TREATIES AND OTHER INTERNATIONAL ACTS SERIES 12966
Air Pollution on Heavy Metals
Protocol Between the
UNITED STATES OF AMERICA
and OTHER GOVERNMENTS
Done at Aarhus June 24, 1998
NOTE BY THE DEPARTMENT OF STATE
Pursuant to Public Law 89—497, approved July 8, 1966
(80 Stat. 271; 1 U.S.C. 113)—
“. . .the Treaties and Other International Acts Series issued
under the authority of the Secretary of State shall be competent
evidence . . . of the treaties, international agreements other than
treaties, and proclamations by the President of such treaties and
international agreements other than treaties, as the case may be,
therein contained, in all the courts of law and equity and of maritime
jurisdiction, and in all the tribunals and public offices of the
United States, and of the several States, without any further proof
or authentication thereof.”
Pollution: Long-Range Transboundary
Air Pollution on Heavy Metals
Protocol done at Aarhus June 24, 1998;
Entered into force December 29, 2003.
TO THE 1979 CONVENTION ON
AIR POLLUTION ON
TO THE 1979 CONVENTION ON LONG-RANGE TRANSBOUNDARY AIR POLLUTION
ON HEAVY METALS
Determined to implement the Convention on Long-range Transboundary Air
Concerned that emissions of certain heavy metals are transported across
national boundaries and may cause damage to ecosystems of environmental and
economic importance and may have harmful effects on human health,
Considering that combustion and industrial processes are the predominant
anthropogenic sources of emissions of heavy metals into the atmosphere,
Acknowledging that heavy metals are natural constituents of the Earth's
crust and that many heavy metals in certain forms and appropriate
concentrations are essential to life,
Taking into consideration existing scientific and technical data on the
emissions, geochemical processes, atmospheric transport and effects on human
health and the environment of heavy metals, as well as on abatement techniques
Aware that techniques and management practices are available to reduce
air pollution caused by the emissions of heavy metals,
Recognizing that countries in the region of the United Nations Economic
Commission for Europe (UN/ECE) have different economic conditions, and that in
certain countries the economies are in transition,
Resolved to take measures to anticipate, prevent or minimize emissions
of certain heavy metals and their related compounds, taking into account the
application of the precautionary approach, as set forth in principle 15 of the
Rio Declaration on Environment and Development,
Reaffirming that States have, in accordance with the Charter of the
United Nations and the principles of international law, the sovereign right to
exploit their own resources pursuant to their own environmental and
development policies, and the responsibility to ensure that activities within
their jurisdiction or control do not cause damage to the environment of Other
States or of areas beyond the limits of national jurisdiction,
Mindful that measures to control missions of heavy metals would also
contribute to the protection of the environment and human health in areas
outside the UN/ECE region, including the Arctic and international waters,
Noting that abating the emissions of specific heavy metals may provide
additional benefits for the abatement of emissions of other pollutants,
Aware that further and more effective action to control and reduce
emissions of certain heavy metals may be needed and that, for example,
effects-based studies may provide a basis for further action,
Noting the important contribution of the private and non-governmental
sectors to knowledge of the effects associated with heavy metals, available
alternatives and abatement techniques, and their role in assisting in the
reduction of emissions of heavy metals,
Bearing in mind the activities related to the control of heavy metals at
the national level and in international forums,
Have agreed as follows :
For the purposes of the present Protocol,
1. "Convention" means the Convention on Long-range Transboundary Air
Pollution, adopted in Geneva on 13 November 1979;
2. "BMW" means the Cooperative Programme for Monitoring and Evaluation of
Long-range Transmission of Air Pollutants in Europe
3. "Executive Body" means the Executive Body for the Convention constituted
under article 10, paragraph 1, of the Convention;
4. "Commission" means the United Nations Economic Commission for Europe;5
. "Parties" means, unless the context otherwise requires, the Parties to
the present Protocol;
6. "Geographical scope of EMEP" means the area defined in article 1,
paragraph 4, of the Protocol to the 1979 Convention on Long-range
Transboundary Air Pollution on Long-term Financing of the Cooperative
Programme for Monitoring and Evaluation of the Long-range Transmission of Air
Pollutants in Europe (EMEP), adopted in Geneva on 28 September 1984;
7. "Heavy metals" means those metals or, in some cases, metalloids which
are stable and have a density greater than 4.5 g/cm3 and their compounds;
8. "Emission" means a release from a point or diffuse source into the
9. "Stationary source" means any fixed building, structure, facility,
installation, or equipment that emits or may emit a heavy metal listed in
annex I directly or indirectly into the atmosphere;
10. "New stationary source" means any stationary source of which the
construction or substantial modification is commenced after the expiry of two
years from the date of entry into force of: (i) this Protocol; or (ii) an
amendment to annex I or II, where the stationary source becomes subject to the
provisions of this Protocol only by virtue of that amendment. It shall be a
matter for the competent national authorities to decide whether a modification
is substantial or not, taking into account such factors as the environmental
benefits of the modification;
11. "Major stationary source category" means any stationary source category
that is listed in annex II and that contributes at least one per cent to a
Party's total emissions from stationary sources of a heavy metal listed in
annex I for the reference year specified in accordance with annex I.
The objective of the present Protocol is to control emissions of heavy
metals caused by anthropogenic activities that are subject to long-range
transboundary atmospheric transport and are likely to have significant adverse
effects on human health or the environment, in accordance with the provisions
of the following articles.
1. Each Party shall reduce its total annual emissions into the atmosphere
of each of the heavy metals listed in annex I from the level of the emission
in the reference year set in accordance with that annex by taking effective
measures, appropriate to its particular circumstances.
2. Each Party shall, no later than the timescales specified in annex IV,
(a) The best available techniques, taking into consideration
annex III, to each new stationary source within a major stationary source
category for which annex III identifies best available techniques;
(b) The limit values specified in annex V to each new stationary
source within a major stationary source category. A Party may, as an
alternative, apply different emission reduction strategies that achieve
equivalent overall emission levels;
(c) The best available techniques, taking into consideration
annex III, to each existing stationary source within a major stationary source
category for which annex III identifies best available techniques. A Party
may, as an alternative, apply different emission reduction strategies that
achieve equivalent overall emission reductions;
(d) The limit values specified in annex V to each existing stationary
source within a major stationary source category, insofar as this is
technically and economically feasible. A Party may, as an alternative, apply
different emission reduction strategies that achieve equivalent overall
3. Each Party shall apply product control measures in accordance with the
conditions and timescales specified in annex VI.
4. Each Party should consider applying additional product management
measures, taking into consideration annex VIZ.
5. Each Party shall develop and maintain emission inventories for the heavy
metals listed in annex I, for those Parties within the geographical scope of
EMEP, using as a minimum the methodologies specified by the Steering Body of
EMEP, and, for those Parties outside the geographical scope of EMEP, using as
guidance the methodologies developed through the work plan of the Executive
6. A Party that, after applying paragraphs 2 and 3 above, cannot achieve
the requirements of paragraph 1 above for a heavy metal listed in annex I,
shall be exempted from its obligations in paragraph 1 above for that heavy
7. Any Party whose total land area is greater than 6,000,000 km2 shall be
exempted from its obligations in paragraphs 2 (b), (c), and (d) above, if it
can demonstrate that, no later than eight years after the date of entry into
force of the present Protocol, it will have reduced its total annual emissions
of each of the heavy metals listed in annex I from the source categories
specified in annex II by at least 50 per cent from the level of emissions from
these categories in the reference year specified in accordance with annex I.
A Party that intends to act in accordance with this paragraph shall so specify
upon signature of, or accession to, the present Protocol.
EXCHANGE OF INFORMATION AND TECHNOLOGY
1. The Parties shall, in a manner consistent with their laws, regulations
and practices, facilitate the exchange of technologies and techniques designed
to reduce emissions of heavy metals, including but not limited to exchanges
that encourage the development of product management measures and the
application of best available techniques, in particular by promoting:
(a) The commercial exchange of available technology;
(b) Direct industrial contacts and cooperation, including joint
(c) The exchange of information and experience; and
(d) The provision of technical assistance.
2. In promoting the activities specified in paragraph 1 above, the Parties
shall create favourable conditions by facilitating contacts and cooperation
among appropriate organizations and individuals in the private and public
sectors that are capable of providing technology, design and engineering
services, equipment or finance.
