Paradigm for Substance Flow Analyses

1 Introduction

Substance Flow Analysis (SFA) is an analytical tool used for achieving the understanding of the flow of substances through a given system defined in space and time. The substances may be elements, chemical compounds or groups of chemical compounds.

At the moment there is no agreed international guidelines for SFAs, but in recent years methodological elements of the SFA framework has been discussed within a European concerted action of SFA practitioners, ConAccount. A discussion of terminology and general technical framework of SFAs with references to the international literature can be found in the proceedings of the first ConAccount workshop (Bringezu 1997; ConAccount 1999).

In Denmark the term 'Mass Flow Analysis' (massestrømsanalyse) has traditionally been used as synonymous of 'Substance Flow Analysis'. However, in accordance with the most used international terminology the term 'Substance Flow Analysis' will be used in this paradigm as the term Mass flow Analysis in other contexts are used for analysis where the flow of more substances are aggregated on the basis of mass (Udo de Haes et al. 1997). If the analysis cover the flow of more complex materials and industrial products the analysis is most often designated 'Material Flow Analysis' (MFA).

General framework

A general technical framework for SFAs has been proposed by Udo de Haes et al. 1997. The framework takes inspiration from internationally agreed framework for Life Cycle Assessments (LCA ISO 14040).

According to this framework the SFA consists of three steps:

	Goal and system definitions
	Inventory and modelling
	Interpretation of the results

These steps are discussed further in section 2.3, but introduced here.

Goal definition

The present paradigm applies to SFAs initiated by the Danish EPA. The SFAs will typically be initiated for substances which, in different ways, are anticipated of causing environmental or health problems. The overall goal of the analyses is to provide a comprehensive view of the flow of the substance in question through the Danish society forming the fundament for considerations as regards the need and instruments for risk minimisation for the substance. Subsequent to the analysis, it may be considered further to investigate the effects of specific actions, including a more detailed analysis of the possibility of substitution of the chemical substance, etc.

In addition the analysis is aimed at providing a common understanding as regards the flow of the substance for all stakeholders in the risk minimisation process: the authorities, industry, NGOs, consumers, etc.

In combination the SFAs provide information on e.g. sources of heavy metals to solid waste incineration and may in combination be used for prioritising risk minimisation actions including more substances.

To meet the overall goal, the SFAs include determination of the main sources of discharges to the environment in Denmark (including losses to waste deposits, etc.) and explanations about what uses of the chemical substance cause these discharges.

The more specific goals of the analysis will depend on at which level of the risk minimisation process the SFA is pretended to be used. Is the aim of the analysis to make an initial identification of the main routes of emission to the environment or is the analysis aimed at providing a detailed basis for regulation of the use of the substance for specific applications? The influence of the different goals on the level of detail and reliability of the analysis is discussed further in chapter 3.

The goal and systems definitions are tightly connected. In the following is distinguished between what is designated the 'core SFA' and a number of optional extensions. The system definitions of the core SFA are the same for all SFAs covered by this paradigm, and is defined on the basis of the overall goal of the SFAs.

In the optional extensions the system boundaries in space and time is expanded as a consequence of some specific goals of the analysis. The overall goals of the extensions are defined for each extension in the detailed outline in Appendix 1.

System definition

The 'core SFA' of the present paradigm cover analysis of the total flow of a substance or a group of substances through the Danish society during one year. The system boundaries are discussed further in chapter 2.

SFAs may also provide input to Risk Assessments for chemical substances carried out according to EU regulation. A SFA is actually a basic part of the exposure assessment according to the EU Technical Guidance Document for Risk Assessments (TGD 1996). However, it should be emphasised that the system boundaries in both space and time of the SFAs used for the Risk Assessment are different from the boundaries of the SFAs covered by this paradigm.

The paradigm does not attempt to describe particular problems that may occur when carrying out other analyses e.g. national level MFAs or SFAs covering only parts of the Danish Society. A number of the comments provided would, however, also be applicable for such analyses.

Contents

The paradigm consists of a main report and Appendix 1. Appendix 1 contains the annotated outline for SFAs for substances at the national level and a description of a list of optional extensions of the analysis.

The main report should be seen as a general introduction to appendix 1 and to some extent to substance flow analysis in general. Furthermore, the main report attempts to draw up some general guidelines as to the level of detail and reliability of SFAs as well as for sources of information and their use. The manhour input required to carry out such analyses is summarised in Appendix 2.

Optional extensions

As mentioned above the paradigm covers what can be designated the 'core SFA' as defined by the boundaries described above and a list of optional extensions, which cover parts of the substance life cycle outside these system boundaries or other aspects in connection with the use of the substance.

The extensions expand the boundaries in space and time, but still the analysis is not expanded to include aspects regarding human toxicity, ecotoxicity and economic feasibility of substitution and legislative regulation. If these aspects are to be covered it is recommended to initiate a separate study.

The following optional extensions are included:

A: International market and trends in consumption, detailed analysis.

B: Qualitative description of the exposure of man by use and disposal of finished products

C: Scenarios for future emissions and loss of the substance

D: Occurrence and fate in the environment

E: National and international regulation on the use of the substance

F: Assessment of substitutes

G: Recycling, downcycling and material deterioration

The extensions A, B and partly F are recommended to be included into the main SFA report as outlined in appendix 1, whereas the other extensions are recommended to be prepared as appendixes to the report with short abstracts in the summary sections of the main report. The reason for this is to keep a common outline of the 'core SFAs' which make it easier to go across several SFAs and e.g. extract information on sources of heavy metals to solid waste incineration.

Focus areas

Beside extending the core SFA it may be relevant to focus the analysis on particular parts of the substance flow within the boundaries of the analysis. Within the focus area the analysis goes into more detail than determined by the overall level of detail and reliability (see next chapter).

The following focus areas should be considered before a SFA is initiated:

	Specific compounds within the substance group
	Chemical state of emitted compounds
	Consumption with marginal applications
	Parts of the life cycle - Consumption with finished goods - Disposal with solid waste - Emission from products in use - Danish production - specific compounds

A focus area can be the turnover of a specific chemical compound that only account for a minor part of the total turnover of the substance or substance group in question. In MFA for tin /Lassen & Hansen 1997/ the focus area was for example organotin compounds.

Chemical state of emitted compounds

For some substances the chemical state of emitted compounds may be of particular interest. For example, it may be of interest to know whether the chromium in residues from waste treatment is in a more or less oxidised state.

Marginal applications

For some analysis aimed at providing a basis for regulation of the substance the consumption of the substance with marginal applications may be a focus area. It means that additional input has to be allocated to the marginal applications although these applications only account for a very small part of the total turnover of the substance.

Parts of the life cycle

For some substances, parts of the life cycle may be of particular interest and more input may be allocated to these parts at the expense of other parts of the life cycle. For heavy metals the flows related to the treatment of solid waste may e.g. be of particular interest, whereas this part of the life cycle may be of less interest as regards volatile organic compounds

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