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NICNAS assessments are carried out in conjunction with the Australian Government Department of the Environment, Water, Heritage and the Arts (DEWHA), which carries out the environmental assessments for NICNAS. This assessment is specifically focused only on the assessment of risks to the environment.
NICNAS has two major programs: the assessment of the health and environmental effects of new industrial chemicals prior to importation or manufacture; and the other focussing on the assessment of chemicals already in use in Australia in response to specific concerns about their health or environmental effects.
There is an established mechanism within NICNAS for prioritising and assessing the many thousands of existing chemicals in use in Australia. Chemicals selected for assessment are referred to as Priority Existing Chemicals.
This Priority Existing Chemical report has been prepared by the Director, NICNAS, in accordance with the Act. Under the Act manufacturers and importers of Priority Existing Chemicals are required to apply for assessment. Applicants for assessment are given a draft copy of the report and 28 days to advise the Director of any errors. Following the correction of any errors, the Director provides applicants and other interested parties with a copy of the draft assessment report for consideration. This is a period of public comment lasting for 28 days during which requests for variation of the report may be made. Where variations are requested the Director’s decision concerning each request is made available to each respondent and to other interested parties (for a further period of 28 days). Notices in relation to public comment and decisions made appear in the Commonwealth Chemical Gazette. A person may apply (within 28 days) to the Administrative Appeals Tribunal (AAT) for review of decision(s) where the Director has refused to vary the draft report as requested.
In accordance with the Act, publication of this report revokes the declaration of this chemical as a priority existing chemical, therefore manufacturers and importers wishing to introduce this chemical in the future need not apply for assessment. However, manufacturers and importers need to be aware of their duty to provide any new information to NICNAS, as required under Section 64 of the Act.
For the purposes of Section 78(1) of the Act, copies of assessment reports for New and Existing Chemical assessments are freely available from the web (www.nicnas.gov.au). Summary Reports are published in the Commonwealth Chemical Gazette (http://www.nicnas.gov.au/Publications/Chemical_Gazette.asp).
Copies of this and other priority existing chemical reports are available on the NICNAS website. Hard copies are available from NICNAS from the following address:
GPO Box 58, Sydney NSW 2001, AUSTRALIA
Tel: +61 (2) 8577 8800
Fax: +6881 (2) 8577 8888
Free call: 1800 638 528
Other information about NICNAS (also available on request and on the NICNAS website) includes:
Preface 3
Overview 6
Recommendations 13
Secondary Notification 29
Acronyms and Abbreviations 30
List of Tables 34
List of Figures 35
1.Introduction 37
1.1Declaration 37
1.2Objectives of the assessment 37
1.3Sources of information 37
1.4Peer review 38
1.5Applicants 39
2.Background 41
2.1International perspective 41
2.1.1International assessments 42
2.2Australian perspective 42
3.Chemical Identity and Composition 43
3.1Chemical identity 43
3.1.1Chemical name 43
3.1.2Registry numbers 43
3.1.3Other names 43
3.1.4Molecular formula and structure 43
3.2Physical and chemical properties 43
3.2.1Physical state 43
3.2.2Physical properties 44
Table 3. . Physical properties of sodium cyanide (NaCN) 44
3.2.3Chemical properties 46
