CEPA Environmental Registry - Environmental Code of Practice for Base Metals Smelters and Refineries: Code of Practice, Canadian Environmental Protection Act, 1999.

This section presents recommended mitigative measures for activities of potential environmental concern. These recommendations were derived from regulatory and non-regulatory standards, in particular on environmental practices, published by various agencies and organizations.

The overall objectives of the Code are to identify and promote recommended practices as requirements for new facilities and as goals for continual improvements for existing facilities.

Application of the recommendations to individual facilities may involve practices that are not mentioned in this Code but that may achieve an equivalent or better level of environmental protection.

Site-specific municipal, provincial/territorial, federal, and legal requirements must be taken into account where they exist. Recommendations that are not legally binding or conditions set down by insurance companies or financial, lending institutions, may also be applicable.

For some of the recommendations presented, following explanatory text is provided.

4.1 ENVIRONMENTAL MANAGEMENT SYSTEMS

In the context of this Code of Practice, the term 'environmental management systems' is used to capture an organized set of activities, actions, processes, and procedures that go beyond legal requirements in helping to ensure that facilities have minimal adverse impact on the environment in which they operate. The effective development and implementation of environmental management systems should also facilitate efforts to achieve continual improvement in the overall environmental performance of base metals smelters and refineries.

The recommendations presented in this section take into account policies, principles, and commitments advanced by Environment Canada, the Canadian Council of Ministers of the Environment, provinces/territories, the Mining Association of Canada, and other organizations.

4.1.1 Environmental Policy Statement

The policy should relay that protection of the environment is a top organizational priority and that commitment to continual improvement of environmental performance and compliance with laws and regulations are the guiding principles of the organization.

4.1.2 Environmental Management Systems

RECOMMENDATION R 102

Each facility should develop, implement, and maintain an environmental management system in accordance with ISO 14001³⁴ or an equivalent standard or system.

The management system should, among other things, ensure a process of continual improvement as well as compliance with environmental regulations and voluntary commitments.

4.1.3 Environmental Management Plans

RECOMMENDATION R 103

Each facility should develop and implement a site-specific environmental management plan, consistent with the Environmental Management Plan Guidance Document for the Base Metals Smelting Sector.³⁵ The plan should include, as a minimum, the following:

company and site information;
environmental policy statement;
environmental performance requirements;
air quality management systems;
water quality management systems;
solids management systems;
land management systems;
pollution prevention planning;
emissions reduction options, targets, and schedules;
environmental management systems and auditing;
community relationships;
communication procedures; and
periodic environmental management plan review for effectiveness and continual improvement.

4.1.4 Environmental Assessment

RECOMMENDATION R 104

Environmental assessment principles should be followed by companies for new and significantly modified or expanded facilities, consistent with the Canadian Environmental Assessment Agency Reference Guide,³⁶ Table 1.

The development of new facilities and changes to existing facilities that could significantly increase releases to the environment should be subjected to an environmental assessment process, with the aim of identifying potential problems and formulating solutions that address them.

Companies should follow assessment principles consistent with Table 1 in the Reference Guide of the Canadian Environmental Assessment Agency when conducting the assessment. The environmental assessment process should also comply with all other applicable provincial/territorial and municipal requirements, should be initiated during the early stages of pre-project planning, and should continue as an iterative process through the project design, construction, and operations phases. Consideration should be given to potential impacts on air quality, water quality, water supply and use, land use, flora and fauna, and local infrastructure.

4.1.5 Pollution Prevention Planning

RECOMMENDATION R 105

Each facility should develop and implement a pollution prevention plan, consistent with Environment Canada's Pollution Prevention Planning Handbook³⁷ or in compliance with any Pollution Prevention Plan Notification issued under the Canadian Environmental Protection Act, 1999.

The intention of prevention is to eliminate the root cause of pollution, rather than treating the symptoms. For example, pollution prevention relies on source reduction to address inefficiencies in the production of goods and services at their source, resulting in reduced waste and releases. Thus, pollution prevention planning is a systematic comprehensive method of identifying options to minimize or avoid the creation of pollutants and waste.

