Unseen Poisins in Asia - a review of persistent organic pollutant levels in South and Southeast Asia and Oceania

Publication - 1 March, 2000
This report draws together published scientific literature on levels of POPs in theenvironment and in animals and humans of Southeast Asia and Oceania.

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Executive summary: Persistent organic pollutants(POPs) are a group of chemicals which are very resistant tonatural breakdown processes and are therefore extremely stable and long-lived. POPs are not only persistent in the environment but many are also highly toxic and build up (bioaccumulate) in the tissues of animals and humans. Most do not occur in nature but aresynthetic chemicals released as a result of anthropogenic activities. Vast amounts ofPOPs have been released into the environment and due to long-distance transport on aircurrents, POPs have become widespread pollutants and now represent a global contamination problem. Certain POPs have been responsible for some catastrophiceffects in wildlife, ranging from interference with sexual characteristics to dramaticpopulation losses. POPs are suspected of causing a broad range of adverse health impactsin humans and there is evidence that current levels of POPs in women in the general population of some countries is sufficient to cause subtle undesirable effects in their babies due to transfer of these contaminants across the placenta and via breast milk.In recent decades, numerous POPs have been produced in large quantities worldwide andmany are still in production and use. Some POPs, such as dioxins and furans, are not produced intentionally but are generated as by-products of many industrial processes including incineration. A few POPs, notably organochlorine pesticides, have been bannedin industrialised countries but due to their persistence, high levels are still found in suchcountries including parts of Southeast Asia and Oceania. In addition, some of theseorganochlorines are still being used both legally and illegally in tropical regions of Southeast Asia for agriculture and public health programs to control pests and vector borne diseases. Indeed it was predicted over 20 years ago that there would be a southwardshift of DDT use from industrialised countries of the Northern Hemisphere to tropicalcountries. Studies on levels of DDT in the global environment show that high levels of DDT are now found in terrestrial and marine environments of tropical Southeast Asia.Research on levels of organochlorines in the environment indicates that a southwardexpansion in the use of chlordane and PCBs into this region has also occurred in recent years. Furthermore, it is predicted that PCB pollution will increase in the tropics as a consequence of inadequate disposal of electrical equipment.This report draws together published scientific literature on levels of POPs in theenvironment and in animals and humans of Southeast Asia and Oceania. The data revealsthe state of contamination for this region of the globe and gives insight into the fate ofPOPs in tropical regions. Studies demonstrate that the current release of POPs in tropicalSoutheast Southeast Asia is not simply a localised problem. High temperatures and heavyrainfall in this region appears to lead to rapid dissipation of POPs to the atmosphere suchthat POPs released in tropical Southeast Asia add to the global problem of POPs contamination.

Num. pages: 63

ISBN: 90-73361-64-8