Table 3. Selected common metal-cyanide complexes and compounds 46
3.2.4Conversion factors 47
Table 3.. Conversion factors 47
3.3Methods of analysis 47
3.3.1Analysis of cyanide compounds 47
3.3.2Atmospheric monitoring 50
3.3.3Biological monitoring 51
4.Manufacture, Importation and Use 52
4.1Sodium cyanide in Australia 52
4.2Manufacture, formulation and transport 52
4.2.1Manufacture 52
4.2.2Formulation and transport of products 53
Table 4.. Typical constituents of formulated solid sodium cyanide 53
Table 4.. Typical constituents of liquid sodium cyanide 54
5.1Imports and exports 54
5.2Uses of sodium cyanide in Australia 55
5.2.1Overall range of uses 55
5.2.2Gold ore beneficiation and processing 56
8.Sources of Environmental Exposure 67
8.1Environmental release of cyanides generally 67
8.1.1Natural sources of cyanide 67
14.1.1Anthropogenic sources of cyanide 69
14.1.2National emissions of cyanide (National Pollutant Inventory) 70
17.1Release from sodium cyanide manufacture and industrial use 74
17.1.1General comments 74
17.1.2Sodium cyanide manufacturing facilities 74
17.1.3Cyanide use in gold beneficiation and recovery 75
Table 5.. Tailings, TSF pore water (0-2.0 m), decant and reclaim water concentrations (mg/L) of cyanate, thiocyanate and cyanide forms (after Staunton, 1991 b-d) 78
19.1.1Flotation use in base metal ore processing 80
19.1.2Electroplating, metal cleaning and metal surface treatment 82
22.1.1Other uses 84
22.2Release via sewerage plant effluent 84
22.3Release as a result of unintentional incidents 85
22.3.1Manufacturing facilities 85
22.3.2Transportation 85
Table 5.. Environmental incidents that have occurred with cyanide during transport 88
22.3.3Use and disposal at gold or other mineral processing facilities 91
Table 5.. Environmental incidents involving cyanide at gold ore processing facilities or heap leach operations 92
22.4Summary of sources of environmental exposure 99
23.Environmental Fate 102
23.1Overview of fate of sodium cyanide 102
23.2General degradation pathways 102
23.3Environmental transport and distribution 104
23.3.1Free cyanide 104
23.3.2Volatilisation of HCN 104
23.3.3Atmospheric fate of HCN 105
23.3.4Complexation 107
23.3.5Adsorption and mobility in soil 107
Table 6.. Composition of leachate and % attenuation of applied cyanide in soil columns in laboratory tests (from Staunton, 1991c). 108
23.3.6Cyanide complex precipitation 109
23.4Abiotic degradation 109
23.4.1Hydrolysis 109
23.4.2Photolysis 109
23.4.3Formation of cyanates and other products 110
23.4.4Thiocyanate formation 110
23.5Biotic degradation 110
23.5.1Aerobic conditions 110
23.5.2Anaerobic conditions 111
23.6Fate of cyanide in tailings storage facilities 111
23.6.1Tailings constituents 111
Table 6.. Microbial cyanide degradation pathways (adapted from Meehan, 2000) 111
23.6.2Processes for detoxifying or recovering cyanide in tailings 113
23.6.3Transformation in TSFs and migration 114
23.6.4Fate modelling and monitoring data 116
26.1Fate of cyanide in heap leach ore heaps 119
26.1.1Changes in concentration and composition 119
Table 6.. Cyanide products (mg/L) in drainage from an inactive ore heap 120
26.1.2Migration in seepage from heap leach operations 121
26.2Fate of cyanide in landfills 121
26.3Fate of cyanide in sewerage systems 121
26.4Summary of environmental fate 122
27.Environmental Exposure Assessment 124
27.1Exposure at manufacturing facilities 124
27.2Exposure during transport 125
27.3Exposure during use for gold beneficiation and recovery 126
27.3.1Wildlife in the vicinity of TSFs and mine infrastructure 126
27.3.2Recent wildlife interaction studies in arid/semi-arid areas of Western Australia 129
27.3.3Exposure of wildlife at tank leach operations 131
29.1.1Exposure of wildlife at heap leach operations 134
