Appendix 3 - Classification under the Globally Harmonized System
Classifications under the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) (UNECE, 2005) will come into force when the GHS is adopted by the Australian Government and promulgated into Commonwealth legislation. GHS background information and documentation are available at:
http://www.unece.org/trans/danger/publi/ghs/ghs_welcome_e.html
The environmental hazard classification of sodium cyanide using the GHS classification system is presented in Table A3-1. As yet, in regard to toxicity in the environment GHS only addresses acute and chronic aquatic toxicity. As sodium cyanide dissolves readily in water to form free cyanide (i.e. cyanide present as molecular HCN and ionic CN- - Sections 3.3.1 and 23.3.1), the aquatic toxicity of sodium cyanide has been based on data for free cyanide.
Based on the data presented for free cyanide toxicity in Section 1.7, sodium cyanide is very highly toxic to various species of fish, aquatic invertebrates and algae (EC/LC50 < 1mg CN/L). Some tests show lower toxicity, which is likely to be due to differences in water conditions and the way the tests were conducted, as well as species differences (Section 50.1.4). From available data, cyanide appears to be much less toxic to aquatic macrophytes (EC50 > 10 mg CN/L).
At present, GHS classifications for chronic aquatic toxicity are based on the acute toxicity of a substance together with consideration of its environmental persistence and bioaccumulation behaviour, rather than on actual chronic toxicity data (NOECs). The high water solubility of sodium cyanide and low Log Pow value < 4 (Section 3.2.2) mean that cyanide is unlikely to partition to fat and bioaccumulate, studies with animals show that it is metabolised to thiocyanate and eliminated (Sections 31.3-31.4), and it has not been found to biomagnify in food webs or cycle extensively in ecosystems, probably because of its rapid breakdown (Eisler et al., 1999). The rate of degradation or loss by volatilisation as HCN depends on conditions (Section 23), but in natural environments it is likely that the free cyanide would be removed or transformed by biotic or abiotic processes (volatilisation, conversion to cyanate etc) at a faster rate than that indicated as meeting the description ‘rapidly degradable’ in the GHS guidance document (Part 4, Environmental Hazards: Section 4.1.2.10). Under the current GHS classification for chronic toxicity, free cyanide would then be categorised as ‘Not classified’.
However, the GHS guidance document notes that it is the intention that the scheme should be further developed to accommodate actual chronic toxicity data. Chronic toxicity tests with fish (Section 50.1.3) show that it may have high chronic toxicity (NOEC in the range 10-100 µg CN/L for most measured effects in freshwater fish, but 10 µg CN/L for spawning and egg production). While chronic effects are unlikely to arise from a single exposure event, such effects could arise if there were continuous or repeated release at concentrations below acutely toxic levels. Hence this classification is likely to be different once actual chronic toxicity data are considered in the GHS classification system.
Table A3-1. GHS classification for environmental hazards of sodium cyanide.
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Hazard
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Classification
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Hazard communication
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Environmental hazard
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Acute toxicity
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|
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Aquatic organisms (fish, aquatic invertebrates and algae)
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Category 1
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Symbol: Environment
Signal word: Warning
Hazard statement: Very toxic to aquatic life (Code H400)
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Chronic toxicity
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|
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Aquatic organisms
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Not classified
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Symbol: No symbol is used
Signal word: No signal word is used
Hazard statement: No chronic hazard statement is used
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Appendix 4 -
Response Measures for Sodium Cyanide Release
SPILL RESPONSE AND DISPOSAL
This appendix provides a general consensus of measures to be taken in the event of an accidental environmental release of sodium cyanide. It does not replace or override specific advice provided by manufacturers and suppliers.
91.Immediate Action: -
Immediate action is required following a spill incident. Initiate emergency spill response procedures immediately. Cyanide spills should be cleaned up as soon as safe to do so.
92.Communication: -
Notify emergency services (Police and/or Fire Brigade), appropriate personnel, government safety, health and environment protection authorities of spill incident.
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Contact manufacturer for advice on spill management (include emergency contact phone number in MSDS)
93.Evacuation/Access Restriction: -
Evacuate spill area of all unprotected personnel. Move away, upwind and upgradient.
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Restrict access to spill site until clean-up is completed and validated. Vacate area completely if spill is in a confined space. Ensure spill area is well ventilated to minimise gas accumulation.
94.Training: -
Ensure that only adequately trained personnel are involved in spill management, cleanup and validation.
95.Personal Protective Equipment: -
Avoid all contact (skin, eye) and inhalation. Full protective clothing should be worn by personnel working in contaminated areas to prevent skin and eye contamination and inhalation of dusts, gases (e.g. hydrogen cyanide) and mists.
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PPE – refer to MSDS or seek manufacturer’s advice. After use, wash all PPE prior to storing or reusing, or dispose of appropriately.
96.Spill Source Control: -
Stop or reduce leaks only if safe to do so. Wear PPE.
97.Containment: -
Contain spills within a bund and avoid run-off to drains, waterways, and sewers. Do not wash off or allow this chemical to enter drains, waterways, or sewers.
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Use absorbent materials (e.g. sandbags, soil, sand, kitty litter or other inert material) to contain spill. Do not use sawdust, which is acidic and may lead to HCN gas generation, or other reactive materials.
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Cover spill (e.g. with tarp) in wet weather. Ensure adequate ventilation to avoid HCN gas accumulation.