4.1.6 Emergency Planning

RECOMMENDATION R 106

Each facility should develop and make publicly available an environmental emergency plan, consistent with Environment Canada's Implementation Guidelines for Part 8 of the Canadian Environmental Protection Act, 1999 - Environmental Emergency Plans.³⁸

Existing emergency response plans can be modified or used as is, if they are consistent with the recommendations spelled out in the above guideline. An effective plan would address, among other things, aspects of prevention, preparedness, response, and recovery for an uncontrolled, unplanned, or accidental release of a toxic substance or hazardous substance in the facility. Companies should review their hazardous chemicals and storage facilities and develop an environmental emergency plan. They should also verify if the Environmental Emergency Regulations under CEPA 1999 apply to any of the substances on their premises and if the laws of other jurisdictions (such as provinces and municipalities) may also apply.

4.1.7 Decommissioning Planning

RECOMMENDATION R 107

A facility should begin planning for decommissioning in the design stage of the project life cycle for new facilities and as early as possible in the operating stage for existing facilities. Site closures and associated decommissioning activities should be undertaken by the facility, consistent with the National Guidelines for Decommissioning Industrial Sites.³⁹

This could help to identify areas of the facility whose closure or decommissioning may cause an environmental problem. This could also help to implement operational procedures and management practices that could prevent or reduce site contamination. Decommissioning should be carried out in a way that ensures that no or limited adverse risk to the environment or human health remains after closure.

4.1.8 Environmental Training

RECOMMENDATION R 108

Each facility should establish and maintain procedures to identify its environmental training needs and ensure that all personnel who work in areas that may create a significant adverse impact upon the environment have received training.

The facility should also require that contractors working on its behalf are able to demonstrate that their employees have appropriate training so that they can avoid adverse impacts on the environment as a result of their activities. The environmental training program should include:

4.1.9 Environmental Facility Inspection

4.1.10 Environmental Auditing

RECOMMENDATION R 110

Each facility should conduct periodic environmental audits by internal, corporate, or third-party auditors.

The audit should be conducted throughout the operating life of the facility as a means of assessing environmental risk, ensuring conformance with regulatory, appropriate non-regulatory, and corporate requirements, and identifying opportunities for improving environmental performance. The audit could be conducted internally or by corporate or third-party auditors. The recommendations advanced in this Code of Practice should be included in the audit criteria.

4.1.11 Environmental Performance Indicators

RECOMMENDATION R 111

Each facility should develop a set of environmental performance indicators that can provide an overall measure of the facility's environmental performance.

These indicators would include a broad and practical set of ecological and economic elements that offer significant opportunities to link environmental performance to financial performance. An example of an environmental performance indicator is expressing pollutant emissions in kilograms per tonne of product manufactured, such as kilograms of sulphur dioxide per tonne of copper.

4.1.12 Product Stewardship

RECOMMENDATION R 112

Each company should develop and implement a product stewardship program aimed at minimizing the environmental impacts associated with the products used and produced by the facility and under the control of the company.

Under this program, the company takes full responsibility for the environmental impacts associated with the operational, use, and handling aspects of the products used and produced by its facilities, at every stage of each product's life cycle that is under the direct control of the company.

4.1.13 Public Reporting

RECOMMENDATION R 113

Documented procedures for the monitoring and reporting of environmental performance to the public should be developed and implemented by the facility, consistent with the Guidance Document for Reporting Releases from the Base Metals Smelting Sector⁴⁰ and taking into account the Global Reporting Initiative's Sustainability Reporting Guidelines⁴¹ for the mining and metals sector.

4.1.14 Community Advisory Panel

RECOMMENDATION R 114

Each facility should establish a Community Advisory Panel with representatives from the surrounding community, in order to provide a forum for the review and discussion of facility operations and associated environmental and other concerns.

