Dioxin Action Plan

Foreword

Executive Summary

Introduction

Taking Action on Dioxin

Why We Should Take Action

Sources of Discharges to Air

Actions for Waste Disposal Sources

Actions for Other Sources

Application of Actions

Appendix 1

Appendix 2

Appendix 3

4 Sources of Discharges of Dioxin to Air

4.1 Source categories

Sources of dioxin in New Zealand have been assessed by the New Zealand Inventory of Dioxin Emissions.(See footnote 14) This shows that dioxin discharges to air can be placed into four categories: waste combustion, fuel combustion, metallurgical production and processing, and other sources.

Waste combustion

The burning of waste is the major source of dioxin discharges to air in New Zealand. Waste combustion takes place predominantly in open fires at landfills, in backyard fires, in commercial incineration units such as those that burn medical waste, and in combustion units that are not designed to handle waste, such as boilers. Landfill fires have the worst discharges by far.(See footnote 15) There are no municipal waste incinerators in New Zealand.

Fuel combustion

Dioxin is discharged to air whenever hydrocarbon fuels are burned. A chlorine source is required, but this can be as simple as salt present in the combustion air. Wood and coal are important industrial fuels, and discharges of dioxin depend on the fuel and the type of boiler or combustion unit in which they are burned. Wood and, to a lesser extent, coal are also used for heating buildings. The combustion of petrol and diesel in motor vehicles and the burning of used oil also discharge dioxin.

Metallurgical production and processing

This category can be divided into the manufacture and processing of iron and steel and the processing and recovery of non-ferrous metals.

Other sources

Other sources of dioxin discharges to air fall into three groups: crematoria, accidental fires, and minor miscellaneous sources including cigarette smoking, the burning of landfill gas, and chemical recovery boilers at pulp and paper mills.

The relative sizes of dioxin discharges from these categories are shown in Figure 3.

4.2 Source-by-source decision-making

In Sections 5 and 6 of this action plan, each source of dioxin discharge to air is considered separately and actions are recommended. These actions range from 'do nothing' to regulation by way of an NES under the RMA.

A set of criteria have been used (with varying degrees of formal analysis) as a basis for recommending the source-specific actions. These include the Section 32 RMA criteria of effectiveness and efficiency. Some of the criteria are related. For some sources, conflicts between different criteria exist and tradeoffs are inevitable.

Criteria for source characteristics

• Total size of source: little reduction in overall dioxin discharges can be achieved from targeting small sources.
• Potential for growth: the pie chart in Figure 3 shows the relative sizes of current sources. The introduction of a large uncontrolled and badly operated municipal waste incinerator would change the figure dramatically.
• Trends: some sources are already declining due to changes taking place for other reasons.
• Certainty of information: there is always a balance between collecting too much and not enough information. What information is collected must be accurate and representative of the source for policy-making purposes.
• Technical options: dioxin is an unwanted byproduct of many processes. Feasible control technologies or alternative processes must exist before these dioxin discharges can be reduced.

Effectiveness, cost and efficiency criteria

• Effectiveness: a dioxin discharging 'unit' may be, for example, a landfill fire, a waste incinerator, or a '44-gallon drum incinerator'. An action is judged to have high 'total effectiveness' if it would make a significant reduction in the total amount of dioxin discharged to air from all units of the same type (for example, from all landfill fires).
• Cost: most of the cost of an action will fall on a householder or company, and so the size of this cost must be considered. The 'total cost' of a recommended action should be, in the words of the Stockholm Convention on POPs, "economically viable" in the relevant sector. Costs to industry may include some initial 'up-front' costs, technology and monitoring costs. Government expenditure will also need to occur, both at a national and regional level.
• Cost-effectiveness: the reduction of dioxin discharges to air should be achieved at the lowest cost possible.

Other criteria

• Overseas action: if proposed actions differ greatly from what has been done in other countries, this may signal potential problems.
• Consistency/fairness: some degree of consistent treatment is reasonable, but taken to its extreme this criterion would lead to paralysis.

Footnotes:
14 New Zealand Inventory of Dioxin Emissions to Air, Land and Water, and Reservoir Sources. Ministry for the Environment, Wellington, March 2000.

15 Reference to 'landfill fires' in this action plan refers solely to the uncontrolled burning of waste at a landfill. It does not include the collection and burning of landfill gas.