Substances that are persistent, i.e. do not easily degrade, have a potential for widespread exposure through winds and streams and through trade in chemicals and products. When problems are identified exposure cannot be easily reduced by discontinuing production. Problems caused by persistent chemicals are therefore long lasting.
Many fat-soluble organic substances show extreme accumulation in organisms and concentrate more than several orders of magnitude. They may also biomagnify, i.e. concentrations increase for each step in the food chain, from algae to small crustaceans through fish to seals, eagles or man. Sooner or later they reach concentrations where adverse effects occur. When such chemicals are released to the environment they will redistribute themselves to end up in organisms at the top of the food chain, e.g. man. Discontinuation of their production and use will not alleviate the situation for a long time for those already exposed.
Experience tells us that new unexpected effects of chemicals will appear in the future. For substances in use that are persistent and liable to bioaccumulate that knowledge will come too late. To prevent injury to man and the environment in the future action must be taken when there is evidence of potential persistence and bioaccumulation. Substances with such properties should in principle not be used at all, unless they can be controlled to a similar degree as radioactive chemicals.
2. Managing POPs pesticides
A limited system for pesticide registration was introduced in Sweden in 1953. The producer had to obtain a registration from the Swedish Plant Protection Institute to market a product containing substances on an official poison list. The registration was usually based on very limited information on the active ingredient and the product. Products which did not contain toxic substances were left outside the system. With the rapid growth of pesticide use in the 50s this system became insufficient. A registration system covering all pesticides was introduced in 1963. The basic concept of the system was that all uses of pesticides are banned unless a specific product has been approved by the appropriate designated Government agency. Over the years the registration system has become more and more strict. In 1980 formal data requirements were established. Applications that did not fulfill the data requirements could then be rejected because of insufficient data. Registrations, however, had no time limit and could only be recalled following new information on effects.
In 1986 Sweden established a system of time limited pesticide approvals. Approvals are given for a maximum of five years. Following the substitution principle, an old pesticide with unwanted side effects may be cancelled when a new pesticide with more acceptable health and environmental effects has been approve. In the present system, there are also cut-off levels that are applied to identify unacceptable pesticides (KemI Report [4/92]).
Concerning the presently discussed nine pesticide POPS, Sweden has implemented a strong policy on persistent organic pollutants, especially the twelve now being discussed in connection with the UNEP Governing Council Decision 18/32. Endrin was banned in Sweden as early as 1966 and all uses of aldrin and dieldrin were banned in 1970. Home and garden use of DDT was also banned in 1970. The remaining use was in forestry against a beetle that attacked pine and spruce seedlings. This use was continued on dispensation for each individual case until 1975. The use of chlordane was banned in 1971 and hexachlorobenzene for pesticide use was voluntarily withdrawn from the Swedish market in 1980. The other pesticide POPs, i.e. toxaphene, mirex and heptachlor, have never been used in Sweden. Toxaphene, however, may still be found in considerable concentrations in e.g. fish in Sweden.
3. The basic precautionary approach towards chemicals management
In Sweden, the precautionary approach has been systematically applied since the early 70s. It is also codified in Article 5 of the Act on Chemical Products. In the Article it is stated:Anyone handling or importing a chemical product must takes such steps and otherwise observe such precautions as are needed to prevent or minimize harm to man or the environment. This includes avoiding chemical products for which less hazardous substitutes are available. (my italics).
The pesticide area shows the most evident, earliest, and most well established use of the precautionary principle in Sweden. Many pesticides that were cancelled or withdrawn in the 70s and early 80s had limited data sets that would not in any modern sense of the word be considered sufficient for risk assessment. Rather it was the inherent toxicity and the potential risk of substances such as aldrin, dieldrin and endrin that caused the Swedish authorities, first the Poison Board, and later the Products Control Board to cancel their registration. When DDT was cancelled for most uses in 1969 the reason was suspected effects in the environment, including eggshell thinning of birds of prey, but the direct link to DDT was weak and was questioned. Also, the health effects were not prominent, and well designed studies on chronic effects in animals were not available until much later. The decision was not unanimous. The opponents pointed to the great economic importance of DDT in forestry, and the great costs that would entail from a ban on its use in view of the fact that the forestry based sectors of industry, e.g. timber, furniture and pulp and paper industries, contributed more to Swedish export earnings than any other single sector of industry. Experience showed, however, that alternatives quickly worked their way into forestry, and if anything, the output today is higher per unit area than in the 60s.
Several pesticides were cancelled because less hazardous alternatives were available. The 'drins' is a good example. Another non-POP example is parathion and its derivatives, which were cancelled since an alternative, fenitrothion, was available. Similar arguments were used for the cancellation of the herbicides dinoseb and amitrol in 1972.