STRATEGIES, POLICIES, PROGRAMMES AND MEASURES
1. Each Party shall develop, without undue delay, strategies, policies and
programmes to discharge its obligations under the present Protocol.
2. A Party may, in addition:
(a) Apply economic instruments to encourage the adoption of
cost-effective approaches to the reduction of heavy metal emissions;
(b) Develop government/industry covenants and voluntary agreements;
(c) Encourage the more efficient use of resources and raw materials;
(d) Encourage the use of less polluting energy sources;
(e) Take measures to develop and introduce less polluting transport
(f) Take measures to phase out certain heavy metal emitting processes
where substitute processes are available on an industrial scale;
(g) Take measures to develop and employ cleaner processes for the
prevention and control of pollution.
3. The Parties may take more stringent measures than those required by the
RESEARCH, DEVELOPMENT AND MONITORING
The Parties shall encourage research, development, monitoring and
cooperation, primarily focusing on the heavy metals listed in annex I,
related, but not limited, to:
(a) Emissions, long-range transport and deposition levels and their
modelling, existing levels in the biotic and abiotic environment, the
formulation of procedures for harmonizing relevant methodologies;
(b) Pollutant pathways and inventories in representative ecosystems;
(c) Relevant effects on human health and the environment, including
quantification of those effects;
(d) Best available techniques and practices and emission control
techniques currently employed by the Parties or under development;
(e) Collection, recycling and, if necessary, disposal of products or
wastes containing one or more heavy metals;
(f) Methodologies permitting consideration of socio-economic factors
in the evaluation of alternative control strategies;
(g) An effects-based approach which integrates appropriate
information, including information obtained under subparagraphs (a) to (f)
above, on measured or modelled environmental levels, pathways, and effects on
human health and the environment, for the purpose of formulating future
optimized control strategies which also take into account economic and
(h) Alternatives to the use of heavy metals in products listed in
annexes VI and VII;
(i) Gathering information on levels of heavy metals in certain
products, on the potential for emissions of those metals to occur during the
manufacture, processing, distribution in commerce, use, and disposal of the
product, and on techniques to reduce such emissions.
1. Subject to its laws governing the confidentiality of commercial
(a) Each Party shall report, through the Executive Secretary of the
Commission, to the Executive Body, on a periodic basis as determined by the
Parties meeting within the Executive Body, information on the measures that it
has taken to implement the present Protocol;
(b) Each Party within the geographical scope of EMEP shall report,
through the Executive Secretary of the Commission, to EMEP, on a periodic
basis to be determined by the Steering Body of EMEP and approved by the
Parties at a session of the Executive Body, information on the levels of
emissions of the heavy metals listed in annex I, using as a minimum the
methodologies and the temporal and spatial resolution specified by the
Steering Body of EMEP. Parties in areas outside the geographical scope of
EMEP shall make available similar information to the Executive Body if
requested to do so. In addition, each Party shall, as appropriate, collect
and report relevant information relating to its emissions of other heavy
metals, taking into account the guidance on the methodologies and the temporal
and spatial resolution of the Steering Body of EMEP and the Executive Body.
2. The information to be reported in accordance with paragraph 1 (a) above
shall be in conformity with a decision regarding format and content to be
adopted by the Parties at a session of the Executive Body. The terms of this
decision shall be reviewed as necessary to identify any additional elements
regarding the format or the content of the information that is to be included
in the reports.
3. In good time before each annual session of the Executive Body, EMEP
shall provide information on the long-range transport and deposition of heavy
EMEP shall, using appropriate models and measurements and in good time
before each annual session of the Executive Body, provide to the Executive
Body calculations of transboundary fluxes and depositions of heavy metals
within the geographical scope of EMEP. In areas outside the geographical
scope of EMEP, models appropriate to the particular circumstances of Parties
to the Convention shall be used.
Compliance by each Party with its obligations under the present Protocol
shall be reviewed regularly. The Implementation Committee established by
decision 1997/2 of the Executive Body at its fifteenth session shall carry out
such reviews and report to the Parties meeting within the Executive Body in
accordance with the terms of the annex to that decision, including any
REVIEWS BY THE PARTIES AT SESSIONS OF THE EXECUTIVE BODY
1. The Parties shall, at sessions of the Executive Body, pursuant to
article 10, paragraph 2 (a), of the Convention, review the information
supplied by the Parties, EMEP and other subsidiary bodies and the reports of
the Implementation Committee referred to in article 9 of the present Protocol.
2. The Parties shall, at sessions of the Executive Body, keep under review
the progress made towards meeting the obligations set out in the present
3. The Parties shall, at sessions of the Executive Body, review the
sufficiency and effectiveness of the obligations set out in the present
(a) Such reviews will take into account the best available scientific
information on the effects of the deposition of heavy metals, assessments of
technological developments, and changing economic conditions;
(b) Such reviews will, in the light of the research, development,
monitoring and cooperation undertaken under the present Protocol :
(i) Evaluate progress towards meeting the objective of the
(ii) Evaluate whether additional emission reductions beyond the
levels required by this Protocol are warranted to reduce
further the adverse effects on human health or the
(iii) Take into account the extent to which a satisfactory basis
exists for the application of an effects-based approach;
(c) The procedures, methods and timing for such reviews shall be
specified by the Parties at a session of the Executive Body.
4. The Parties shall, based on the conclusion of the reviews referred to in
paragraph 3 above and as soon as practicable after completion of the review,
develop a work plan on further steps to reduce emissions into the atmosphere
of the heavy metals listed in annex I.
SETTLEMENT OF DISPUTES
1. In the event of a dispute between any two or more Parties concerning the
interpretation or application of the present Protocol, the Parties concerned
shall seek a settlement of the dispute through negotiation or any other
peaceful means of their own choice. The Parties to the dispute shall inform
the Executive Body of their dispute.
2. When ratifying, accepting, approving or acceding to the present
Protocol, or at any time thereafter, a Party which is not a regional economic
integration organization may declare in a written instrument submitted to the
Depositary that, in respect of any dispute concerning the interpretation or
application of the Protocol, it recognizes one or both of the following means
of dispute settlement as compulsory ipso facto and without special agreement,
in relation to any Party accepting the same obligation:
(a) Submission of the dispute to the International Court of Justice;
(b) Arbitration in accordance with procedures to be adopted by the
Parties at a session of the Executive Body, as soon as practicable, in an
annex on arbitration.
A Party which is a regional economic integration organization may make a
declaration with like effect in relation to arbitration in accordance with the
procedures referred to in subparagraph (b) above.
3. A declaration made under paragraph 2 above shall remain in force until
it expires in accordance with its terms or until three months after written
notice of its revocation has been deposited with the Depositary.
4. A new declaration, a notice of revocation or the expiry of a declaration
shall not in any way affect proceedings pending before the International Court
of Justice or the arbitral tribunal, unless the Parties to the dispute agree
5. Except in a case where the Parties to a dispute have accepted the same
means of dispute settlement under paragraph 2, if after twelve months
following notification by one Party to another that a dispute exists between
them, the Parties concerned have not been able to settle their dispute through
the means mentioned in paragraph 1 above, the dispute shall be submitted, at
the request of any of the Parties to the dispute, to conciliation.
6. For the purpose of paragraph 5, a conciliation commission shall be
created. The commission shall be composed of equal numbers of members
appointed by each Party concerned or, where the Parties in conciliation share
the same interest, by the group sharing that interest, and a chairman chosen
jointly by the members so appointed. The commission shall render a
recommendatory award, which the Parties shall consider in good faith.
The annexes to the present Protocol shall form an integral part of the
Protocol. Annexes III and VII are recommendatory in character.
AMENDMENTS TO THE PROTOCOL
1. Any Party may propose amendments to the present Protocol.
2. Proposed amendments shall be submitted in writing to the Executive
Secretary of the Commission, who shall communicate them to all Parties. The
Parties meeting within the Executive Body shall discuss the proposed
amendments at its next session, provided that the proposals have been
circulated by the Executive Secretary to the Parties at least ninety days in advance.
3. Amendments to the present Protocol and to annexes I, II, IV, V and VI
shall be adopted by consensus of the Parties present at a session of the
Executive Body, and shall enter into force for the Parties which have accepted
them on the ninetieth day after the date on which two thirds of the Parties
have deposited with the Depositary their instruments of acceptance thereof.
