Annex 2
GEF PDF-B Regionally Based Assessment of Persistent Toxic Substances
1st Steering Group Meeting
Geneva, 11-13 November 1998
Topics to Be Discussed and sub-categories of chemicals to be addressed at the
Technical Expert Workshops
1. Workshop on Persistent Manufactured Chemicals
The substances in this group for Workshop 1 (WS 1) include manufactured chemicals as well as
unwanted byproducts from chemical industrial processes and combustion processes. Some of
the chemicals were produced in large amounts in the past and are still present in uses; e.g. PCB
in transformers and capacitors. For such substances, disposal of obsolete stocks and carcasses is
of primary importance. For some chemicals in use e.g. brominated flame retardants (brominated
diphenyl ethers), recycling may generate high concentrations of polybrominated dioxins and
furans. Depending on the industrialization of a country or region, there will be different
priorities, e.g. in the highly industrialized countries advanced technology makes waste
incineration no longer a major source of PCDD/PCDF, while illegal burning of wastes in less
developed regions may generate high amounts of PCDD/PCDF. Disposal of waste, both
municipal solid as well as hazardous wastes, are major sources of unwanted byproducts (besides
PCDD/PCDF, hexachlorobenzene (HCB) and polycyclic aromatic hydrocarbons should be
mentioned).
The categories to be discussed are as follows:
Manufactured chemicals: Polychlorinated biphenyls (PCB). Brominated flame retardants such
as polybrominated biphenyls (PBB), polybrominated diphenyl ethers (PBDE),
tetrabromopbisphenol A (TBBA), PCB replacements such as polyhalogenated
monomethyldiphenyl methanes (Ugilecs), polychlorinated naphthalenes (PCN, halowaxes),
polychlorinated paraffins, polychlorinated terphenyls (PCT), nitromoschus compounds as well
as polychlorinated benzenes, pentachlorophenol ( as wood preservatives) and phthalates.
Sucrose polyesters may be an emerging issue.
Combustion byproducts and impurities: Polychlorinated dibenzo-p-dioxins (PCDD),
polychlorinated dibenzofurans(PCDF), hexachlorobenzene (HCB), polycyclic aromatic
hydrocarbons (PAH), polychlorinated styrenes (phenyl ethylenes), polybrominated dibenzo-pdioxins and polychlorinated dibenzofurans (PBDD/PBDF), structurally related compounds (to
PCDD/PCDF) such as chlorinated thiophenes, azarenes, etc.
Issues to be addressed include:
- Rationale for assigning priorities to persistent toxic chemicals in the full project based on
criteria e.g. persistence, lipophilicity, toxicity, structure-activity considerations, doseresponse relationships etc.
- Rationale for exclusion or inclusion of chemicals
- Individual evaluations, including the uncertainty in the evaluation, of the chemicals with a
view to determining the approach in the full assessment as described in project brief 3.2.
- For each chemical, aspects to be considered in the full project e.g.
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Sources (intentional, unintentional)
Use pattern
Transport mechanisms, distribution between media
Monitoring, screening
Toxicity and health impacts: Environmental, ecotoxicological, and human
Sensitive endpoints, e.g. species differentiation of developmental stages: Risk-specific
(compound-wise and regionally)
Analytical requirements to accurately determine concentrations of these chemicals
Elimination, reduction/minimization, continuation
Legal and regulatory aspects at national, regional and international level
Socioeconomic aspects
2. Workshop on Persistent Organic Pesticides
The group includes organic substances used in agriculture, human health and related sectors, e.g.
silviculture, aquaculture and horticulture, as well as biocides used as slimicides, anti-fouling
agents, desinfectants, etc, as well as any persistent metabolites or degradation products with
toxic properties.
The substances in this group include those presently under negotiations for a global instrument
on POPs, e.g. aldrin, dieldrin, DDT, endrin, chlordane, mirex, toxaphene, heptachlor and
hexachlorobenzene, as well as chemicals on the FAO list of persistent pesticides (to be
checked), chlordecone, HCH, endosulfan, atrazin and related chloro and aminotriazines,
glyphosate, and possibly others.
Issues to be addressed include:
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Rationale for assigning priorities to persistent toxic chemicals in the full project based on
criteria e.g. persistence, lipophilicity, toxicity, structure-activity considerations, doseresponse relationships etc.
Rationale for exclusion or inclusion of substances in the list
Individual evaluations, including the uncertainty in the evaluation, of the chemicals with a
view to determining the approach in the full assessment as described in project brief 3.2.
For each chemical, aspects to be considered in the full project e.g.
Sources (intentional, unintentional)
Use pattern
Transport mechanisms, distribution between media
Monitoring, screening
Toxicity and health impacts: Environmental, ecotoxicological, and human
Sensitive endpoints, e.g. species differentiation of developmental stages: Risk-specific
(compound-wise and regionally)
Analytical requirements to accurately determine concentrations of these chemicals
Elimination, reduction/minimization, continuation
Legal and regulatory aspects at national, regional and international level
Socioeconomic aspects
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Primary targets for immediate exposure to pesticides
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Transport pathways, e.g. erosion from soil surfaces as well as wash out effects after
irrigation or heavy rainfalls of relevance compared to long-range transport
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Factors influencing the transboundary movement of the chemicals applied in agriculture
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Factors of importance for pesticides applied for preservation of wood, textiles, and leather as
well as for conservation of other goods?
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Disposal of treated products after use, e.g. the problem of unregulated disposal or chemicals
as precursors for formation of unwanted byproducts e.g. when incinerated.
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Assessment of new pesticides without the properties of bioaccumulation and lipophilicity but
with e.g. a much higher acute toxicity towards aquatic organisms.
3. Workshop on Persistent Organometallic Compounds
This group includes organometallic substances that are used in aquatic applications, such as
aquaculture, shipping /antifouling etc.
The group primarily includes anthropogenic substances e.g. alkyl tin compounds, recognizing
that there might be compounds with other elements warranting consideration. There are several
generic issues common to this group of chemicals and that of pesticides. It might be useful to
hold the workshop back-to-back with the pesticide workshop.
Issues to be addressed include:
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Rationale for assigning priorities to persistent toxic chemicals in the full project based on
criteria e.g. persistence, lipophilicity, toxicity, structure-activity considerations, doseresponse relationships etc.
Rationale for exclusion or inclusion of substances in the list
Individual evaluations, including the uncertainty in the evaluation, of the chemicals with a
view to determining the approach in the full assessment as described in project brief 3.2.
For each chemical, aspects to be considered in the full project e.g.
Sources (intentional, unintentional)
Use pattern
Transport mechanisms, distribution between media
Monitoring, screening
Toxicity and health impacts: Environmental, ecotoxicological, and human
Sensitive endpoints, e.g. species differentiation of developmental stages: Risk-specific
(compound-wise and regionally)
Analytical requirements to accurately determine concentrations of these chemicals
Elimination, reduction/minimization, continuation
Legal and regulatory aspects at national, regional and international level
Socioeconomic aspects
Speciation of the metal affecting the evaluation of threats posed by these compounds and
the chemical analysis.