Pesticide management has recently become more of a responsibility of the users. In 1985 the Swedish Government proposed halving the use of agricultural pesticides. KemI was given the task to carry out this programme together with the Board of Agriculture, The National Food Administration and the Swedish Environment Protection Agency. The role of KemI in the programme was to make sure that old, hazardous pesticides were systematically substituted, whenever possible, by more modern, more well documented, and less hazardous pesticides. The process was very successful and reduced pesticide use in agriculture by 65% in ten years. A large part of this must be attributed to a changed attitude of the Swedish Farmers Association. This organisation has recently developed a policy of making Swedish agriculture the'greenest' within the European Union. Consequently, they have encouraged the farmers to use as few and as little pesticides as possible. As a result Swedish farmers retain or increase their domestic market shares for every incident of contaminated or diseased food from other countries in Europe or elsewhere.
4. Managing PCBs
In 1966 PCBs were identified for the first time in fat from animals in the Baltic by Danish born scientist Sören Jensen. Five years later, 1971, the first legal step to restrict PCB in Sweden was taken by the introduction of the Act on PCB. The first regulation have been followed by several others. The Ordinance on PCB was revised in 1989 and a final time limit for the use of existing PCB in transformers and capacitors was set to January 1st 1995. A general strategy for the Swedish phase-out of PCB has been to move in steps, first stopping dispersed uses, then any new uses in electrical installations, and then step by step getting rid of remaining quantities in existing installations at a pace determined by the domestically available destruction capacity.
Concentrated PCB oils as well as PCB-contaminated oils from cleaning transformers and capacitors are covered by the Ordinance on Hazardous Waste. There are no numerical standards in the regulation, but as a guidance value oils containing less than 500 ppm PCB have been allowed to be used for the normal life time of the equipment in which they are housed. The Swedish view on what is PCB-waste is very strict. In essence oils containing more than 2 ppm are regarded as hazardous waste. The EU directive at present sets the limit to 50 ppm.
Linked to the phase out of PCBs there has been continuos monitoring programmes particularly in the Baltic Sea. Since the early seventies there has been a decrease in PCB levels of about 80% in biota, as reflected in PCB content in guillemot eggs. For DDT the drop has been even larger, close to 90 %.
5. Dioxins and furans
Dioxins and furans appear as contaminants in some pesticides and wood preservatives. The major sources are however emissions from various industries including incineration processes. In Sweden the general management of dioxin releases has occurred through the Franchising Board, which has set limits for emissions, based on data from the Swedish EPA and other sources. Sweden has performed several surveys of dioxin sources, to dimensionalize the problem, and to prioritise measures. One of the major sources is the incineration of municipal solid waste. Another is the metal industry, including smelters of scrap metal.
Chlorine bleaching of paper pulp, which was a contributor to pollution by these and other persistent chlorinated compounds, has essentially stopped in Sweden today. Some chlorine dioxide is still being used, but this process produces much less dioxin contamination. Also other processes, e.g. smeltering of used metals have been cleaned up. The reduced use of leaded petrol and consequently also a reduction of the halogenated additives contained in leaded petrol, which produces dioxines, has led to decreasing levels of releases of dioxins and furans from traffic in Sweden. Other direct measures have been to ban pesticides containing dioxins as microcontaminants, e.g. pentachlorphenol and 2,4,5-T.
|Table. Releases of PCDD/Fs ( grams of TEQ) from known sources 1987, 1992, 1993|
|Source 1987 1992 1993*|
|Municipal Waste incineration 20-30 2 3.4-3.7|
|Hospital waste incinerators 10 0.5 <1|
|Incineration of hazardous waste 2-6 0 <1|
|Traffic 5-15 5-12 0.9-2.9|
|Pulp and paper industry
-to air 4-6 4-5 1
-to water 15-30 1-2 1.5-5
|Metal Industry 20-45 9 6.4-24|
|Cement and limestone industry 5-10 2 2.9-6|
|Coal fired power stations 1 1 <1|
* Figures for 1993 are preliminary estimates
6. Known or suspected effects of POPs on man and wildlife in Sweden
In the early 70s there were several species of birds of prey, e.g. the white tailed eagle, the great horned owl and the peregrin falcon all rapidly approaching extinction in Sweden. Eggshell thinning due to DDT was one of the reasons, but there might have been other subtle effects on behaviour influencing mating behaviour which went undiscovered. Also the grey seal of the Baltic was threatened as well as the mink and the otter. For the grey seal the situation was particularly serious since the fraction of young females producing offspring was drastically reduced. Sceletal deformities, blocked uteri and hypertrophic adrenals were found during autopsy of animals found dead. This was linked to high levels of PCBs in body fats.
There are at present no indications of adverse health effects in Sweden that can be related to levels of POPs in the general population. However, recent case control studies on exposed populations, e.g. fishermen and their families with a high intake of contaminated fish, have shown decreased birth weights of babies from mothers with high exposure to POPs, expressed as TEQs. There has also been evidence of increased incidences of various soft tumours in case control studies on populations exposed to phenoxy herbicides, some of which might have been contaminated by dioxins.
Levels of DDT, PCBs and dioxins in human breast milk have decreased substantially since the 70s. The intake of dioxin and dioxin like compounds in breastfed babies, however, still exceeds the recommended daily intake of 10 pg TEQs/kg/day (WHO).