98.Cleanup Procedures: -
For Small Spills of Solid Material to Soil:
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Recover (shovel/sweep) all visible material and seal in clean, dry, properly labelled drums. Keep spilt material dry. Do not wash to drain. Avoid generating dusts or mists. Reclaim and re-use product as much as possible.
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Spill area residues and collected contaminated material can be treated with an appropriate neutralising reagent. Contact manufacturer for advice on suitable neutralising reagents and methods. Treatment of spill area residues may include excess of dilute sodium hypochlorite, calcium hypochlorite, or ferrous sulphate after the addition of soda ash or lime to raise the pH to greater than 10.5.
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Sodium hypochlorite and calcium hypochlorite should not be used in or near sensitive aquatic environments. Do not flush treated residues to waterways or sewer.
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Contact manufacturer and government waste disposal authority for advice on appropriate spill management strategy for cleanup residues.
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Store and transport collected residues appropriately (refer to MSDS).
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For Large Spills of Solid Material to Soil:
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Contact emergency services and supplier for spill management advice. Liaise with appropriate personnel, government safety, health and environment protection authorities. In general, manage as for small spills of solid material (refer above). Do not attempt to neutralise in bulk without expert assistance.
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For Small Spills of Liquid Solution to Soil:
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Soak up spill with suitable absorbent material that does not react with spilt material. Remove a conservative amount of soil. Collect all contaminated soil and seal in clean, dry, properly labelled drums.
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Treat residue at spill area and in collected contaminated soil with neutralising reagent on advice of manufacturer. Contact manufacturer and government waste disposal authority for advice on appropriate spill management strategy for cleanup residues.
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Store and transport collected residues appropriately (refer to MSDS).
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For Large Spills of Liquid Solution to Soil:
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Contact emergency services and supplier for spill management advice. Liaise with appropriate personnel, government safety, health and environment protection authorities.
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Remove top layers of contaminated soil for treatment in-situ or ex-situ (e.g. lined ponds, wastewater treatment plants, salvage containers). Do not attempt to neutralise in bulk without expert assistance. Contact manufacturer for advice on suitable neutralising reagents and methods.
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Store and transport collected residues appropriately (refer to MSDS).
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For Spills (solids/liquids) to Waterways and Sewers:
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Notify emergency services immediately. Liaise with appropriate personnel, government safety, health and environment protection authorities. Do not attempt to neutralise in bulk without expert assistance.
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Spills to waterways may not require treatment due to natural attenuation. Spills to waterways can potentially be detoxified, but expert advice is required for this treatment (contact manufacturer).
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Neutralisation and Detoxification:
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Contaminated media may be detoxified with appropriate treatment reactants as advised by the manufacturer. Avoid contact with detoxification substances/solutions, which are corrosive.
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Treatment chemicals may potentially include sodium hypochlorite, calcium hypochlorite and ferrous sulphate. Do not use water (alone), acids or strong oxidizing reagents.
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Do not use sodium hypochlorite and calcium hypochlorite in or near sensitive aquatic environments. Hypochlorites are toxic to aquatic organisms. Use only where immediate run-off water can be contained and treated.
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Neutralising reagents may have narrow pH limits within which they react effectively.
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Neutralising reagents must never be used without the full knowledge of their limitations. If used in bulk, they can initiate hazardous reactions or generate excessive heat and toxic byproducts. With heat, HCN and ammonia gases may evolve. Contact with water (alone) may cause HCN gas to be released.
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If sodium hypochlorite or calcium hypochlorite is used, allow adequate time (approximately 1 to 24 hours, but contact manufacturer for specific advice) for chemical reaction and complete decomposition to occur. The detoxification procedure converts the cyanide ion to the cyanate ion that on continued reaction breaks down to carbon dioxide and nitrogen.
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Reaction with ferrous sulphate produces a relatively stable ferrocyanide compound. HCN may evolve if exposure to sunlight occurs. Ferrous sulphate increases the generation of HCN gas, and produces a residue that is potentially toxic to animals (e.g. cattle, wildlife) if consumed.
99.Cleanup Validation: -
Validation of spill site cleanup may include visual assessment, surface soil sampling and analysis, and air monitoring for hydrogen cyanide (HCN) using specific, calibrated gas detection equipment. Contact relevant environment protection authority for advice.
100.Disposal/Recycling: -
Contact manufacturer for advice on appropriate spill management strategy for cleanup residues. Liaise with government waste management authority. Treatment, storage, transportation, and disposal of waste must be in accordance with applicable Federal, state/territory and Local Government regulatory requirements.
AUSTRALIAN STANDARD AS1678
Australian Standard AS1678.6.0.009 provides the following spill response recommendations:
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Immediately contact Police or Fire Brigade.
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Spill or leak area should be isolated immediately for at least 25 m in all directions.
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Keep unauthorised personnel away. Keep upwind and on higher ground.
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Ventilate enclosed spaces before entering.
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Shut off electrical equipment and leave off.
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Send message to Police and Fire Brigade. Tell them location, material, UN Number, quantity and emergency contact (name and phone number) as well as condition of vehicle and damage observed.
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For Large Spills: Consider initial downward evacuation for at least 250 m.
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Do not touch or walk through spilled material.
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Do not touch damaged containers unless wearing appropriate protective clothing.
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Stop leak if safe to do so.
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Prevent entry into waterways, drains or confined areas.
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Cover with plastic sheet to prevent spreading.
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Absorb with earth, sand or other non-combustible material and transfer to container.
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Do not get water inside containers.
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Seek expert advice on handling and disposal.
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