UNSEEN POISONS IN ASIA

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• Persistent organic pollutants (POPs) are a group of chemicals, which are very resistant to natural breakdown processes – therefore called persistent. Many POPs are also highly toxic and build up (bioaccumulate) in the tissues of animals and humans.

• Most POPs do not occur in nature but are synthetic chemicals released as a result of human activities. Vast amounts of them have been released into the environment and due to long-distance transport on air currents, become widespread pollutants now representing a global contamination problem.

• Certain POPs have been responsible for some catastrophic effects in wildlife, ranging from interference with sexual characteristics to dramatic population losses.

• Some POPs have been highlighted by national and international organisations as being chemicals of concern. For instance, the United Nations Environment Program (UNEP) has listed certain POPs, for elimination via a global treaty, which is presently being negotiated by over 100 governments.

• The UNEP list notes 12 organochlorines – known as the dirty dozen. They contaminate the environment and have potentially toxic effects. They are the dioxins and furans, (produced as unintentional by-products of combustion and processes involving the manufacture, use and disposal of organochlorines); PCBs, (industrial chemicals that have been banned but are still released to the environment in significant amounts from old sources & by-products from some industrial process); HCB (used as a pesticide and 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. Use of these organochlorine pesticides is banned or is severely restricted in most countries, but not in all. Most research on POPs is limited to a few of these chemicals only.

• There are numerous other POPs of great concern. These include pentachlorophenol, brominated flame retardants, HCH isomers - such as the organochlorine pesticide lindane, ), organotin compounds (for example, used as anti-fouling agents for ships), short chained chlorinated paraffins (, used in cutting oils and lubricants).

• Many POPs become incorporated into food webs and ecosystems. They accumulate and persist in the fatty tissues of animals and humans because they are soluble in fats and are not easily broken down in the body. Even low environmental levels of POPs can lead to high levels in the body tissues of animals and humans. Asia like the rest of the globe has not escaped these impacts.

• Levels of DDT were found to be high in tropical Southeast Asia. The literature showed that in air and seawater, the concentrations of DDT were higher in the Bay of Bengal, Arabian Sea, East China Sea and South China Sea compared to other oceans such as the North Atlantic and the Southern ocean. The results imply the continued use of DDT some South- South East Asia countries

• It is well known that DDT is still used in India. The use of DDT in China has also been suggested although its production was officially ceased in 1983. A particularly high level of DDT in air (1000 pg/m3) was found in the Arabian Sea, located off the East coast of India. By contrast, in the Southern Ocean (located around Antarctica) and eastern Indian Ocean (to the west of Australia) levels of DDT were relatively low.

• Global studies of levels of chlordane have implicated industrialised countries in the Northern Hemisphere as emission sources of this pesticide although results outlined in this report also suggested current sources around tropical South - Southeast Asia.

• PCBs have previously been associated with industrialised countries but the distribution of PCBs in seawater was uniform for the Northern and Southern Hemisphere. This is suggestive of the expansion of PCB usage to Asia during the 1980s and hence similar levels of contamination.

• DDT was found to be the predominant organochlorine compounds in fish from tropical Southeast Asia.

• Other organochlorine compounds were lower in fish from tropical South- Southeast Asia than more temperate regions. For instance, levels of PCBs in fish were higher for the industrialised countries of Australia and Japan and levels of chlordane and HCB were higher around Australia than other South- Southeast Asian countries.

• HCH compounds that were highest in fish from around India, indicating the extensive use of HCH

• A similar distribution pattern of POPs from tropical South - Southeast Asia was found in marine mammals as in fish in that levels of organochlorines were lower in animals from tropical waters than in those from temperate waters.

• DDT was elevated in tropical marine mammals of South-Southeast Asia at levels similar to those temperate waters . Marine mammals, dolphins and whales assessed from seas around Japan, Hong Kong, India and the Philippines showed levels which could be considered high and of concern with regard to potential toxicity.

• A study on organochlorines in the Indo-Pacific hump backed dolphin and finless porpoise collected from Hong Kong coastal waters between 1993 and 1997 suggested that the relatively high levels of DDT in the hump backed dolphin and finless porpoise are related to the usage of DDT in Hong Kong until 1989. In addition, results of the levels of DDE, the major breakdown product of DDT, compared to DDT levels was indicative of recent input of DDTs in the Hong Kong ecosystem.

