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| | | Organic contaminants and POPs |
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| | Modern industry creates such a massive range of organic pollutants that it is difficult to generalise in any meaningful way as to sources, uses or impacts. The following is a brief summary of some of the major groups of organic pollutants which are of particular concern: | | | Organotin compounds. These, and particularly tributyl tin, are highly effective toxins, even in concentrations that are so small as to be virtually undetectable.
Polychlorinated biphenols (PCBs). A broad family of compounds which are relatively persistent.
Polycylic aromatic hydrocarbons (PAHs). A group of compounds containing aromatic rings. They are released from crude oil, and from the incomplete combustion of oil, wood and coal.
Pesticides. By definition all agricultural pesticides are toxic. A large number, including some of the most widely used over the past 60 years are persistent and have become widely distributed at the global level. These include aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, mirex, toxaphene and lindane (hexachlorocyclohexane, HCH).
Hexachlorobenzene. Used as a pesticide, but also arises from imcomplete combustion at dumpsites
Dioxins and Furans. Known in full as polychlorinated dibenzo-p-dioxins (PCDDs), and heptachlor-polychlorinated dibenzo-furans (PCDFs). These compounds (sometimes collectively known as dioxins) are unintended byproducts arising from certain thermal processes such as waste incineration and by industrial processes involving the use of active chlorine.
| | | | The transport of these compounds to the oceans may be by rivers, but large amounts are also carried in atmospheric pollution. The effects of these compounds are varied. Many are hydrophobic, but are lipid soluble which means that they are readily taken up into the body and accumulate up the food chain. They present considerable problems both in terms of human health and fisheries and for their specific action on individual species. A number, including many pesticides, have direct impacts on the hormone system of many species and are known as endocrine disruptors . Within these compounds there is a group of highly persistent compounds which have been subject to considerable interest, the so-called persistent organic pollutants or POPs. | | | | |
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979 Topics - 5229 Related Knowledge - 11257 Members - 47 Editors |
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