Over 100,000 chemicals are currently in use world-wide and the number and
amount of chemicals used is still increasing. Many of these are hazardous
chemicals. Of particular concern are the persistent organic pollutants or
POPs.
Despite the extensive global production and use of POPs, our current understanding of the toxic effects of POPs on wildlife and humans is limited to only a handful of chemicals.
Only very recently governments started to acknowledge these problems and the need for their regional and indeed global elimination. The first steps are now being taken to eliminate POPs, but much more is needed to safeguard a toxic free future.
UNEP POPs
Convention
| A global and legally binding convention for the elimination of POPs was agreed in May 2001 under auspices of the United Nations Environment Programme (UNEP). This is a result of the 1992 UNEP Earth Summit in Rio de Janeiro. |
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The POPs convention
was signed in Stockholm in May 2001. It is also termed the Stockholm Convention.
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Banning the production and use of POPs globally is a significant and necessary step towards a toxic free future. The United Nations Environment Program (UNEP) lists twelve POPs, which are organochlorines, for priority action. The POPs treaty also includes a mechanism to add more POPs for elimination in the future. |
The 12
priority POPS are:
dioxins
and furans, (produced as unintentional by-products of combustion and processes
involving the manufacture, use and disposal of organochlorines);PCBs,
(industrial chemicals, the production of which has been banned but are still
in use and stockpiled and released to the environment in significant amounts
from old sources); HCB
(used in the manufacture of pesticides and produced as an unwanted by-product
of various industrial processes involving organochlorines); several
organochlorines used as pesticides, - DDT, chlordane, toxaphene, dieldrin,
aldrin, endrin, heptachlor and mirex.
Elimination of POPs
Environmental and health problems caused by POPs included on the UNEP list have been recognised for some years and, as a consequence, the PCBs and many of the pesticides have been banned or have restricted use in most countries, but not in all. For example, there is ongoing production and/or use of DDT in some countries (primarily for malaria vector control).
POPs do not respect national boundaries, such that their continued production and use in some countries continues to add to the global burden of these chemicals.
Moreover, dioxins and furans, as well as PCBs and HCB, are still produced as unwanted byproducts in numerous industrial and (waste) combustion processes.
It is therefore not surprising that there was strong opposition from a number of industrialised countries against the inclusion of these unintentionally produced substances for elimination under the UN POPs treaty.
The 12 UNEP POPs are only part of the problem we face. Many more persistent organic chemicals are still in widespread production and use in everyday products.
Although the greatest attention to date has focused, understandably, on persistent organochlorine chemicals, the general problem of the widespread contamination of the environment with persistent chemicals extends across other chemical groups.
| OSPAR
Convention A number of regional inter-governmental organisations, such as those responsible for the protection of regional sea areas (Mediterranean ((Barcelona Convention)), North Sea, Baltic Sea, North East Atlantic), |
| have recognised that, in order to ensure protection of the environment, action must be taken to reduce and ultimately prevent emissions of all hazardous substances, particularly those which are persistent and bioaccumulative. |  |
The Convention
for the Protection of the Marine Environment of the North East Atlantic
(the OSPAR Convention) covers 15 States of the North East Atlantic Region
and the European Union. In 1998, Ministers of the OSPAR countries agreed
to a target for the cessation of discharges, emissions and losses of all
hazardous substances to the marine environment in ONE GENERATION (i.e. by
the year 2020).
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The OSPAR Convention is to date the most far reaching regional Convention for the elimination of hazardous substances. |
An initial list of 15 chemicals or chemical groups of particular concern has been selected (OSPAR 1998a). This "list of chemicals for priority action" includes a variety of POPs and other hazardous substances, e.g. heavy metals. Some of these POPs have already been phased out of mainstream production such as pentachlorophenol, but others are still produced and released to the environment on a daily basis. OSPAR member States are committed to draw up a programme of measures to eliminate the substances on the priority list by 2003. They are also committed to agree on a mechanism to prioritise other hazardous chemicals by 2000.
The current OSPAR list for priority action includes dioxins and furans, brominated flame retardants, HCH isomers - such as the organochlorine pesticide lindane, musk xylene (used as a synthetic fragrance), organotin compounds (for example, used as anti-fouling agents for ships), short chained chlorinated paraffins (for example, used in cutting oils and lubricants) and certain phthalates - DBP and DEHP, which are relatively less persistent but are none the less hazardous (main uses as plastic softeners, especially in PVC) and, as a result of their continued widespread use and release, are among the most ubiquitous man-made chemicals in the environment.
