In Stockholm in May, 2001, 90 countries signed the Convention on Persistent Organic Pollutants (POPs). The convention has been binding in international law since May 2004.

POPs are characterised by stable chemical structures and longevity. They are suspected of being carcinogenic and damaging to genetic material, and harmful to the immune and nervous systems. POPs include certain pesticides (DDT, dieldrin, etc.), industrial chemicals (PCBs), and dioxins and furans.

POPs have been introduced into the environment in large quantities as pesticides. Because of their stable structures, these chemicals take a very long time to break down. Evaporation in the earth’s warm zones carries them into the atmosphere. From there, global atmospheric currents move them to the colder regions of the earth where, due to condensation, they become concentrated in sensitive ecosystems. Ultimately they are returned to human beings through the food chain.

Certain POPs chemicals are still being produced, sold and used in some countries, such as pesticides used in agricultural production or DDT for preventing malaria. Dioxins and furans are a huge problem: as by-products of many combustion processes, they are released, uncontrolled, into the environment as emissions.

Links:

• POPs secretariat
  www.pops.int
• Convention text
  www.pops.int/convtext/en