Persistent Organic Pollutants Stiff and lean after six months curled in a den, a female polar bear squeezes herself out of her winter home. Two small cubs emerge tentatively at her heel for their first view of the world beyond a snow cave. Entirely dependent on their mother, the cubs follow obediently. Having used up most of her fat stores, the female scans the sea ice below and ponders a meal of seal blubber. But her cubs are not yet ready to travel, and her milk will have to sustain them for some time to come. The milk is rich and nourishing but today it also harbors a threat. The seals the mother has feasted on in the past, and will need again soon, are tainted by chemicals from lands far beyond her sea-ice domain. The chemicals that bind to the fat of the seals have accumulated in her own fat stores. Unwittingly, the mother passes the toxins to her young in her fat-rich milk, with effects that are still unclear. This chapter examines organic chemicals that can affect the health of animals and people, especially those substances that accumulate in Arctic food webs and that resist degradation. These are often called persistent organic pollutants, or POPs. A review of known toxic effects and environmental levels of POPs forms the basis for evaluating whether Arctic wildlife are affected by current levels of contamination. A summary of sources and pathways indicates where the contaminants come from. Many measurements of organic contaminants have been made because of concern about high intake by people, and the human health aspects of these substances are discussed in the chapter Pollution and Human Health. Persistent organic pollutants: a background Persistent Organic PollutantsPersistent Organic Pollutants (POPs) are chemical substances that persist in the environment, bioaccumulate through the food web, and pose a risk of causing adverse effects to human health and the environment. With the evidence of long-range transport of these substances to regions where they have never been used or produced and the consequent threats they pose to the environment of the whole globe, the international community has now, at several occasions called for urgent global actions to reduce and eliminate releases of these chemicals. http://irptc.unep.ch/pops/default.html Persistent Organic Pollutants & Reproductive Health The United Nations is currently considering the elimination or reduction of twelve of some of the most damaging chemicals that are Persistent Organic Polutants (POPs) through the formulation of an international, legally binding treaty. Nine of the POPs chemicals under consideration are pesticides that have been extensively used in both developed and developing countries. Although many countries have banned these chemicals, they remain stockpiled, are produced or used illegally, or, because of lenghthy half-lives, they continue to exist in soil, or other environmental media. In Geneva, this paper instructed both government delegates and public interest groups about how these chemicals are particularly injurious to women's bodies.) Lindane (from: A briefing for UNISON prepared by the Pesticides Trust, London, 1999) Lindane - g-HCH [hexachlorocyclohexane], is included in the government "Red List" of dangerous substances. It has been in use as an broad range insecticide for 50 years, long enough to build up a significant body of evidence on its toxic and environmental hazards. It has caused deaths and poisonings in humans and there is authoritative recognition of its long term health effects including carcinogenic effects. It is a serious environmental contaminant and as well as being directly toxic to wildlife. It bio-accumulates along food chains. Scientific and anecdotal evidence links lindane with serious health problems including aplastic anaemia, the birth disorders C.H.A.R.G.E. and breast cancer. (See below). Lindane has been banned or severely restricted in 37 countries. The Advisory Committee on Pesticides in the UK has so far carried out three reviews of lindane and continued to recommend its approval. The Pesticides Trust believes that Lindane should be banned on the basis of existing evidence and as a precaution to avoid further health and environmental problems which are suspected of being caused by lindane. Many other organochlorines which over the years have been linked to major health and environmental problems have been banned or are no longer used. Included in this catalogue are aldrin, dieldrin and endrin which have virtually disappeared, and DDT, heptachlor and toxaphene which have been banned in many countries but are still used quite extensively particularly in some developing countries. Lindane is an organochlorine insecticide that is still in relatively widespread use in developed nations as well as in the third world. It is still in use in treatment against lice and scabies in humans and also against ectoparasites in veterinary treatment. In a control study, Davis et al. reported a statistically significant increase of brain cancer in children following treatment with lindane shampoo. ("Family Pesticide Use and Childhood Brain Cancer", 1993). Veterinary use in sheep can cause contamination of wool, as well of milk and