The OSPAR member
states are Belgium, Denmark, The European Commission, Finland, France, Germany,
Iceland, Ireland, Luxembourg, The Netherlands, Norway, Portugal, Spain,
Sweden, Switzerland and the UK.
| Chemical
Policy in the European Union In order to implement the OSPAR commitments, the EU Chemical Policy and EU Directives and Regulations need to be compatible with OSPAR. But so far the EU has not implemented any of the OSPAR commitments in its own environmental policy. |
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The manufacture, marketing and use of chemicals within the European Union is currently regulated under a complex system of Directives and Regulations which have, as their fundamental basis, the objective of maintaining the free circulation of chemical products for economic purposes.
Furthermore, this legislation is based on the assessment and management of the "risks" presented by chemicals. In simple terms, risk is determined as a product of the hazardous properties of a chemical and an estimation of the degree to which the environment, including humans, are exposed to that chemical.
In other words, even if a chemical is known to possess highly hazardous properties and pose a risk to the environment or human health, it is possible that the over-all assessment will conclude that the risks are acceptable as exposure will only occur at levels below those at which adverse effects might be predicted, or that a causal relationship between dose and effects has yet to be firmly established.
In such cases, despite the hazardous nature of the chemical, it is likely that no further regulation would be required. This represents a fundamental departure from the more precautionary, hazard-based approach required by OSPAR.
In addition to the fundamental limitations to risk-based regulation, the existing system of chemical regulation in Europe is widely seen to have failed to deliver timely and effective measures for other institutional reasons.
This is particularly
true with respect to the so-called "existing chemicals", i.e.
more than 100,000 chemicals which were listed as being marketed or used
in Europe prior to 1982.
Since the adoption
of Regulation 793/93 on the evaluation and control of the risks of existing
substances, only 38 of the 110 substances prioritised as particularly hazardous
have been, or are undergoing discussion. To date, no effective action has
been taken for any of these priority substances under this Regulation.
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The
European Commission is currently reviewing the way in which it evaluates
and controls chemicals. In order to implement the commitments of OSPAR,
to which the European Commission is signatory, and the precautionary
principle, incorporated as a guiding principle in the EU Treaty, the
process of chemical regulation within the EU must undergo a fundamental
revision: phase out programmes for chemicals with inherent hazardous
characteristics and their replacement with non-hazardous alternatives,
persuant to the precautionary principle. |
POPS listed by UNEP and OSPAR
Most research on POPs is limited to a few of these chemicals and information on the remaining ones has only begun to be generated more recently. Similarly, there are vast numbers of other hazardous chemicals for which there is little scientific data. It should also be stressed that the UNEP and OSPAR lists are not complete lists of POPs and hazardous chemicals. There are numerous others which are also environmental contaminants and are of great concern.
The creation of such a list is only the start of the process - it is clearly not a solution in itself. The diversity of uses of these chemicals, and their releases to the environment, serve to illustrate the scale of the problem to be addressed. We are all exposed to hazardous chemicals, including POPs, during daily life, both because of there pervasive distribution throughout the environment, including the food we eat, and because of their use in consumer products. We know that these chemicals can be harmful. We know something of the threats to human and wildlife health of long-term exposure to complex mixtures of these chemicals. What we already know is cause enough for grave concern and for immediate action to initiate the phase out the production and use of all hazardous chemicals.
POPs listed by UNEP
Dioxins and furans: Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are commonly known as dioxins and furans respectively. There are more than 200 individual congeners, although some are more toxic, and some more abundant, than others are are. 2,3,7,8-TCDD is probably the most toxic form and is now recognised as a human carcinogen. Dioxins are produced as unintentional by-products of many manufacturing and combustion processes, especially processes that use, produce or dispose of chlorine or chlorine derived chemicals. Important sources of dioxins to the environment include waste incineration and many organochlorine production processes, including PVC production.