Amendments shall enter into force for any other Party on the ninetieth day
after the date on which that Party has deposited its instrument of acceptance
4. Amendments to annexes III and VII shall be adopted by consensus of the
Parties present at a session of the Executive Body. On the expiry of ninety
days from the date of its communication to all Parties by the Executive
Secretary of the Commission, an amendment to any such annex shall become
effective for those Parties which have not submitted to the Depositary a
notification in accordance with the provisions of paragraph 5 below, provided
that at least sixteen Parties have not submitted such a notification.
5. Any Party that is unable to approve an amendment to annex III or VII
shall so notify the Depositary in writing within ninety days from the date of
the communication of its adoption. The Depositary shall without delay notify
all Parties of any such notification received. A Party may at any time
substitute an acceptance for its previous notification and, upon deposit of an
instrument of acceptance with the Depositary, the amendment to such an annex
shall become effective for that Party.
6. In the case of a proposal to amend annex I, VI or VII by adding a heavy
metal, a product control measure or a product or product group to the present
Protocol: - 8 -
(a) The proposer shall provide the Executive Body with the information
specified in Executive Body decision 1998/1, including any amendments thereto;
(b) The Parties shall evaluate the proposal in accordance with the
procedures set forth in Executive Body decision 1998/1, including any
7. Any decision to amend Executive Body decision 1998/1 shall be taken by
consensus of the Parties meeting within the Executive Body and shall take
effect sixty days after the date of adoption.
1. The present Protocol shall be open for signature at Aarhus (Denmark)
from 24 to 25 June 1998, then at United Nations Headquarters in New York until
21 December 1998 by States members of the Commission as well as States having
consultative status with the Commission pursuant to paragraph 8 of Economic
and Social Council resolution 36 (IV) of 28 March 1947, and by regional
economic integration organizations, constituted by sovereign States members of
the Commission, which have competence in respect of the negotiation,
conclusion and application of international agreements in matters covered by
the Protocol, provided that the States and organizations concerned are Parties
to the Convention.
2. In matters within their competence, such regional economic integration
organizations shall, on their own behalf, exercise the rights and fulfil the
responsibilities which the present Protocol attributes to their member States.
In such cases, the member States of these organizations shall not be entitled
to exercise such rights individually.
RATIFICATION, ACCEPTANCE, APPROVAL AND ACCESSION
1. The present Protocol shall be subject to ratification, acceptance or
approval by Signatories.
2. The present Protocol shall be open for accession as from
21 December 1998 by the States and organizations that meet the requirements of
article 14, paragraph 1.
The instruments of ratification, acceptance, approval or accession shall
be deposited with the Secretary-General of the United Nations, who will
perform the functions of Depositary.
ENTRY INTO FORCE
1. The present Protocol shall enter into force on the ninetieth day
following the date on which the sixteenth instrument of ratification,
acceptance, approval or accession has been deposited with the Depositary.
2. For each State and organization referred to in article 14, paragraph 1,
which ratifies, accepts or approves the present Protocol or accedes thereto
after the deposit of the sixteenth instrument of ratification, acceptance,
approval or accession, the Protocol shall enter into force on the ninetieth
day following the date of deposit by such Party of its instrument of
ratification, acceptance, approval or accession.
At any time after five years from the date on which the present Protocol
has come into force with respect to a Party, that Party may withdraw from it
by giving written notification to the Depositary. Any such withdrawal shall
take effect on the ninetieth day following the date of its receipt by the
Depositary, or on such later date as may be specified in the notification of
The original of the present Protocol, of which the English, French and
Russian texts are equally authentic, shall be deposited with the
Secretary-General of the United Nations.
IN WITNESS WHEREOF the undersigned, being duly authorized thereto, have
signed the present Protocol.
Done at Aarhus (Denmark), this twenty-fourth day of June, one thousand
nine hundred and ninety-eight.
NOTE: Only English text will be printed in this publication.
HEAVY METALS REFERRED TO IN ARTICLE 3, PARAGRAPH 1,
AND THE REFERENCE YEAR FOR THE OBLIGATION
Cadmium (Cd) 1990; or an alternative year from 1985 to 1995
inclusive, specified by a Party upon ratification,
acceptance, approval or accession.
Lead (Pb) 1990; or an alternative year from 1985 to 1995
inclusive, specified by a Party upon ratification,
acceptance, approval or accession.
Mercury (Hg) 1990; or an alternative year from 1985 to 1995
inclusive, specified by a Party upon ratification,
acceptance, approval or accession.
STATIONARY SOURCE CATEGORIES
1. Installations or parts of installations for research, development and
the testing of new products and processes are not covered by this annex.
2. The threshold values given below generally refer to production
capacities or output. Where one operator carries out several activities
falling under the same subheading at the same installation or the same site,
the capacities of such activities are added together.
II. LIST OF CATEGORIES
Category Description of the category
1 ombustion installations with a net rated thermal input exceeding
2 Metal ore (including sulphide ore) or concentrate roasting or
sintering installations with a capacity exceeding 150 tonnes of
sinter per day for ferrous ore or concentrate, and 30 tonnes of
sinter per day for the roasting of copper, lead or zinc, or any gold
. d mercury ore treatment.
3 Installations for the production of pig-iron or steel (primary or
secondary fusion, including electric arc furnaces) including
continuous casting, with a capacity exceeding 2.5 tonnes per hour.
4 errous metal foundries with a production capacity exceeding
20 tonnes per day.
5 Installations for the production of copper, lead and zinc from ore,
concentrates or secondary raw materials by metallurgical processes
ith a capacity exceeding 30 tonnes of metal per day for primary
installations and 15 tonnes of metal per day for secondary
installations, or for any primary production of mercury.
6 Installations for the smelting (refining, foundry casting, etc.),
including the alloying, of copper, lead and zinc, including recovered
products, with a melting capacity exceeding 4 tonnes per day for lead
or 20 tonnes per day for copper and zinc.
7 Installations for the production of cement clinker in rotary kilns
ith a production capacity exceeding 500 tonnes per day or in other
furnaces with a production capacity exceeding 50 tonnes per day.
8 Installations for the manufacture of glass using lead in the process
ith a melting capacity exceeding 20 tonnes per day.
9 Installations for chlor-alkali production by electrolysis using the
ercury cell process.
10 Installations for the incineration of hazardous or medical waste with
. capacity exceeding 1 tonne per hour, or for the co-incineration of
hazardous or medical waste specified in accordance with national
11 Installations for the incineration of municipal waste with a capacity
-exceeding 3 tonnes per hour, or for the co-incineration of municipal
aste specified in accordance with national legislation.
BEST AVAILABLE TECHNIQUES FOR CONTROLLING EMISSIONS
OF HEAVY METALS AND THEIR COMPOUNDS FROM THE SOURCE
CATEGORIES LISTED IN ANNEX II
1. This annex aims to provide Parties with guidance on identifying best
available techniques for stationary sources to enable them to meet the
obligations of the Protocol.
2. "Best available techniques" (BAT) means the most effective and advanced
stage in .the development of activities and their methods of operation which
indicate the practical suitability of particular techniques for providing in
principle the basis for emission limit values designed to prevent and, where
that is not practicable, generally to reduce emissions and their impact on the
environment as a whole:
"Techniques" includes both the technology used and the way in
which the installation is designed, built, maintained, operated
"Available" techniques means those developed on a scale which
allows implementation in the relevant industrial sector, under
economically and technically viable conditions, taking into
consideration the costs and advantages, whether or not the
techniques are used or produced inside the territory of the Party
in question, as long as they are reasonably accessible to the
• "Best" means most effective in achieving a high general level of
protection of the environment as a whole.
In determining the best available techniques, special consideration should be
given, generally or in specific cases, to the factors below, bearing in mind
the likely costs and benefits of a measure and the principles of precaution
The use of low-waste technology;
• The use of less hazardous substances;
The furthering of recovery and recycling of substances generated
and used in the process and of waste;
Comparable processes, facilities or methods of operation which
have been tried with success on an industrial scale;
Technological advances and changes in scientific knowledge and
The nature, effects and volume of the emissions concerned;
^ The commissioning dates for new or existing installations;
The time needed to introduce the best available technique;
The consumption and nature of raw materials (including water) used
in the process and its energy efficiency;
The need to prevent or reduce to a minimum the overall impact of
the emissions on the environment and the risks to it;
• The need to prevent accidents and to minimize their consequences
for the environment.
The concept of best available techniques is not aimed at the prescription of
any specific technique or technology, but at taking into account the technical
characteristics of the installation concerned, its geographical location and
the local environmental conditions.