The objective of the forum should be to address community concerns related to the potential adverse environmental, health, and safety impacts that may arise as a result of the operational activities of the facility. The forum should be used, among other things, to provide opportunity to the community to raise issues of concern, if any, to discuss topics important to them, to obtain information and/or clarification on issues of concern, and also to offer input or advice to the company on those issues. Issues of concern could be site-specific or general concerns regarding, for example, emergency planning, release levels, risk assessment, etc.

4.2 ATMOSPHERIC RELEASES MANAGEMENT

4.2.1 Prevention and Control of Fugitive Air Emissions

RECOMMENDATION R 201

Each facility should identify potential sources of fugitive emissions and should prevent or control those emissions through the use of appropriate mitigative measures. These sources may include unpaved roads, storage piles, material conveyance systems, waste disposal piles, and leaks from processes and buildings.

To prevent fugitive emissions and minimize losses, it is essential to implement good housekeeping and best environmental practices. These would, for example, include enclosure of process equipment, use of covered or enclosed conveyors and transfer points, implementation of Leak Detection and Repair programs, covering of major stockpiles, spray coating of smaller and temporary stockpiles, and paving of yards.

4.2.2 Collection and Control of Process Air Emissions

RECOMMENDATION R 202

Each facility should ensure that air pollution control equipment is adequately sized, designed, constructed, operated, and maintained to contain and control pollutant releases to ambient air from all plant processes.

Air pollution control equipment designed on the basis of sound engineering considerations should be able to maintain control of releases to the ambient air from all operational sources and at different operational conditions, including in the event of operational upsets.

4.2.3 Total Particulate Matter Emissions Guidelines

RECOMMENDATION R 203

Each facility should be designed and operated to achieve the following recommended release concentrations for total particulate matter after the emission control device of less than 50 mg/Nm³

Emission testing should be carried out in a manner that is consistent with Environment Canada's Guidance Document for Reporting Releases from the Base Metals Smelting Sector⁴² or with Reference Methods for Source Testing: Measurement of Releases of Particulate from Stationary Sources,⁴³ as amended from time to time.

In cases where a fabric filter emission control system does not have a stack, emission testing should be carried out in a manner that is consistent with the U.S. Environmental Protection Agency's Method 5D: Determination of Particulate Matter Emissions from Positive Pressure Fabric Filters.⁴⁴ It is recognized that particulate release estimates for facilities without stacks are typically less accurate than release estimates for facilities equipped with stacks and that relative accuracy must be taken into account in assessing the results of tests conducted in accordance with Method 5D.

4.2.4 Sulphur Fixation Guidelines

RECOMMENDATION R 204

Each facility should consider use of low sulphur feed and recycled materials to reduce emissions of sulphur dioxide.
Each existing facility should be designed and operated to achieve a minimum sulphur fixation rate of 90% by a committed timetable.
Each new copper, lead and zinc smelter should be designed and operated to achieve a minimum sulphur fixation rate of 99%.
Each new nickel smelter should be designed and operated to achieve a minimum sulphur fixation rate of 96%.

Sulphur can be fixed in metallurgical processes by at least one of the following four processes:⁴⁵

All of the processes benefit from high sulphur dioxide concentrations in the gas stream; however, the production of liquid sulphur dioxide and the production of elemental sulphur both require high sulphur dioxide concentrations. This can be achieved by using oxygen-enriched air in the process. The production of sulphuric acid is the most widely used, because it is the easiest and least expensive sulphur fixation method, and the market for sulphuric acid is generally much larger than that for the other products.⁴⁶

The sulphur fixation values can be calculated in accordance with the methodology applied by Hatch Associates Ltd.⁴⁷

4.2.5 Mercury Emissions Guidelines

RECOMMENDATION R 205

Each existing facility should be designed and operated to limit air release loadings to less than 2 grams of mercury per tonne of finished product.
Each new or expanded facility should be designed and operated to limit air release loadings in accordance with the following:
1. less than 0.2 grams of mercury per tonne production of finished zinc, nickel, and lead; and
2. less than 1 gram of mercury per tonne production of finished copper.