Polychlorinated Biphenyls (PCBs): PCBs comprise of a group of 209 different congeners. Around half this number has been identified in the environment. The more highly chlorinated PCB congeners are the most persistent and account for the majority of those polluting the environment. PCBs were produced as industrial chemicals that were mainly used for insulation in electrical equipment. Production of PCBs has almost totally ceased worldwide, although there are reports of it continuing in Russia. At least one third of PCBs that have been produced are estimated to have entered the environment (Swedish EPA 1999). The other two thirds remain in old electrical equipment and in waste dumps from where they continue to leach into the environment. Although this is the major source of PCB pollution in the environment today, some PCBs are also produced as by-products of incineration and certain chemical processes involving chlorine.
Hexachlorobenzene (HCB): This chemical was previously used as a fungicide for seed grain. It is also produced unintentionally as a by-product during the manufacture of chlorinated solvents, other chlorinated compounds, such as vinyl chloride, and several pesticides. It is a by-product in waste streams of chlor-alkali plants and wood preserving plants, and in fly ash and flue gas effluents from municipal waste incineration. Its major source today remains the manufacture of pesticides (Foster 1995, ATSDR 1997).
Organochlorine Pesticides: There are eight pesticides in this category listed by UNEP. These are aldrin, dieldrin, endrin, DDT, chlordane, mirex, toxaphene and heptachlor. The majority of these are banned or restricted in many countries, although not all. For example, DDT is still widely used in developing countries particularly for mosquito control (e.g. Lopez-Carrillo et al. 1996).
POPs on the OSPAR Priority list of chemicals
Hexachlorocyclohexane isomers (HCH): Including g-HCH, or lindane, an organochlorine pesticide and a component of some shampoos for treatment of headlice. Its use as a pesticide in agriculture has declined in recent years, but it nevertheless continues to be used for this purpose in some countries of Europe (Swedish EPA 1999). Use of technical HCH, a mixture of HCH isomers including alpha-HCH, is yet more restricted. Nevertheless, as a result of some continued releases and its persistence in the environment, alpha-HCH remains widespread in the environment, including the Arctic.
Brominated
flame retardants: These chemicals are widely used as fire retardants in
electronic equipment e.g. electronic boards in computers, radios and television
sets, in plastics, textiles, building materials, carpets and in vehicles
and aircraft. The production and use of some these chemicals are increasing.
Brominated flame retardants include polybrominated diphenyl ethers (PBDEs),
and polybrominated biphenyls (PBBs), as well as the more recently developed
tetrabromobisphenol-A. It is becoming increasingly clear that PBDEs are
widely distributed in the global environment and can accumulate in the tissues
of humans and wildlife; similar evidence is growing for other brominated
flame retardants
| Organotin Compounds: Organotin compounds are used as active ingredients in anti-fouling agents, fungicides, insecticides and bactericides. One of the chemicals in this group, tributyltin (TBT), has been used as an anti-fouling agent in paints for boats and aquaculture nets since the 1960s, although its use is now restricted to large vessels and a global ban is under discussion. |  |
TBT is perhaps best known for its hormone disrupting effects in marine invertebrates, although it is also highly toxic to other organisms. It has been described as perhaps the most toxic chemical ever deliberately introduced into natural waters and has become widespread in the marine environment.
Short Chain Chlorinated Paraffins: These chemicals have for many years been used to produce a range of products, including use as fire retardants and plasticisers in PVC, rubber and other plastics, varnishes, sealants and adhesives, leather treatment chemicals and as extreme pressure additives in lubricants and metal cutting oils (Campbell and McConnell 1980). It should be noted that it is not just the short-chained chlorinated paraffins that are problematic but the whole group of chlorinated paraffins.
Musk Xylene: This chemical is a nitro-musk which, along with musk ketone, is widely used as a fragrance additive in place of natural musk extracts in cosmetics and detergents. Polycyclic musks are being used increasingly in Europe instead of nitro musks. However, all synthetic musks are persistent in the environment.
Certain Phthalates
- dibutylphthalate (DBP) and diethylhexylphthalate (DEHP): These chemicals
are just two of many other phthalates which are used in industry and which
have become ubiquitous environmental contaminants. While phthalates are
not as persistent as some of the other POPs, they are continuously released
to the environment from use in consumer products, particularly as plasticisers
in soft PVC (in toys, furniture, flooring, vehicles, clothing, etc.) which
accounts for approximately 90 percent of phthalate use. Phthalates are also
used, however, in some other plastics and in non-plastic applications e.g.
as additives in paints, pesticides, inks, perfumes, cosmetics and insectepellents.
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