29.1.2Exposure during release of HCN to the atmosphere 136
29.1.3Total exposure for wildlife from gold mining use 137
Table 7.. Potential cyanide concentrations in mine site process solutions and wastes 139
Table 7.. Summary of potential oral (drinking water) exposure to cyanide in mine site process solutions and wastes by wildlife (0.01-1.5 kg body weight) 142
30.1Exposure from flotation use in base metal ore processing 142
30.2Exposure from electroplating, metal cleaning and metal surface treatment 142
30.3Summary of environmental exposure assessment 142
31.Kinetics and Metabolism in Animals 146
31.1Absorption 146
31.1.1Inhalation 146
31.1.2Oral 146
31.1.3Dermal 147
31.2Distribution and macromolecular binding 147
31.2.1Inhalation 147
31.2.2Oral 147
31.2.3Dermal 148
31.3Metabolism/biotransformation 148
31.4Elimination/Excretion 150
31.4.1Inhalation 150
31.4.2Oral 151
31.4.3Dermal 151
31.5Summary of kinetics and metabolism in animals 151
32.Environmental Hazard Assessment 152
1.1Mode of action of cyanide toxicity 152
1.2Effects on avian species 153
32.1.1Acute toxicity 153
Table 9.. Avian acute oral toxicity studies with sodium cyanide 158
34.1.1Repeat dose/dietary toxicity 165
Table 9.. Sublethal acute oral avian toxicity studies with potassium cyanide 167
Table 9.. Avian water exposure cyanide toxicity studies 172
35.1.1Toxicologically significant forms of cyanide to birds 174
Table 9.. Estimated LC50 values for NaCN to various bird species, based on LD50 data and median bird bodyweights in the corresponding studies 175
1.3Effects on mammalian species 176
35.1.2Acute toxicity 176
Table 9.. Acute inhalation toxicity studies with hydrogen cyanide and mammals 178
Table 9.. Acute oral toxicity to mammals of sodium cyanide, potassium cyanide and hydrogen cyanide 181
41.1.1Repeat dose toxicity 184
Table 9.. Summary of repeat-dose inhalation toxicity 186
Table 9.. Summary of repeat-dose oral toxicity 190
44.1.1Mutagenicity 197
46.1.1Carcinogenicity 198
46.1.2Fertility 198
46.1.3Developmental toxicity 199
1.4Effects on terrestrial plants 200
1.5Effects on terrestrial arthropods 202
1.6Effects on micro-organisms 203
1.7Effects on aquatic organisms 204
50.1.1Freshwater aquatic toxicity data 204
50.1.2Marine aquatic toxicity data 204
Table 9.. Summary of selected freshwater aquatic toxicity data for cyanide 205
Table 9.. Summary of selected marine aquatic toxicity data for cyanide 207
50.1.3Chronic effects on fish and invertebrates 210
Table 9.. Symptoms of cyanide exposure in freshwater fish 210
50.1.4Factors affecting the aquatic toxicity of cyanide 211
Table 9.. Aquatic toxicity (LC50) to fish of metal-cyanide complexes and compounds and cyanide breakdown products 213
Table 9.. Comparison of toxicity data (96-h LC50 or 72-h EC50) for free and complexed cyanide (mg/L) to two Australian fish species, one marine microalga and one marine mollusc 214
1.8Toxicity reference values (TRVs) 215
55.1.1The TRV approach and summary of the TRVs determined 215
Table 9.. Derived mammalian, avian and aquatic TRVs for cyanide 215
Table 9.. NOAEL-based AFs for use in deriving wildlife TRVs 216
55.1.2Selection of Toxicity Reference Values (TRVs) 217
1.9Field observations of terrestrial and aerial wildlife mortality at gold processing facilities 220
59.1.1International data on wildlife impacts 220
Table 9.. Selected incidences of wildlife mortality from cyanide at Nevada Gold Mine TSFs (1986 to 1991) 221
59.1.2Wildlife poisoning incidents in Australia 224
Table 9.. Avian incidents at TSF and heap leach areas at five gold mines in the Top End of the Northern Territory based on a survey by ERA Environmental Services (1995). 227
63.1.1Issues regarding monitoring of wildlife at TSFs 232
63.1.2Toxicity of other tailings components 233