3 . The information regarding emission control performance and costs is
based on official documentation of the Executive Body and its subsidiary
bodies, in particular documents received and reviewed by the Task Force on
Heavy Metal Emissions and the Ad Hoc Preparatory Working Group on Heavy
Metals. Furthermore, other international information on best available
techniques for emission control has been taken into consideration (e.g. the
European Community's technical notes on BAT, the PARCOM recommendations for
BAT, and information provided directly by experts).
4. Experience with new products and new plants incorporating low-emission
techniques, as well as with the retrofitting of existing plants, is growing
continuously; this annex may, therefore, need amending and updating.
5. The annex lists a number of measures spanning a range of costs and
efficiencies. The choice of measures for any particular case will depend on,
and may be limited by, a number of factors, such as economic circumstances,
technological infrastructure, any existing emission control device, safety,
energy consumption and whether the source is a new or existing one.
6. This annex takes into account the emissions of cadmium, lead and mercury
and their compounds, in solid (particle-bound) and/or gaseous form.
Speciation of these compounds is, in general, not considered here.
Nevertheless, the efficiency of emission control devices with regard to the
physical properties of the heavy metal, especially in the case of mercury, has
been taken into account.
7. Emission values expressed as mg/m3 refer to standard conditions (volume
at 273.15 101.3 kPa, dry gas) not corrected for oxygen content unless
otherwise specified, and are calculated in accordance with draft CEN (Comite
européen de normalisation) and, in some cases, national sampling and
II. GENERAL OPTIONS FOR REDUCING EMISSIONS OF HEAVY METALS AND THEIR
8. There are several possibilities for controlling or preventing heavy
metal emissions. Emission reduction measures focus on add-on technologies and
process modifications (including maintenance and operating control). The
following measures, which may be implemented depending on the wider technical
and/or economic conditions, are available:
(a) Application of low-emission process technologies, in particular in
(b) Off-gas cleaning (secondary reduction measures) with filters,
scrubbers, absorbers, etc.;
(c) Change or preparation of raw materials, fuels and/or other feed
materials (e.g. use of raw materials with low heavy metal content);
(d) Best management practices such as good housekeeping, preventive
maintenance programmes, or primary measures such as the enclosure of
(e) Appropriate environmental management techniques for the use and
disposal of certain products containing Cd, Pb, and/or Hg.
9. It is necessary to monitor abatement procedures to ensure that
appropriate control measures and practices are properly implemented and
achieve an effective emission reduction. Monitoring abatement procedures will
(a) Developing an inventory of those reduction measures identified
above that have already been implemented;
(b) Comparing actual reductions in Cd, Pb and Hg emissions with the
objectives of the Protocol;
(c) Characterizing quantified emissions of Cd, Pb and Hg from relevant
sources with appropriate techniques;
(d) Regulatory authorities periodically auditing abatement measures to
ensure their continued efficient operation.
10. Emission reduction measures should be cost-efficient. Cost-efficient
strategy considerations should be based on total costs per year per unit
abated (including capital and operating costs). Emission reduction costs
should also be considered with respect to the overall process.
III. CONTROL TECHNIQUES
11. The major categories of available control techniques for Cd, Pb and Hg
emission abatement are primary measures such as raw material and/or fuel
substitution and low-emission process technologies, and secondary measures
such as fugitive emission control and off-gas cleaning. Sector-specific
techniques are specified in chapter IV.
12. The data on efficiency are derived from operating experience and are
considered to reflect the capabilities of current installations. The overall
efficiency of flue gas and fugitive emission reductions depends to a great
extent on the evacuation performance of the gas and dust collectors (e.g.
suction hoods). Capture/collection efficiencies of over 99 per cent have been
demonstrated. In particular cases experience has shown that control measures
are able to reduce overall emissions by 90 per cent or more.
13. In the case of particle-bound emissions of Cd, Pb and Hg, the metals can
be captured by dust-cleaning devices. Typical dust concentrations after gas
cleaning with selected techniques are given in table 1. Most of these
measures have generally been applied across sectors. The minimum expected
performance of selected techniques for capturing gaseous mercury is outlined
in table 2. The application of these measures depends on the specific
processes and is most relevant if concentrations of mercury in the flue gas
Table 1: Performance of dust-cleaning devices expressed as hourly average
Dust concentrations after cleaning (mg/m3)'
Fabric filters < 10
Fabric filters, membrane type < 1
Dry electrostatic precipitators < 50
Wet electrostatic precipitators < 50
High-efficiency scrubbers < 50
Note: Medium- and low-pressure scrubbers and cyclones generally show
lower dust removal efficiencies.
Table 2: Minimum expected performance of mercury separators expressed as
hourly average mercury concentrations
Mercury content after cleaning (mg/m3)
Selenium filter < 0.01
Selenium scrubber < 0.2
Carbon filter < 0.01
Carbon injection + dust separator < 0.05
Odda Nor z ink chloride process < 0.1
Lead sulphide process < 0.05
Bolkem (Thiosulphate) process < 0.1
14. Care should be taken to ensure that these control techniques do not
create other environmental problems. The choice of a specific process because
of its low emission into the air should be avoided if it worsens the total
environmental impact of the heavy metals' discharge, e.g. due to more water
pollution from liquid effluents. The fate of captured dust resulting from
improved gas cleaning must also be taken into consideration. A negative
environmental impact from the handling of such wastes will reduce the gain
from lower process dust and fume emissions into the air.
15. Emission reduction measures can focus on process techniques as well as
on off-gas cleaning. The two are not independent of each other; the choice
of a specific process might exclude some gas-cleaning methods.
16. The choice of a control technique will depend on such parameters as the
pollutant concentration and/or speciation in the raw gas, the gas volume flow,
the gas temperature, and others. Therefore, the fields of application may
overlap; in that case, the most appropriate technique must be selected
according to case-specific conditions.
17. Adequate measures to reduce stack gas emissions in various sectors are
described below. Fugitive emissions have to be taken into account. Dust
emission control associated with the discharging, handling, and stockpiling of
raw materials or by-products, although not relevant to long-range transport,
may be important for the local environment. The emissions can be reduced by
moving these activities to completely enclosed buildings, which may be
equipped with ventilation and deducting facilities, spray systems or other
suitable controls. When stockpiling in unroofed areas, the material surface
should be otherwise protected against wind entrainment. Stockpiling areas and
roads should be kept clean.
18. The investment/cost figures listed in the tables have been collected
from various sources and are highly case-specific. They are expressed in 1990
US$ (US$ 1 (1990) = ECU 0.8 (1990)). They depend on such factors as plant
capacity, removal efficiency and raw gas concentration, type of technology,
and the choice of new installations as opposed to retrofitting.
19. This chapter contains a table per relevant sector with the main emission
sources, control measures based on the best available techniques, their
specific reduction efficiency and the related costs, where available. Unless
stated otherwise, the reduction efficiencies in the tables refer to direct
stack gas emissions. -16-
Combustion of fossil fuels in utility and industrial boilers (annex II,
20. The combustion of coal in utility and industrial boilers is a major
source of anthropogenic mercury emissions. The heavy metal content is
normally several orders of magnitude higher in coal than in oil or natural
21. Improved energy conversion efficiency and energy conservation measures
will result in a decline in the emissions of heavy metals because of reduced
fuel requirements. Combusting natural gas or alternative fuels with a low
heavy metal content instead of coal would also result in a significant
reduction in heavy metal emissions such as mercury. Integrated gasification
combined-cycle (IGCC) power plant technology is a new plant technology with a
22. With the exception of mercury, heavy metals are emitted in solid form in
association with fly-ash particles. Different coal combustion technologies
show different magnitudes of fly-ash generation: grate-firing boilers 20-40%;
fluidized-bed combustion 15%; dry bottom boilers (pulverized coal combustion)
70-100% of total ash. The heavy metal content in the small particle size
fraction of the fly-ash has been found to be higher.
23. Beneficiation, e.g. "washing" or "bio-treatment", of coal reduces the
heavy metal content associated with the inorganic matter in the coal.
However, the degree of heavy metal removal with this technology varies widely.
24. A total dust removal of more than 99.5% can be obtained with
electrostatic precipitators (ESP) or fabric filters (FF), achieving dust
concentrations of about 20 mg/m3 in many cases. With the exception of
mercury, heavy metal emissions can be reduced by at least 90-99%, the lower
figure for the more easily volatilized elements. Low filter temperature helps
to reduce the gaseous mercury off-gas content.