Numerical targets set for the release of mercury from base metals smelters, under the Canada-wide Standards (see Appendix A), are as follows:

4.2.6 Dioxins and Furans Emissions Guidelines

RECOMMENDATION R 206

Each existing facility should be designed and operated to limit release concentrations of dioxins and furans to less than 100 pg ITEQ*/Rm³.
Each new facility should be designed and operated to limit release concentrations of dioxins and furans to less than 32 pg ITEQ*/Rm³.

* ITEQ = International Toxicity Equivalency Quotient.

Dioxins and furans are persistent, bioaccumulative and toxic substances. The federal Toxics Substances Management Policy and the Canadian Council of Ministers of Environment Policy on Management of Toxic Substances calls for the virtual elimination of such substances. An ultimate objective is to reduce the concentration of dioxins and furans in air emissions from base metal smelters to below the "level of quantification" which has been determined to be 32 pg/Rm³.

4.2.7 Metals Emissions Limit Targets

RECOMMENDATION R 207

Each facility should develop facility emission reduction targets for and timetables to achieve reductions in releases of arsenic, cadmium, lead, nickel, mercury, and other metals of concern, taking into account facility emission reduction targets for sulphur dioxide and particulate matter, pollution prevention and control options, and performances for various feeds, smelting processes, and emission control systems.

4.2.8 Air Releases Reporting

RECOMMENDATION R 208

Each facility should measure or estimate and report releases, consistent with the Guidance Document for Reporting Releases from the Base Metals Smelting Sector⁴⁹ and in accordance with the notice requiring submission of data for the National Pollutant Release Inventory.⁵⁰

4.2.9 Ambient Air Quality Objectives

RECOMMENDATION R 209

In addition to the source performance recommendations of R 203 and R 204, each facility should design and operate air emission prevention and control systems, taking into account local conditions and the following ambient air quality objectives, standards, criteria and guidelines:

1. Canadian Council of Ministers of the Environment, Canadian Environmental Quality Objectives, Canadian National Ambient Air Quality Objectives: Appendix 1, 1999.

2. Canadian Council of Ministers of the Environment, Canada-wide Standards for Particulate Matter and Ozone, June 5-6, 2000.

3. Ontario Ministry of the Environment's Ambient Air Quality Criteria for Arsenic and Its Compounds.

* Reference level is the level above which there are demonstrated effects on human health and/or the environment.

National ambient air quality objectives are benchmarks to assess the impact of human activities on air quality and ensure that emission control policies are successfully protecting human health and the environment.

Another management tool for establishing and estimating the magnitude of risk is the application of effects-based critical loads. A critical load may be defined as the amount of deposition required for contaminant levels to reach threshold effect values in receiving media when a "steady state" has been achieved.⁵¹

The critical load concept is used in developing emission control policies, as illustrated by the following applications:

Environment Canada has developed generic aquatic and terrestrial critical loads for six metals based on reasonable worst-case conditions of the Canadian Shield (i.e., soft, circumneutral to acidic lake waters and acidic, sandy soils). These critical loads are applicable to facilities located on the Shield or having similar conditions in their vicinity.⁵⁴ In particular, sandy soils are ubiquitous throughout most of Canada. The probabilistic approach utilized yielded 25th- and 10th-percentile critical loads, representing levels protective of the endpoint organisms under 75% and 90% of receiving environment conditions, respectively.

Estimated critical loads can be compared with actual deposition rates monitored near a releasing facility and thereby act as one of the environmental quality objective indicators for evaluating the effectiveness of utilized pollution controls by the facility. It can take decades (or more) for contaminant concentrations in receiving media to reach steady state. Critical loads have the advantage of providing an early indication of whether the current monitored deposition rate could cause contaminant levels to exceed threshold effect values once steady state is established.

Detailed descriptions of methodology for modelling and critical load calculations can be found in the Bibliography section.

4.2.10 Ambient Air Quality Monitoring

RECOMMENDATION R 210

Each facility should develop and implement an ambient air quality monitoring program in consultation with the regulatory bodies having authority over the facility. This program should include the sampling and analysis of metals, particulate matter (total, PM₁₀, and PM_2.5), sulphur dioxide, and other pollutants of concern, taking into account:

the location of release sources under the control of the facility operator; and
local meteorological conditions and probable maximum pollutant deposition areas.

