Index
of heavy metal emissions to air
TX-5
Dispersion
of Toxic Substances
Pressure
1 Indicator
definition and unit of measurement
Heavy
metals are the metals of environmental interest - e.g. mercury, cadmium, lead -
with few exceptions - e.g. aluminium. By giving them index, they can be handled
in clusters according to sources and emission patterns. Unit: tox.
equivalents/yr.
2 Placement
in the framework
5EAP:
Chapter
4: Selected target sectors, section 4.3: The transport sector.
Chapter
5: The themes and targets of the programme, section 5.2: Acidification and air
quality, table 8: Acidification, table 9: Air quality and section 5.4:
Management of water resources, table 11: Water quantity and water quality.
Agenda
21:
Chapter
17: Protection of the oceans, all kinds of seas, including enclosed and
semi-enclosed seas, and coastal areas and the protection, rational use and
development of their living resources.
Chapter
18: Protection of the quality and supply of freshwater resources: application
of integrated approaches to the development, management and use of water
resources.
Chapter
20: Environmentally-sound management of hazardous wastes, including prevention
of illegal international traffic in hazardous wastes (section D).
International
conventions and agreements:
Reductions
of emissions to waters are agreed upon in OSPARCOM (Oslo, 1972 and Paris,
1974), HELCOM (Helsinki, 1994) and the North Sea Ministerial Conference
(Esbjerg Declaration, 1995).
Ranking:
Core
ranking:
5
(26%)
Policy
Relevance:
6
(3.0)
Analytical
Soundness:
4
(3.0)
Responsiveness:
28
(2.3)
Most
appropriate related state indicator:
Amounts
of heavy metals in soil, water, sediments and sludge.
3 Significance
Purpose:
The
main purpose of this indicator is to represent the total amounts of heavy
metals emitted from different sources by different processes into air. Better
knowledge of emitted amounts helps activities aiming at decreasing emissions.
Relevance:
Metals
are totally persistent and all amounts emitted to air will after varying
residence time in the atmosphere be deposited on land or water and accumulate
in soil, water, sediments and, when applicable, sewage plant sludge. Many of
the heavy metals are toxic and an accumulation in these media is, consequently,
not sustainable.
Linkages
to other pressure indicators:
This
indicator is linked to TX-4: Index of heavy metal emissions to water, TX-7:
Emissions of heavy metals by consumption.
Targets:
Concerning
Acidification, the 5EAP calls for at least 70% reduction from all pathways of
Cd, Hg and Pb emissions in 1995; concerning Air quality, targets for heavy
metals are: - knowledge of existing levels, - different targets according to
the different existing situations (e.g. Cadmium: - knowledge of existing levels
and setting of norms, - compliance with norms for concentrations; for Lead: -
implementation and enforcement of existing legislation (through identification
of existing or potential problems and amendments to existing legislation).
4 Methodological
description and underlying definitions
Underlying
definitions and concepts:
Eight
heavy metals are in environmental focus
:
mercury, lead, cadmium, chromium, copper, arsenic, nickel and zinc. The first
three are used as indices due to different principle sources and strategies for
emission reduction. By focusing on these three, the rest of the heavy metals
will roughly be considered.
Measurement
methods:
Information
will be generated by emission inventories. Traffic, combustion processes will
be of large importance. A large part of the emissions from products containing
heavy metals will take place not only during production, but also during use
and as waste. Emitted amounts are estimated by the use of emission factors,
describing emission rates of substances from different media and uses.
Limitations
of the indicator:
Heavy
metals are a heterogeneous group of metals. Their inherent characteristics,
such as reactivity and toxic potential, differ. The relationship within the
cluster may vary from one location to another and from time to time. The
emission sources are often diffuse and the emission factors are in some cases
unreliable or non existing.
Alternative
definitions:
Emissions
of each of the three index-linked metals (mercury, lead, cadmium) are singled
out and measured separately, e.g. emissions of cadmium per year.