25. The application of techniques to reduce emissions of nitrogen oxides,
sulphur dioxide and particulates from the flue gas can also remove heavy
metals. Possible cross media impact should be avoided by appropriate waste
26. Using the techniques mentioned above, mercury removal efficiencies vary
extensively from plant to plant, as seen in table 3. Research is ongoing to
develop mercury removal techniques, but until such techniques are available on
an industrial scale, no best available technique is identified for the
specific purpose of removing mercury. -17-
Table 3: Control measures, reduction efficiencies and costs for fossil-fuel
Emission source Control measure (s) Reduction efficiency (%) Abatement costs
Combustion of Switch fran fuel oil Cd, Pb: 100; Highly
fuel oil to gas Hg: 70 - 80 case-specific
Combustion of Switch from coal to Dust: 70 - 100 Highly
coal fuels with lower heavy case-specific
ESP (cold-side) Cd, Pb: > 90; Specific
Hg: 10 - 40 investment
US$ 5-10/m3 waste
gas per hour
(> 200,000 m3/h)
Wet flue-gas desul- Cd, Pb: > 90; ..
phurization (FGD) a/ Hg: 10 - 90 b/
Fabric filters 01 Cd: > 95; Pb: > 99; Specific
Hg: 10 - 60 investment
US$ 8-15/m3 waste
gas per hour
(> 200,000 m3/h)
a/ Hg removal efficiencies increase with the proportion of ionic
mercury. High-dust selective catalytic reduction (SCR) installations
facilitate Hg(II) formation.
b/ This is primarily for SO2 reduction. Reduction in heavy metal
emissions is a side benefit. (Specific investment US$ 60-250/kWel.)
Primary iron and steel industry (annex II, category 2)
27. This section deals with emissions from sinter plants, pellet plants,
blast furnaces, and steelworks with a basic oxygen furnace (BOF). Emissions
of Cd, Pb and Hg occur in association with particulates. The content of the
heavy metals of concern in the emitted dust depends on the composition of the
raw materials and the types of alloying metals added in steel-making. The
most relevant emission reduction measures are outlined in table 4. Fabric
filters should be used whenever possible; if conditions make this impossible,
electrostatic precipitators and/or high-efficiency scrubbers may be used.
28. When using BAT in the primary iron and steel industry, the total
specific emission of dust directly related to the process can be reduced to
the following levels:
Sinter plants 40 - 120 g/Mg
Pellet plants 40 g/Mg
Blast furnace 35 - 50 g/Mg
BOF 35 - 70 g/Mg.
29. Purification of gases using fabric filters will reduce the dust content
to less than 20 mg/m3, whereas electrostatic precipitators and scrubbers will
reduce the dust content to 50 mg/m3 (as an hourly average). However, there
are many applications of fabric filters in the primary iron and steel industry
that can achieve much lower values. -18-
Table 4: Emission sources, control measures, dust reduction efficiencies
and costs for the primary iron and steel industry
Emission Control measure (s) Dust reduction Abatement costs
source efficiency (%) (total costs US$)
Sinter plants Emission optimized ca. 50 ..
Scrubbers and ESP > 90
Fabric filters > 99 ..
Pellet plants ESP + lime reactor + > 99 . .
Scrubbers > 95 ..
Blast furnaces > 99 ESP: 0.24-1/Mg pig-iron
FF / ESP
Blast furnace Wet scrubbers > 99 ..
gas cleaning wet ESP > 99 . .
BOF Primary dedusting: wet > 99 Dry ESP: 2.25/Mg steel
Secondary dedusting: dry > 97 FF: 0.26/Mg steel
Fugitive Closed conveyor belts, 80 - 99 ..
emissions enclosure, wetting
cleaning of roads
30. Direct reduction and direct smelting are under
development and may
reduce the need for sinter plants and blast furnaces
in the future. The
application of these technologies depends on the ore
requires the resulting product to be processed in an
electric arc furnace,
which should be equipped with appropriate controls.
Secondary iron and steel industry (annex II, category 3)
31. It is very important to capture all the emissions efficiently. That is
possible by installing doghouses or movable hoods or by total building
evacuation. The captured emissions must be cleaned. For all dust-emitting
processes in the secondary iron and steel industry, dedusting in fabric
filters, which reduces the dust content to less than 20 mg/m3, shall be
considered as BAT. When BAT is used also for minimizing fugitive emissions,
the specific dust emission (including fugitive emission directly related to
the process) will not exceed the range of 0.1 to 0.35 kg/Mg steel. There are
many examples of clean gas dust content below 10 mg/m3 when fabric filters are
used. The specific dust emission in such cases is normally below 0.1 kg/Mg.
32. For the melting of scrap, two different types of furnace are in use:
open-hearth furnaces and electric arc furnaces (EAF) where open-hearth
furnaces are about to be phased out.
33. The content of the heavy metals of concern in the emitted dust depends
on the composition of the iron and steel scrap and the types of alloying
metals added in steel-making. Measurements at EAF have shown that 95% of
emitted mercury and 25% of cadmium emissions occur as vapour. The most
relevant dust emission reduction measures are outlined in table 5. -19-
Table 5: Emission sources, control measures, dust reduction efficiencies
and costs for the secondary iron and steel industry
Emission source Control measure (a) Dust reduction Abatement costs efficiency (%) (total costs US$)
EAF ESP > 99 ..
FF > 99.5 FF: 24/Mg steel
Iron foundries (annex II, category 4)
34. It is very important to capture all the emissions efficiently. That is
possible by installing doghouses or movable hoods or by total building
evacuation. The captured emissions must be cleaned. In iron foundries,
cupola furnaces, electric arc furnaces and induction furnaces are operated.
Direct particulate and gaseous heavy metal emissions are especially associated
with melting and sometimes, to a small extent, with pouring. Fugitive
emissions arise from raw material handling, melting, pouring and fettling.
The most relevant emission reduction measures are outlined in table 6 with
their achievable reduction efficiencies and costs, where available. These
measures can reduce dust concentrations to 20 mg/m3, or less.
35. The iron foundry industry comprises a very wide range of process sites.
For existing smaller installations, the measures listed may not be BAT if they
are not economically viable.
Table 6: Emission sources, control measures, dust reduction efficiencies
and costs for iron foundries
Emission source Control measure (s) Dust reduction Abatement costs efficiency % (total costs US$)
EAF ESP > 99 .. FF > 99.5 FF: 24/Mg iron
Induction furnace FF/dry absorption + FF > 99 ..
Cold blast cupola Below-the-door take-off: FF > 98 ..
Above-the-door take-off: FF + pre-dedusting > 97 8-12/Mg iron
FF + chemisorption > 99 45/Mg iron
Hot blast cupola FF + pre-dedusting > 99 23/Mg iron
venturi scrubber > 97 ..
Primary and secondary non-ferrous metal industry (annex II, categories 5
36. This section deals with emissions and emission control of Cd, Pb and Hg
in the primary and secondary production of non-ferrous metals like lead,
copper, zinc, tin and nickel. Due to the large number of different raw
materials used and the various processes applied, nearly all kinds of heavy
metals and heavy metal compounds might be emitted from this sector. Given the
heavy metals of concern in this annex, the production of copper, lead and zinc
are particularly relevant.
37. Mercury ores and concentrates are initially processed by crushing, and
sometimes screening. Ore beneficiation techniques are not used extensively,
although flotation has been used at some facilities processing low-grade ore.
The crushed ore is then heated in either retorts, at small operations, or
furnaces, at large operations, to the temperatures at which mercuric sulphide
sublimates. The resulting mercury vapour is condensed in a cooling system and
collected as mercury metal. Soot from the condensers and settling tanks
should be removed, treated with lime and returned to the retort or furnace.
38. For efficient recovery of mercury the following techniques can be used:
Measures to reduce dust generation during mining and stockpiling,
including minimizing the size of stockpiles;
Indirect heating of the furnace;
Keeping the ore as dry as possible;
Bringing the gas temperature entering the condenser to only 10 to
20.0 above the dew point;
Keeping the outlet temperature as low as possible; and
Passing reaction gases through a post-condensation scrubber and/or
a selenium filter.
Dust formation can be kept down by indirect heating, separate processing of
fine grain classes of ore, and control of ore water content. Dust should be
removed from the hot reaction gas before it enters the mercury condensation
unit with cyclones and/or electrostatic precipitators.