4.3 WATER AND WASTEWATER MANAGEMENT

4.3.1 Water Use/Reuse

RECOMMENDATION R 301

Water use should be minimized, to the maximum extent practicable, possibly through the recycling or reuse of water and the cascading of cooling water and wastewater between production processes using lower-quality water.

4.3.2 Wastewater Collection

RECOMMENDATION R 302

All wastewater streams that may exceed the effluent criteria of R 304 should be directed to a treatment facility prior to discharge to the environment.

To the extent practicable, system designs should provide for the segregation and collection of similar wastewaters (e.g., oily, acid, cleaning, and sanitary wastes).

4.3.3 Wastewater Containment Sizing

RECOMMENDATION R 303

Wastewater collection and containment systems should be designed to contain the maximum volume of liquid that could reasonably be expected to be in storage for the following conditions:

the maximum volume of wastewater that would be accumulated during the time required to shut down wastewater generating processes, plus 50%;
110% of the volume that could enter the containment system in the event of a leak, spill, or other like incident; or
the accumulated precipitation from a 24-hour, 50-year storm (return period) for outdoor containments.

4.3.4 Water Effluent Guidelines

RECOMMENDATION R 304

Wastewater treatment facilities should be designed, constructed, operated, and maintained to achieve the following effluent quality prior to release:

On a continuous basis:
pH 6.0-9.5

Maximum monthly mean concentration:
Total suspended solids 15.0 mg/L
Arsenic 0.5 mg/L
Copper 0.3 mg/L
Cyanide* 1.0 mg/L
Lead 0.2 mg/L
Nickel 0.5 mg/L
Zinc 0.5 mg/L

* If cyanide is used in the process.

Non-acutely lethal effluent:
No more than 50% mortality of Daphnia magna and rainbow trout test species in 100% effluent when tested in accordance with Environment Canada Reference Methods 1/RM/13⁵⁵ and 1/RM/14.⁵⁶

4.3.5 Water Effluent Reporting

RECOMMENDATION R 305

Effluents should be monitored, tested, estimated and reported, consistent with Environment Canada's Guidance Document for the Sampling and Analysis of Metal Mining Effluents⁵⁷ and Guidance Document for Flow Measurement of Metal Mining Effluents⁵⁸ and in accordance with the notice requiring submission of data for the National Pollutant Release Inventory.⁵⁹

4.3.6 Ambient Water Quality Guidelines

RECOMMENDATION R 306

In addition to the source performance recommendations of R 304 and R 305, each facility should design and operate effluent discharge systems, taking into account local conditions and the following ambient water quality objectives:

* Canadian Council of Ministers of the Environment, Canadian Environmental Quality Guidelines for the Protection of Freshwater Aquatic Life (Summary Table update December 2003).

** Ammonia (total) is used to describe the sum of ammonia (NH₃) and ammonium (NH₄⁺).

Critical loads can be used to indicate whether deposition of sulphates, metals, and metal compounds to surface waters is above or below a level that would lead to environmental impacts.

Critical loads may be defined as the amount of deposition required for contaminant levels to reach threshold effect values in receiving media. For surface waters, the critical load is the rate of deposition to the water body or to areas draining to it that would lead (accounting for the fraction retained in the soil) to minimal effects on sensitive aquatic organisms.⁶⁰

The estimated critical loads can be compared with actual deposition rates near a releasing facility and thereby act as one of the environmental quality objective indicators for evaluating the effectiveness of utilized pollution controls by the facility (see also Section 4.2.9 for more details on critical loads).

The total ammonia guideline is not a specific value, but rather a range of values over various pHs and temperatures. That is because ammonia toxicity is affected by various factors, among which are pH, the most important, and temperature.