• Highest levels of organotins, (often used in ship paints)were evident in marine mammals from coastal waters of industrialised countries particularly Japan.

• Levels of DDT were particularly high in India and some areas of Vietnam suggesting the continued use of this compound in these countries. By comparison, levels of DDT in Thailand, Indonesia, Malaysia and Taiwan were low.

• Levels of HCH were found to be very high in India and by comparison levels were lower in Taiwan, Vietnam and Thailand.

• Levels of dioxins and furans were found to be highest in industrialised countries of South - Southeast Asia including Japan and Taiwan most likely due to incineration and past pesticide uses. Sporadic high levels of PCBs in Vietnam were found possibly as a result of contamination from old warfare activities.

• In air and surface waters, levels of DDT and HCH were generally higher in tropical Southeast Asia (compared to other regions of South - Southeast Asia and Oceania)

• For air, the highest levels of HCH were found in India and Vietnam probably due to use for vector control. Similarly, DDT was elevated in cities in India, Thailand, Vietnam and the Solomon Islands most likely due to its use for control of malaria-carry mosquitoes.

• Research suggested the significant use of chlordane in tropical South and Southeast Asia, particularly in cities in India and Thailand. Chlordane was only recently banned in Thailand.

• PCBs were found to be uniformly distributed in rivers across South-Southeast Asia and Oceania which reflects the southward migration of the use of these compounds to less industrialised countries of tropical Southeast Asia.

• Organochlorines, including DDT and HCH, in sediments of rivers and estuaries were more uniformly distributed across South East Southeast Asia and Oceania than levels in air and surface waters. This difference has been attributed to the rapid evaporation of organochlorines from water bodies in tropical areas which has the effect of protecting sediments

• Levels of DDT in human tissue were highest in Cambodia, India, Thailand and Vietnam reflecting the use of DDT in tropical South -Southeast Asia. (Comparatively low levels were found in Australia and Japan where DDT has been banned for some years. )

• Extremely high levels of HCH were evident in India and China (reflecting its widespread use in these countries).

• HCB, chlordane and dieldrin were significantly higher in Australia than Thailand and Vietnam.

• Levels of dioxin and furans in human tissues were higher in more industrialised countries including Japan and New Zealand than tropical Southeast Asian countries.

• In South of Vietnam where high levels still persist in human tissues as a consequence of the spraying of Agent Orange, a herbicide contaminated with PCDD/Fs, during the war.

• Studies reviewed in the report demonstrate that the current release of POPs in tropical South- Southeast Asia is not simply a localised problem. High temperatures and heavy rainfall in this region appears to lead to rapid dissipation of POPs to the atmosphere such that POPs released in tropical South -Southeast Asia add to the global problem of POPs contamination.

• For example, semivolatile and persistent POPs such as HCB and HCH appear to be gradually redistributed from tropical point sources to colder regions on a global scale. In the marine environment, it has been suggested that chlordanes and PCBs are likely to disperse to remote oceans through the ocean atmosphere whereas DDTs are less transportable through the ocean atmosphere and are rapidly absorbed in the water bodies close to the emission source.

• There are large gaps in the scientific data on levels of POPs in the environment of South -Southeast Asia and Oceania, most is restricted to investigating levels of a few organochlorines with little or no data on other POPs such as the brominated flame retardants.

• Research on levels of dioxins and furans in the marine environment is extremely sparse and data on PCDD/Fs in the terrestrial environment are also very limited. This crucial gap in the data needs to be fully characterised and remedied.

• The production and use of all POPs, and human activities that lead to the generation of POPs, must be phased out at an international and, ultimately, at a global level.
• This must be achieved through the substitution of POPs (or the processes and materials which generate them) with non-hazardous alternatives.

• Industry and agriculture must pursue clean production technologies and manufacture clean products, recognising that the only way to prevent releases of POPs into the environment is to avoid their production and use.
• As a matter of urgency, action must be taken to stop production, and eliminate all discharges, emissions and losses of those chemicals prioritised for action by UNEP.
• Presume that all chemicals are hazardous until demonstrated otherwise, i.e. until hazard identification is completed, or in those instances where hazard identification is limited by lack of information, chemicals must be assumed to present hazards of unknown proportions.
• Ultimately, measures to eliminate releases of POPs and other hazardous substances to the environment will need to be taken both at a regional basis and on a global basis, because chemical contamination of the environment is a global problem and chemicals do not respect national boundaries.