1.10Summary of environmental hazard assessment 234
64.Environmental Risk Characterisation 238
1.11Risks during manufacture and transport 238
64.1Risks to wildlife with use in gold mines 239
64.1.1Risk quotients for drinking water exposure based on laboratory data 239
Table 10.. Estimated risk quotients for birds (0.01-1.5 kg bw) potentially exposed to cyanide solutions 240
Table 10.. Estimated risk quotients for mammals (0.01-1.5 kg bw) potentially exposed to cyanide solutions 242
66.1.1Other factors influencing the risk to wildlife 242
66.1.2Risk to wildlife based on field data 243
70.1Risks to aquatic life 246
70.2Risks to vegetation 247
70.3Risks to wildlife with use for flotation 248
70.4Risks from industrial uses 248
70.5Summary of risk characterisation 248
71.Current Environmental Risk Management 251
71.1General environmental controls and monitoring 251
71.2Major hazard facilities (MHF) 252
71.3Dangerous goods management 253
71.3.1Storage and handling of dangerous goods 253
73.1.1Transportation of dangerous goods 254
76.1.1Packaging specifications for dangerous goods 257
76.1.2Complementary state/territory legislation 258
Table 11.. Primary dangerous goods legislation and guidance 258
76.1.3Procurement of sodium cyanide 259
76.2Hazard communication 260
76.2.1Labelling and hazard warning systems 260
76.2.2Material safety data sheets (MSDS) 260
78.1Emissions management and monitoring 262
78.1.1Pollution management 262
Table 11.. Primary environment protection legislation for pollution management 262
78.1.2National Pollutant Inventory (NPI) Program 263
78.2Prevention of environmental contamination 263
78.2.1General framework 263
78.2.2Groundwater management 264
78.2.3TSF management 265
81.1Heap leach operation and management 269
Table 11.. Summary of key concerns of heap pads and heaps 269
81.2Cyanide waste management 270
81.2.1International requirements for cyanide waste management 270
81.2.2Sea dumping of cyanide wastes 271
81.2.3Trans-national waste movement 272
81.2.4States and territories waste management 272
Table 11.. Primary state and territory waste management legislation and guidance 273
81.3Environmental media quality guidelines for cyanide and products 274
81.3.1Water quality guidelines for the protection of aquatic life 274
Table 11.. Water quality guidelines for cyanide for aquatic ecosystem protection 275
81.3.2Guidelines for WAD CN or metallocyanide complexes 278
81.3.3Water quality monitoring 278
81.4Wildlife protection and biodiversity conservation 279
81.4.1Migratory waterbird conservation 279
84.1.1Australian wildlife protection legislation and policies 280
86.1.1Water quality guideline levels to protect wildlife 289
88.1Chemical manufacturing industry initiatives 290
88.1.1Manufacturing facility programs 290
88.1.2Responsible Care® program 290
88.2Mining, metal extraction and cyanide management 292
88.2.1General comments 292
88.2.2Sustainable development program for the mining industry 293
88.2.3Wildlife management at mining operations 293
88.2.4International Cyanide Management Code (ICMC) 294
88.3Practical measures to protect wildlife at gold mines 295
88.3.1Limiting access and the use of hazing techniques 295
89.1.1Reducing the attractiveness of facilities to wildlife 297
89.1.2Using a combined approach of controlling CN concentrations and minimising exposure 298
89.2Summary of current risk management 300
90.Conclusions 302
90.1Use in Australia 302
90.2Environmental exposure 302
90.3Environmental risk assessment 303
90.4Current risk management 305
Appendix 1 -
Methods for analysing cyanide 308
Appendix 2 -
Effect of Tailing Storage Facilities on Bird Species 313
Appendix 3 - Classification under the Globally Harmonized System 319
Appendix 4 -
Response Measures for Sodium Cyanide Release 321
References 325