7. Some results of managing POPs in Sweden
For the threatened species of birds of prey drastic measures were taken to promote their survival. Eggs from the great horned owl and the peregrin falcon were hatched in captivity and for the great horned owl the young birds were also reared in captivity on uncontaminated food until adult age and then released. Several hundred healthy birds were added to the fauna in this way. The white tailed eagles were fed with non-contaminated fish or meat at their normal winter gathering places throughout the winter season for several years.
Today these birds of prey are no longer threatened with extinction, although the populations are still smaller than in the period before the massive use of persistent organochlorines. The grey seal population is also increasing and the fraction of fertile females is approaching normal levels, i.e. 80-90%. The mink and the otter are also recovering, the otter more slowly because of its habit of delivering only one or two pups per year.
Concomitantly with the threats of extinction to species at the top of the food chain it was clearly shown that levels of persistent organochlorines had increased substantially in biota in the 50s and 60s. Similarly, the levels in biota fell sharply (80-90%) in the 70s and 80s following restrictions on uses and bans. Lately the decrease is levelling off, and there has been indications of an upward trend. This has been interpreted as the result of long range transport from distant sources at lower latitudes. Levels of DDT and PCB in breast milk have fallen sharply since the 70s.
The Swedish National Food Administration has issued recommendations on consumption of fatty fish, i.e. salmon, trout and herring, for girls and women of child-bearing age. They should not eat such fish from the Baltic more than once a month. Other consumers should not eat such fish more than once a week.
8. Recent proposals for new chemicals policies in Sweden
A Chemicals Policy Committee established by the Swedish Government recently reported on a review of Swedish chemicals policies for the last ten years and proposed a new chemicals policy for the future. Some issues related to the POPs will be mentioned here.
The Chemicals Policy Committee proposed the following targets for the future chemicals policy:
By the year 2007 all products, including chemicals, on the market should be free from substances that are persistent and liable to bioaccumulate and substances that give rise to serious or irreversible effects on health or the environment.
By the year 2012 the production processes should have developed to the extent that they are free from the deliberate use of persistent and bioaccumulating substances and the releases are free from substances that cause serious or irreversible effects on health or the environment.
The targets are intended to create driving forces for change
The targets of the Chemicals Policy Committee are intended as a proposal for how Sweden and the European Union shall reach the overriding targets of the Esbjerg Declaration. They are forward-looking and intended to generate driving forces for changes in the choice of chemicals and products and in requirements for products. Purchasers should use them as requirements when they purchase products from their suppliers. Consumers should use them to formulate environmentally sound requirements and to choose between products. The targets should guide the regulatory agencies in their national and international work. They also have a long time frame to allow for changes in product development and production processes to occur.
Proposed criteria for persistence and bioaccumulation
The Committee realised that there are no readily available test methods suitable for determining persistence. Based on available methods the Chemicals Policy Committee considered as persistent, substances that are not degraded (more than 20%) in internationally standardised and accepted tests for Ready Biodegradability, or in internationally standardised and accepted tests for Inherent Biodegradability.
The term liable to bioaccumulate has been used scientifically to describe substances with a bioconcentration factor (BCF) of 100 or more, or a partition coefficient between n-octanol and water (Kow) of 1,000 or more (logKow>3). The Chemicals Policy Committee considered that, as a first step, substances with a BCF>10,000 or a Kow>100,000 (logKow>5) should be phased out, but that this level would have to be adjusted in the light of future knowledge.
Proposed measures and strategies at the international level
At the international level Sweden will be working primarily through the Intergovernmental Forum on Chemical Safety. Sweden can also pursue issues by hosting meetings between government and industry at high level, e.g. the Round Table Meeting between Ministers of Environment and Chief Executive Officers held in Stockholm in January 1996. Sweden shall actively advocate the targets of the Chemicals Policy Committee internationally, in order to achieve a broader consensus on them.
Sweden will work for the targets of the Esbjerg Declaration of the 4th International Conference on the Protection of the North Sea to guide the global chemicals work. Sweden will also work in different international organisations for the concept that the global use of chemicals should be compatible with sustainable development. Sweden will put priority on international work which aims at restrictions on releases and use of persistent, bioaccumulating substances. The Esbjerg Declaration should in the long-term include all substances that are persistent and liable to bioaccumulate.
Sweden will actively pursue the work on a global convention for persistent organic pollutants, and intends to support the work with national expertise. Sweden is also interested in developing criteria that will identify further substances.
An important part of any international chemicals policy is the linkage to development assistance. The Committee has proposed that the Swedish International Development Assistance Agency be commissioned to present a report, together with the National Chemicals Inspectorate and the Swedish Environmental Protection Agency, on how bilateral co-operation on environmental issues may be integrated with a global plan of action to implement the Esbjerg Declaration. The report should take into consideration how bilateral co-operation and capacity building may support the implementation of a future global convention on persistent organic pollutants.