Table 4 provides total ammonia guidelines over a range of pHs (6.0-9.5) and temperatures (0-30°C) based upon the un-ionized ammonia guideline of 0.019 mg/L and the following two equations:⁶¹

where:
f = fraction of total ammonia that is un-ionized.
pK_a = dissociation constant from equation 1.

4.3.7 Aquatic Environmental Effects Monitoring

RECOMMENDATION R 307

Each facility that discharges to a receiving water should develop and implement an aquatic environmental effects monitoring program, consistent with Environment Canada's Metal Mining Guidance Document for Aquatic Environmental Effects Monitoring.⁶³

4.4 WASTE MANAGEMENT

4.4.1 Reduction, Reuse, and Recycling

RECOMMENDATION R 401

Each facility should develop, implement, and maintain a waste reduction, reuse, and recycling program. The program should be one that:

identifies opportunities for in-plant reduction, reuse, and recycling of wastes;
develops and implements plans for the evaluation and implementation of reduction, reuse, and recycling opportunities;
identifies and evaluates market opportunities for wastes with a view to maximizing waste material reduction, reuse, and recycling (this includes the sale of by-products that would otherwise be considered wastes); and
develops and implements a research and development program for reducing, reusing, and recycling residual wastes.

4.4.2 Location and Construction of Waste Disposal Sites

RECOMMENDATION R 402

Expansions to existing waste disposal sites and the design and construction of new sites should be undertaken so as to ensure that:

the site plan is updated to clearly show the location and dimensions of the new or expanded waste disposal site;
the perimeter of the disposal area is far enough away from all watercourses to prevent contamination by runoff, seepage, or fugitive emissions;
the surface drainage from off-site areas is diverted around the disposal area;
the expanded area is hidden from view by fences, berms, or buffer zones; and
future beneficial uses of the waste disposal site after its closure have been considered.

4.4.3 Development of Solid Waste Disposal Sites

RECOMMENDATION R 403

Solid waste disposal sites should be developed in accordance with the following practices:

the disposal area should be developed in modules or cells;
all wastes should be placed such that they have physical and chemical stability suitable for land reuse, if the disposal area is reclaimed;
contouring, capping, and reclamation of cells should be undertaken throughout the operating life of the site; and
all disposal sites should be reclaimed for beneficial uses before final closure or restricted from public access if they cannot be reclaimed.

4.4.4 Management of Waste Disposal Sites

RECOMMENDATION R 404

All waste disposal sites should be managed in accordance with documented, site-specific waste management plans approved by the appropriate regulatory bodies having authority over the facility so that:

solid, liquid, and hazardous wastes are transferred only to facilities specifically designed, approved, and operated for that purpose;
access to the site is controlled and disposal activities are supervised by trained personnel; and
records are maintained of the types, approximate quantities, and point of origin of the wastes.

4.4.5 Monitoring of Waste Disposal Sites

RECOMMENDATION R 405

A groundwater monitoring program should be developed for all waste disposal sites in accordance with the following guidelines:

a permanent system of appropriately located piezometers and wells should be provided;
a program of pre-operational monitoring of groundwater regimes should be initiated;
groundwater samples should be collected at least quarterly; and
each groundwater sample should be analyzed for pH, total dissolved solids, and other appropriate site-specific parameters.

4.4.6 Waste Reporting

RECOMMENDATION R 406

Wastes disposed of and transferred should be reported, in accordance with the notice requiring submission of data for the National Pollutant Release Inventory.⁶⁴

4.4.7 Waste Management

RECOMMENDATION R 407

Waste should be managed consistent with the Guidance Document for Management of Wastes from the Base Metals Smelting Sector.⁶⁵

34 Canadian Standards Association, Environmental Management Systems - Specification with Guidance for Use, CAN/CSA-ISO 14001-96, 1996.

35 Hatch Associates Ltd., Environmental Management Plan Guidance Document for the Base Metals Smelting Sector, prepared for Environment Canada, March 14, 2001.

36 Canadian Environmental Assessment Agency, Reference Guide: Determining Whether a Project is Likely to Cause Significant Adverse Environmental Effects (www.ceaa-acee.gc.ca/013/0001/0008/guide3_e.htm).