39. For gold production by amalgamation, similar strategies as for mercury
can be applied. Gold is also produced using techniques other than
amalgamation, and these are considered to be the preferred option for new
40. Non-ferrous metals are mainly produced from sulphitic ores. For.
technical and product quality reasons, the off-gas must go through a thorough
dedusting (< 3 mg/m3) and could also require additional mercury removal before
being fed to an SO3 contact plant, thereby also minimizing heavy metal
41. Fabric filters should be used when appropriate. A dust content of less
than 10 mg/m3 can be obtained. The dust of all pyrometallurgical production
should be recycled in-plant or off-site, while protecting occupational health.
42. For primary lead production, first experiences indicate that there are
interesting new direct smelting reduction technologies without sintering of
the concentrates. These processes are examples of a new generation of direct
autogenous lead smelting technologies which pollute less and consume less
43. Secondary lead is mainly produced from used car and truck batteries,
which are dismantled before being charged to the smelting furnace. This BAT
should include one melting operation in a short rotary furnace or shaft
furnace. Oxy-fuel burners can reduce waste gas volume and flue dust
production by 60%. Cleaning the flue-gas with fabric filters makes it
possible to achieve dust concentration levels of 5 mg/m3.
44. Primary zinc production is carried out by means of roast-leach
electrowin technology. Pressure leaching may be an alternative to roasting
and may be considered as a BAT for new plants depending on the concentrate
characteristics. Emissions from pyrometallurgical zinc production in Imperial
Smelting (IS) furnaces can be minimized by using a double bell furnace top and
cleaning with high-efficiency scrubbers, efficient evacuation and cleaning of
gases from slag and lead casting, and thorough cleaning (< 10 mg/m3) of the
CO-rich furnace off-gases.
45. To recover zinc from oxidized residues these are processed in an IS
furnace. Very low-grade residues and flue dust (e.g. from the steel industry)
are first treated in rotary furnaces (Waelz-furnaces) in which a high-content
zinc oxide is manufactured. Metallic materials are recycled through melting
in either induction furnaces or furnaces with direct or indirect heating by
natural gas or liquid fuels or in vertical New Jersey retorts, in which a
large variety of oxidic and metallic secondary material can be recycled. Zinc
can also be recovered from lead furnace slags by a slag fuming process.
Table 7 (a) : Emission sources, control measures, dust reduction efficiencies
and costs for the primary non-ferrous metal industry
Emission source Control measure (a) Dust reduction Abatement
efficiency % costs (total
Fugitive emissions Suction hoods, enclosure, etc.
off-gas cleaning by FF 99 ••
Roasting/sintering Updraught sintering: ESP + .. 7 - 10/Mg
scrubbers (prior to double H2SO4
contact sulphuric acid plant) +
FF for tail gases
Conventional Shaft furnace: closed top/ .. .•
smelting (blast efficient evacuation of tap
furnace reduction) holes + FF, covered launders,
double bell furnace top
Imperial smelting High-efficiency scrubbing > 95 ..
Venturi scrubbers •• . .
Double bell furnace top .. 4/Mg metal
Pressure leaching Application depends on leaching > 99 site-specific
characteristics of concentrates
Direct smelting Flash smelting, e.g. Kivcet, .. ..
reduction Outokumpu and Mitsubishi
Bath smelting, e.g. top blown Ausmelt: Pb QSL: operating
rotary converter, Ausmelt, 77, Cd 97; costs
Isasmelt, QSL and Noranda QSL: 60/Mg Pb
processes Pb 92, Cd 93
. Table 7 (b): Emission sources, control measures, dust reduction efficiencies
and costs for the secondary non-ferrous metal industry
Emission source Control measure (s) Dust reduction Abatement
efficiency (%) costs (total
Lead production Short rotary furnace: suction 99.9 45/Mg Pb
hoods for tap holes + FF; tube
condenser, oxy-fuel burner
Zinc production Imperial smelting > 95 14/Mg Zn
46. In general, processes should be combined with an effective dust
collecting device for both primary gases and fugitive emissions. The most
relevant emission reduction measures are outlined in tables 7 (a) and (b).
Dust concentrations below 5 mg/m3 have been achieved in some cases using
Cement industry (annex II, category 7)
47. Cement kilns may use secondary fuels such as waste oil or waste tyres.
Where waste is used, emission requirements for waste incineration processes
may apply, and where hazardous waste is used, depending on the amount used in
the plant, emission requirements for hazardous waste incineration processes
may apply. However, this section refers to fossil fuel fired kilns.
48. Particulates are emitted at all stages of the cement production process,
consisting of material handling, raw material preparation (crushers, dryers),
clinker production and cement preparation. Heavy metals are brought into the
cement kiln with the raw materials, fossil and waste fuels.
49. For clinker production the following kiln types are available: long wet
rotary kiln, long dry rotary kiln, rotary kiln with cyclone preheater, rotary
kiln with, grate preheater, shaft furnace. In terms of energy demand and
emission control opportunities, rotary kilns with cyclone preheaters are
50. For heat recovery purposes, rotary kiln off-gases are conducted through
the preheating system and the mill dryers (where installed) before being
dedusted. The collected dust is returned to the feed material.
51. Less than 0.5% of lead and cadmium entering the kiln is released in
exhaust gases. The high alkali content and the scrubbing action in the kiln
favour metal retention in the clinker or kiln dust.
52. The emissions of heavy metals into the air can be reduced by, for
instance, taking off a bleed stream and stockpiling the collected dust instead
of returning it to the raw feed. However, in each case these considerations
should be weighed against the consequences of releasing the heavy metals into
the waste stockpile. Another possibility is the hot-meal bypass, where
calcined hot-meal is in part discharged right in front of the kiln entrance
and fed to the cement preparation plant. Alternatively, the dust can be added
to the clinker. Another important measure is a very well controlled steady
operation of the kiln in order to avoid emergency shut-offs of the
electrostatic precipitators. These may be caused by excessive CO
concentrations. It is important to avoid high peaks of heavy metal emissions
in the event of such an emergency shut-off.
53. The most relevant emission reduction measures are outlined in table 8.
To reduce direct dust emissions from crushers, mills, and dryers, fabric
filters are mainly used, whereas kiln and clinker cooler waste gases are
controlled by electrostatic precipitators. With ESP, dust can be reduced to
concentrations below 50 mg/m3. When FF are used, the clean gas dust content
can be reduced to 10 mg/m3.
Table 8: Emission sources, control measures, reduction efficiencies and
costs for the cement industry
Emission source Control measure (s) Reduction efficiency % Abatement costs
FF Cd, Pb: > 95 . .
Direct emissions ESP Cd, Pb: > 95
from rotary kilns, . .
clinker coolers ,
Direct emissions Carbon adsorption Hg: > 95
from rotary kilns
Glass industry (annex II, category 8)
54. In the glass industry, lead emissions are particularly relevant given
the various types of glass in which lead is introduced as raw material (e.g.
crystal glass, cathode ray tubes). In the case of soda-lime container glass,
lead emissions depend on the quality of the recycled glass used in the
process. The lead content in dusts from crystal glass melting is usually
55. Dust emissions stem mainly from batch mixing, furnaces, diffuse leakages
from furnace openings, and finishing and blasting of glass products. They
depend notably on the type of fuel used, the furnace type and the type of
glass produced. Oxy-fuel burners can reduce waste gas volume and flue dust
production by 60%. The lead emissions from electrical heating are
considerably lower than from oil/gas-firing.
56. The batch is melted in continuous tanks, day tanks or crucibles. During
the melting cycle using discontinuous furnaces, the dust emission varies
greatly. The dust emissions from crystal glass tanks (<5 kg/Mg melted glass)
are higher than from other tanks (<1 kg/Mg melted soda and potash glass).
57. Some measures to reduce direct metal-containing dust emissions are:
pelleting the glass batch, changing the heating system from oil/gas-firing to
electrical heating, charging a larger share of glass returns in the batch, and
applying a better selection of raw materials (size distribution) and recycled
glass (avoiding lead-containing fractions). Exhaust gases can be cleaned in
fabric filters, reducing the emissions below 10 mg/m3. With electrostatic
precipitators 30 mg/m3 is achieved. The corresponding emission reduction
efficiencies are given in table 9.
58. The development of crystal glass without lead compounds is in progress.
Table 9: Emission sources, control measures, dust reduction efficiencies
and costs for the glass industry
Emission source Control measure (s) Dust reduction Abatement costs
efficiency (%) (total costs)
FF > 98 ..