meat. Lindane is also known as g-HCH since it has to be made up of at least 99% of the gamma isomer of hexachlorocyclohexane (HCH). Technical HCH can include varying proportions of alpha, beta, delta and epsilon HCH isomers, but because these have been shown to have serious short and long term health effects, in the UK all HCH products containing less than 99% of the gamma isomer are banned. The organochlorines in general, and lindane in particular, are characterised by their broad spectrum insecticidal activity, long persistence in the environment, and their tendency to bio-accumulate along the food chain. Several cases of human poisoning by lindane have been reported. Children are significantly more susceptible to the toxic effects of lindane. In one case a dose equivalent to 62,5 mg/kg proved fatal, while the LD50 in the rat is above 88mg/kg. In adults, doses above 300 mg/kg ingested orally have proved fatal. Since lindane has been in very widespread use for several decades, its long term health effects have been extensively studied. Included among the reported chronic effects of exposure to lindane are nervous disorders and increased liver weight. The International Agency of Research on Cancer (IARC) has concluded that lindane is a possible human carcinogen (class 2B), and the US EPA has classified it similarly as a class B2/C possible human carcinogen. Key health issues. … Aplastic anaemia. Exposure to lindane has been linked with blood disorders known as blood dyscrasias, and in particular the disorders aplastic anaemia where the formation of platelets and white cells is disrupted. … C.H.A.R.G.E. This condition which involves multiple congenital abnormalities has been linked to exposure of the mothers of CHARGE children to lindane during early pregnancy. A statistically significant proportion of mothers of CHARGE children in the UK were exposed to pesticides in early pregnancy, and one of the most prominent pesticides implicated was lindane.(Blake and others, Child care health and development, 1993, 19, 395-409) … Breast Cancer. Lindane is an endocrine disruptor which is capable of imitating hormones in humans and thereby disrupting the physiological functions which these hormones control. There is a significant body of evidence which suggests that where lindane is used extensively, and particularly where cattle are exposed to it, the incidence of breast cancer is higher. The UK has the highest rate of death from breast cancer in the world, and in Lincolnshire were lindane is used extensively on sugar beet crops, the rate of breast cancer is 40% higher than the national average. (Women Environmental Network, 1994). The presence of lindane in human milk has been reported in countries throughout the world (Moses, Marion, Pesticides and breast cancer, Pesticides News 22, December 1993, 3-5). Environmental effects. Lindane is highly volatile, and when applied to field crops in particular, a high proportion (up to 90%0 of the pesticide enters the atmosphere and is later deposited by rain. Lindane is also leached into surface waters and even into ground water. The International Conference on the Protection of the North Sea agreed to reduce emissions from land, rivers and the atmosphere of number of toxic chemicals including lindane by 50% between 1985 and 1995. In common with other organochlorine pesticides lindane is fat soluble and this contributes to its tendency to bio-accumulate through food chains. Residues have been detected in the kidneys, liver and adipose tissue of a wide variety of wild animals and birds. It is highly toxic to aquatic invertebrates and fish. http://www.earthsummit2002.org/wcaucus Canada has signed and ratified two international agreements to reduce atmospheric emissions of 16 Persistent Organic Pollutants (POPs) and three Heavy Metals (lead, mercury and cadmium). The agreements were negotiated under the auspices of the United Nations Economic Commission for Europe (UN ECE), which includes Canada, the United States, European countries, and countries of the former Soviet Union. The POPs and Heavy Metals Protocols are the first major multinational, legally-binding agreements to place controls on emissions of these hazardous air pollutants. http://www.ec.gc.ca/press/pops1_b_e.htm New Protocol on Persistent Organic Pollutants
Negotiated under the UN Economic Commission for Europe's http://www.epa.gov/oppfead1/international/lrtap2pg.htm Persistent Bioaccumulative Toxins (PBTs)PBT pollutants are chemicals that are toxic, persist in the environment and bioaccumulate in food chains and, thus, pose risks to human health and ecosystems. The challenges remaining on PBT pollutants stem from the fact that they transfer rather easily among air, water, and land, and span boundaries of programs, geography, and generations. EPA Fact SheetPersistent, Bioaccumulative and Toxics Initiative http://www.epa.gov/opptintr/pbt/ Persistent, Bioaccumulative and Toxic Chemicals in Central and Eastern European Countries - State-of-the-art ReportTopical Reports Northwest Guide to PBTs http://www.pprc.org/pprc/pubs/topics/pbt.html Effects of Persistent Toxic Substances on the Environment
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