38 Environment Canada, Implementation Guidelines for Part 8 of the Canadian Environmental Protection Act, 1999, Environmental Emergency Plans, September 2003, ISBN 0-662-33797-2 (www.ec.gc.ca/CEPARegistry/guidelines/impl_guid/toc.cfm).

39 Canadian Council of Ministers of the Environment, National Guidelines for Decommissioning Industrial Sites, Report No. CCME-TS/WM-TRE013E, March 1991, ISBN 0-662-18705-9.

40 Hatch Associates Ltd., Guidance Document for Reporting Releases from the Base Metals Smelting Sector, prepared for Environment Canada, October 2001.

42 Hatch Associates Ltd., Guidance Document for Reporting Releases from the Base Metals Smelting Sector, prepared for Environment Canada, October 2001.

43 Environment Canada, Reference Methods for Source Testing: Measurement of Releases of Particulate from Stationary Sources, Report EPS 1/RM/8, December 1993.

44 U.S. Environmental Protection Agency, Method 5D: Determination of Releases of Particulate from Positive Pressure Fabric Filters, Federal Register, CFR 40 Part 60, Appendix A, pp. 647-651, January 7, 1996.

45 Riekkola-Vanhanen, M., Finnish Expert Report on Best Available Techniques in Nickel Production, Finnish Environment Institute, Helsinki, 1999, ISBN 952-11-0507-0.

47 Hatch Associates Ltd., Implementation Scenario for Proposed Emission Standards for Particulate Matter and Sulphur Dioxide for the Base Metal Smelting Sector, December 2001.

49 Hatch Associates Ltd., Guidance Document for Reporting Releases from the Base Metals Smelting Sector, prepared for Environment Canada, October 2001.

51 Doyle, P.J., D.W. Gutzman, M.I. Sheppard, S.C. Sheppard, G.A. Bird, and D. Hrebenyk, An ecological risk assessment of air emissions of trace metals from copper and zinc production facilities, Human and Ecological Risk Assessment, 9(2): 607-636, 2003.

52 Skeffington, R., The use of critical loads in environmental policy making: a critical appraisal, Environmental Science and Technology, 33(11): 245 A-252 A, 1999 (http://pubs.acs.org/hotartcl/est/99/jun/skeff.html).

53 United Nations Economic Commission for Europe, The 1994 Oslo Protocol on Further Reductions of Sulphur Emissions (www.unece.org/env/lrtap/fsulf_h1.htm).

54 Environment Canada and Health Canada, Canadian Environmental Protection Act, 1999, Priority Substances List Assessment Report: Releases from Primary and Secondary Copper Smelters and Copper Refineries; Releases from Primary and Secondary Zinc Smelters and Zinc Refineries, 2001, ISBN 0-662-29871-3.

55 Environment Canada, Biological Test Method: Reference Method for Determining Acute Lethality of Effluents to Rainbow Trout, Report EPS 1/RM/13, Second Edition, December 2000.

56 Environment Canada, Biological Test Method: Reference Method for Determining Acute Lethality of Effluents to Daphnia magna, Report EPS 1/RM/14, Second Edition, December 2000.

57 Environment Canada, Guidance Document for the Sampling and Analysis of Metal Mining Effluents, EPS 2/MM/5, April 2001.

58 Environment Canada, Guidance Document for Flow Measurement of Metal Mining Effluents, EPS 2/MM/4, April 2001.

61 Canadian Council of Ministers of the Environment, Canadian Water Quality Guidelines for Aquatic Life: Ammonia Fact Sheet, 2000, ISBN 1-89699-34-1.

65 Hatch Associates Ltd., Guidance Document for Management of Wastes from the Base Metals Smelting Sector, prepared for Environment Canada, July 2004.

Environmental Code of Practice for Base Metals Smelters and Refineries: Code of Practice, Canadian Environmental Protection Act, 1999.

4 RECOMMENDED ENVIRONMENTAL PROTECTION PRACTICES