ESP > 90 . .
Chlor-alkali industry (annex II, category 9)
59. In the chlor-alkali industry, Cl2, alkali hydroxides and hydrogen are
produced through electrolysis of a salt solution. Commonly used in existing
plants are the mercury process and the diaphragm process, both of which need
the introduction of good practices to avoid environmental problems. The
membrane process results in no direct mercury emissions. Moreover, it shows a
lower electrolytic energy and higher heat demand for alkali hydroxide
concentration (the global energy balance resulting in a slight advantage for
membrane cell technology in the range of 10 to 15%) and a more compact cell
operation. It is, therefore, considered as the preferred option for new
plants. Decision 90/3 of 14 June 1990 of the Commission for the Prevention of
Marine Pollution from Land-based Sources (PARCOM) recommends that existing
mercury cell chlor-alkali plants should be phased out as soon as practicable
with the objective of phasing them out completely by 2010.
60. The specific investment for replacing mercury cells by the membrane
process is reported to be in the region of US$ 700-1000/mg Cl2 capacity.
Although additional costs may result from, inter alia. higher utility costs
and brine purification cost, the operating cost will in most cases decrease.
This is due to savings mainly from lower energy consumption, and lower waste-
water treatment and waste-disposal costs.
61. The sources of mercury emissions into the environment in the mercury
process are: cell room ventilation; process exhausts; products, particularly
hydrogen; and waste water. With regard to emissions into air, Hg diffusely
emitted from the cells to the cell room are particularly relevant. Preventive
measures and control are of great importance and should be prioritized
according to the relative importance of each source at a particular
installation. In any case specific control measures are required when mercury
is recovered from sludges resulting from the process.
62. The following measures can be taken to reduce emissions from existing
mercury process plants :
• Process control and technical measures to optimize cell operation,
maintenance and more efficient working methods;
• Coverings, sealings and controlled bleeding-off by suction;
- Cleaning of cell rooms and measures that make it easier to keep
them clean; and
Cleaning of limited gas streams (certain contaminated air streams
and hydrogen gas).
63. These measures can cut mercury emissions to values well below 2.0 g/Mg
of Cl2 production capacity, expressed as an annual average. There are
examples of plants that achieve emissions well below 1.0 g/Mg of Cl2
production capacity. As a result of PARCOM decision 90/3, existing
mercury-based chlor-alkali plants were required to meet the level of 2 g of
Hg/Mg of C12 by 31 December 1996 for emissions covered by the Convention for
the Prevention of Marine Pollution from Land-based Sources. Since emissions
depend to a large extent on good operating practices, the average should
depend on and include maintenance periods of one year or less.
Municipal, medical and hazardous waste incineration (annex II, categories 10
64. Emissions of cadmium, lead and mercury result from the incineration of
municipal, medical and hazardous waste. Mercury, a substantial part of
cadmium and minor parts of lead are volatilized in the process. Particular
actions should be taken both before and after incineration to reduce these
65. The best available technology for dedusting is considered to be fabric
filters in combination with dry or wet methods for controlling volatiles.
Electrostatic precipitators in combination with wet systems can also be
designed to reach low dust emissions, but they offer fewer opportunities than
fabric filters especially with pre-coating for adsorption of volatile
66. When BAT is used for cleaning the flue gases, the concentration of dust
will be reduced to a range of 10 to 20 mg/m3; in practice lower concentrations
are reached, and in sane cases concentrations of less than 1 mg/m3 have been
reported. The concentration of mercury can be reduced to a range of 0.05 to
0.10 mg/m3 (normalized to 11% 02) .
67. The most relevant secondary emission reduction measures are outlined in
table 10. It is difficult to provide generally valid data because the
relative costs in US$/tonne depend on a particularly wide range of
site-specific variables, such as waste composition.
68. Heavy metals are found in all fractions of the municipal waste stream
(e.g. products, paper, organic materials). Therefore, by reducing the
quantity of municipal waste that is incinerated, heavy metal emissions can be
reduced. This can be accomplished through various waste management
strategies, including recycling programmes and the composting of organic
materials. In addition, some UN/ECE countries allow municipal waste to be
landfilled. In a properly managed landfill, emissions of cadmium and lead are
eliminated and mercury emissions may be lower than with incineration.
Research on emissions of mercury from landfills is taking place in several
Table 10: Emission sources, control measures, reduction efficiencies and
costs for municipal, medical and hazardous waste incineration
Emission source Control measure (s) Reduction efficiency Abatement costs
(%) (total costs US$)
Stack gases High-efficiency Pb, Cd: > 98; • •
scrubbers Hg: ca. 50
ESP (3 fields) Pb, Cd: 80 - 90 10-20/Mg waste
Wet ESP (1 field) Pb, Cd: 95 - 99 ..
Fabric filters Pb, Cd: 95 - 99 15-30/Mg waste
Carbon injection + FF Hg: > 85 operating costs:
ca. 2-3/Mg waste
Carbon bed filtration Hg: > 99 operating costs:
ca. 50/Mg waste
TIMESCALES FOR THE APPLICATION OF LIMIT VALUES AND
BEST AVAILABLE TECHNIQUES TO NEN AND EXISTING
The timescales for the application of limit values and best available
(a) For new stationary sources: two years after the date of entry
into force of the present Protocol;
(b) For existing stationary sources: eight years after the date of
entry into force of the present Protocol. If necessary, this period may be
extended for specific existing stationary sources in accordance with the
amortization period provided for by national legislation. -27-
LIMIT VALUES FOR CONTROLLING EMISSIONS FROM MAJOR.
1. Two types of limit value are important for heavy metal emission control:
Values for specific heavy metals or groups of heavy metals; and
Values for emissions of particulate matter in general.
2. In principle, limit values for particulate matter cannot replace
specific limit values for cadmium, lead and mercury, because the quantity of
metals associated with particulate emissions differs from one process to
another. However, compliance with these limits contributes significantly to
reducing heavy metal emissions in general. Moreover, monitoring particulate
emissions is generally less expensive than monitoring individual species and
continuous monitoring of individual heavy metals is in general not feasible.
Therefore, particulate limit values are of great practical importance and are
also laid down in this annex in most cases to complement or replace specific
limit values for cadmium or lead or mercury.
3. Limit values, expressed as mg/m3, refer to standard conditions (volume
at 273.15 101.3 kPa, dry gas) and are calculated as an average value of
one-hour measurements, covering several hours of operation, as a rule 24
hours. Periods of start-up and shutdown should be excluded. The averaging
time may be extended when required to achieve sufficiently precise monitoring
results. With regard to the oxygen content of the waste gas, the values given
for selected major stationary sources shall apply. Any dilution for the
purpose of lowering concentrations of pollutants in waste gases is forbidden.
Limit values for heavy metals include the solid, gaseous and vapour form of
the metal and its compounds, expressed as the metal. Whenever limit values
for total emissions are given, expressed as g/unit of production or capacity
respectively, they refer to the sum of stack and fugitive emissions,
calculated as an annual value.
4. In cases in which an exceeding of given limit values cannot be excluded,
either emissions or a performance parameter that indicates whether a control
device is being properly operated and maintained shall be monitored.
Monitoring of either emissions or performance indicators should take place
continuously if the emitted mass flow of particulates is above 10 kg/h. If
emissions are monitored, the concentrations of air pollutants in gas-carrying
ducts have to be measured in a representative fashion. If particulate matter
is monitored discontinuously, the concentrations should be measured at regular
intervals, taking at least three independent readings per check. Sampling and
analysis of all pollutants as well as reference measurement methods to
calibrate automated measurement systems shall be carried out according to the
standards laid down by the Comitê européen de normalisation (CEN) or the
International Organization for Standardization (ISO). While awaiting the
development of the CEN or ISO standards, national standards shall apply.
National standards can also be used if they provide equivalent results to CEN
or ISO standards.
5. In the case of continuous monitoring, compliance with the limit values
is achieved if none of the calculated average 24-hour emission concentrations
exceeds the limit value or if the 24-hour average of the monitored parameter
does not exceed the correlated value of that parameter that was established
during a performance test when the control device was being properly operated
and maintained. In the case of discontinuous emission monitoring, compliance
is achieved if the average reading per check does not exceed the value of the
limit. Compliance with each of the limit values expressed as total emissions
per unit of production or total annual emissions is achieved if the monitored
value is not exceeded, as described above.
