount of xanthates discharged to surface water 0 - 50 %. The simulation confirms that annual temperature and seasonal variations in the rain or snow deposition are extremely important parameters when considering the use of treatment technologies for reducing xanthate levels from tailings water. - Executive summary:
This report reviews available degradation data on xanthates focusing on the seasonal variation in Swedish tailing ponds in subarctic climate. Temperature, pH and the concentration of the xanthate are among the key factors determining the degradation of xanthates in tailing ponds.
Measured levels of xanthates in Swedish tailing ponds have ranged 0.02 - 42 mg/L in tailing ponds and 0 - 16800 µg/L in discharge water (calculated as –OCS2equivalent xanthate weight without the carbon chain).
The modelled concentrations of xanthates in the tailings pond were 0.14 - 0.22 mg/L for a conventional treatment method at dose of 1 g xanthate/ton ore. A rough calculation of xanthate concentrations was < 1 µg/L. Three different treatment tehcniques either increased or decreased xanthate concentrations in the tailings water (0.05 - 0.23 mg/L). More importantly, these techniques decreased the amount of xanthates discharged to surface water 0 - 50 %. The simulation confirms that annual temperature and seasonal variations in the rain or snow deposition are extremely important parameters when considering the use of treatment technologies for reducing xanthate levels from tailings water.
The results summarise available scientific infromation applying it to realistic conditions in tailing ponds in subarctic climate and are therefore rated as scientifically acceptable.
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