Persistent organic pollutants (POPs)
Intensive modern manufacturing and farming activities have brought into human habitats brand new highly toxic substances and compounds, many of which are exceptionally persistent in the environment.
Persistent organic pollutants (POPs) are chemicals that do not degrade in the environment or degrade slowly. They include a group of highly persistent synthetic compounds which are applied as pesticides in agriculture, used in industry or produced unintentionally as combustion or industrial byproducts. Their presence in the environment is recognized as a worldwide problem as they are persistent, capable of long-range transport in unexpected directions, bioaccumulate in tissues of most living organisms, poisonous for people, animals and plants.
Even very low concentrations of POPs are toxic; due to their ability to fill intercellular spaces they cause many pathological states and processes. Thousands of new compounds are released into the environment annually, although only some of them undergo toxicity tests. Because of globalization, these substances are used more and more in all areas of life of modern society: in agriculture, in the food industry, in medicine, in package material and toy production, etc.
Today POPs are perceived as the immediate threat to human health and the environment. Reliable evidence has been collected linking certain POPs to cancer and other tumors; neurologic and mental disorders, including reduced learning abilities and unwanted character changes; immune disorders, reproductive deficiency and sexual function disorders, shortened lactation in nursing mothers; and such diseases as endometriosis, diabetes, etc.
Concentration of these compounds in human tissues and breast milk causes particular concern. POPs penetrate the growing fetus through the placenta, the infant imbibes them with breast milk. Even ultra-low concentrations (part in a trillion) of POPs can irreversibly damage the infant’s brain and reproductive organs.
The original list of persistent organic pollutants banned by the Stockholm Convention (entered into force in 2004) consisted of 12 chlorine-containing compounds: pesticides (aldrin, dieldrin, chlordane, endrin, mirex, heptachlor, hexachlorbenzene, toxaphene, DDT); industrial chemicals (polychlorinated biphenils) and byproducts (polychlorinated dibenzodioxins and polychlorinated dibenzofurans).
At the Fourth Conference of the Parties to the Stockholm Convention (May 4-8, 2009) 9 new substances were added to the list of twelve POPs: chlordecone, pentachlorobenzene, lindane, alfa-hexachlorocyclohexane, beta-hexachlorocyclohexane, hexabromobiphenyl, pentabromodiphenyl ether, octabromodiphenyl ether; perfluorooctane sulfonate.