II. SPECIFIC LIMIT VALUES FOR SELECTED MAJOR STATIONARY SOURCES
Combustion of fossil fuels (annex II, category 1):
6. Limit values refer to 6% 02 in flue gas for solid fuels and to 3% O2 for
7. Limit value for particulate emissions for solid and liquid fuels:
Sinter plants (annex II, category 2):
8. Limit value for particulate emissions: 50 mg/m3.
Pellet plants (annex II, category 2):
9. Limit value for particulate emissions:
(a) Grinding, drying: 25 mg/m3; and
(b) Pelletizing: 25 mg/m3; or
10. Limit value for total particulate emissions: 40 g/Mg of pellets
Blast furnaces (annex category 3):
11. Limit value for particulate emissions: 50 mg/m3.
Electric arc furnaces (annex II, category 3).:
12. Limit value for particulate emissions: 20 mg/m3.
Production of copper and zinc. including Imperial Smelting furnaces (annex II,
categories 5 and 6):
13. Limit value for particulate emissions: 20 mg/m3.
Production of lead (annex II, categories 5 and 6):
14. Limit value for particulate emissions: 10 mg/m3.
Cement industry (annex II, category 7):
15. Limit value for particulate emissions: 50 mg/m3.
Glass industry (annex II, category 8):
16. Limit values refer to different O2 concentrations in flue gas depending
on furnace type: tank furnaces: 8%; pot furnaces and day tanks: 13%.
17. Limit value for lead emissions: 5 mg/m3.
Chlor-alkali industry (annex II, category 9):
18. Limit values refer to the total quantity of mercury released by a plant
into the air, regardless of the emission source and expressed as an annual
19. Limit values for existing chlor-alkali plants shall be evaluated by the
Parties meeting within the Executive Body no later than two years after the
date of entry into force of the present Protocol.
20. Limit value for new chlor-alkali plants: 0.01 g Hg/Mg Cl2 production
Municipal, medical and hazardous waste incineration (annex II, categories 10
21. Limit values refer to 11% O2 concentration in flue gas.
22. Limit value for particulate emissions:
10 mg/m3 for hazardous and medical waste incineration;
(b) 25 mg/m3 for municipal waste incineration.
23. Limit value for mercury emissions:
0.05 mg/m3 for hazardous waste incineration;
(b) 0.08 mg/m3 for municipal waste incineration;
(c) Limit values for mercury-containing emissions from medical waste
incineration shall be evaluated by the Parties meeting within the Executive
Body no later than two years after the date of entry into force of the present
PRODUCT CONTROL MEASURES
1. Except as otherwise provided in this annex, no later than six months
after the date of entry into force of the present Protocol, the lead content
of marketed petrol intended for on-road vehicles shall not exceed 0.013 g/1.
Parties marketing unleaded petrol with a lead content lower than 0.013 g/1
shall endeavour to maintain or lower that level.
2. Each Party shall endeavour to ensure that the change to fuels with a
lead content as specified in paragraph 1 above results in an overall reduction
in the harmful effects on human health and the environment.
3. Where a State determines that limiting the lead content of marketed
petrol in accordance with paragraph 1 above would result in severe
socio-economic or technical problems for it or would not lead to overall
environmental or health benefits because of, inter alia, its climate
situation, it may extend the time period given in that paragraph to a period
of up to 10 years, during which it may market leaded petrol with a lead
content not exceeding 0.15 g/1. In such a case, the State shall specify, in a
declaration to be deposited together with its instrument of ratification,
acceptance, approval or accession, that it intends to extend the time period
and present to the Executive Body in writing information on the reasons for
4. A Party is permitted to market small quantities, up to 0.5 per cent of
its total petrol sales, of leaded petrol with a lead content not exceeding
0.15 g/1 to be used by old on-road vehicles.
5. Each Party shall, no later than five years, or ten years for countries
with economies in transition that state their intention to adopt a ten-year
period in a declaration to be deposited with their instrument of ratification,
acceptance, approval or accession, after the date of entry into force of this
Protocol, achieve concentration levels which do not exceed:
(a) 0.05 per cent of mercury by weight in alkaline manganese batteries
for prolonged use in extreme conditions (e.g. temperature below 0°C or above
50°C, exposed to shocks); and
(b) 0.025 per cent of mercury by weight in all other alkaline
The above limits may be exceeded for a new application of a battery
technology, or use of a battery in a new product, if reasonable safeguards are
taken to ensure that the resulting battery or product without an easily
removable battery will be disposed of in an environmentally sound manner.
Alkaline manganese button cells and batteries composed of button cells shall
also be exempted from this obligation.
PRODUCT MANAGEMENT MEASURES
1. This annex aims to provide guidance to Parties on product management
2. The Parties may consider appropriate product management measures such as
those listed below, where warranted as a result of the potential risk of
adverse effects on human health or the environment from emissions of one or
more of the heavy metals listed in annex I, taking into account all relevant
risks and benefits of such measures, with a view to ensuring that any changes
to products result in an overall reduction of harmful effects on human health
and the environment:
(a) The substitution of products containing one or more intentionally
added heavy metals listed in annex I, if a suitable alternative exists;
(b) The minimization or substitution in products of one or more
intentionally added heavy metals listed in annex I;
(c) The provision of product information including labelling to ensure
that users are informed of the content of one or more intentionally added
heavy metals listed in annex I and of the need for safe use and waste
(d) The use of economic incentives or voluntary agreements to reduce
or eliminate the content in products of the heavy metals listed in annex I;
(e) The development and implementation of programmes for the
collection, recycling or disposal of products containing one of the heavy
metals in annex I in an environmentally sound manner.
3. Each product or product group listed below contains one or more of the
heavy metals listed in annex I and is the subject of regulatory or voluntary
action by at least one Party to the Convention based for a significant part on
the contribution of that product to emissions of one or more of the heavy
metals in annex I. However, sufficient information is not yet available to
confirm that they are a significant source for all Parties, thereby warranting
inclusion in annex VI. Each Party is encouraged to consider available
information and, where satisfied of the need to take precautionary measures,
to apply product management measures such as those listed in paragraph 2 above
to one or more of the products listed below:
(a) Mercury-containing electrical components, i.e. devices that
contain one or several contacts/sensors for the transfer of electrical current
such as relays, thermostats, level switches, pressure switches and other
switches (actions taken include a ban on most mercury-containing electrical
components; voluntary programmes to replace some mercury switches with
electronic or special switches; voluntary recycling programmes for switches;
and voluntary recycling programmes for thermostats);
(b) Mercury-containing measuring devices such as thermometers,
manometers, barometers, pressure gauges, pressure switches and pressure
transmitters (actions taken include a ban on mercury-containing thermometers
and ban on measuring instruments);
(c) Mercury-containing fluorescent lamps (actions taken include
reductions in mercury content per lamp through both voluntary and regulatory
programmes and voluntary recycling programmes);
(d) Mercury-containing dental amalgam (actions taken include voluntary
measures and a ban with exemptions on the use of dental amalgams and voluntary
programmes to promote capture of dental amalgam before release to water
treatment plants from dental surgeries);
(e) Mercury-containing pesticides including seed dressing (actions
taken include bans on all mercury pesticides including seed treatments and a
ban on mercury use as a disinfectant);
(f) Mercury-containing paint (actions taken include bans on all such
paints, bans on such paints for interior use and use on children's toys; and
bans on use in antifouling paints); and
(g) Mercury-containing batteries other than those covered in annex VI
(actions taken include reductions in mercury content through both voluntary
and regulatory programmes and environmental charges and voluntary recycling
I hereby certify that the
foregoing text is a true copy of
the Protocol to the 1979 Convention
on Long-Rangé Transboundary Air
Pollution on Heavy Metals, adopted
at Aarhus (Denmark) on 24 June 1998,
the original of which is deposited
with the Secretary-General of the
Je certifie que le texte qui
précede est une copie conforme du
Protocole a la Convention sur la
transfrontière a longue distance, de
1979, relatif aux métaux lourds,
adopté a Aarhus (Danmark) le
24 juin 1998, et dont l'original se
trouve déposé auprès du Secrétaire
général de l'Organisation des
For the Secretary-General, Pour le Secrétaire général,
The Assistant Secretary-General Le Sous-Secrétaire général
in charge of the Office chargé du Bureau des
of Legal Affairs affaires juridiques
United Nations, New York Organisation des Nations Unies
22 July 1998 New York, le 22 juillet 1998