Global treaty to phase out "dirty dozen" pollutants.

• Author: Chafe, Zoe
• Position: Environmental Intelligence

A significant international agreement seeking to phase out the use of certain long-lasting chemicals entered into force in May 2004. Stipulations in the Stockholm Convention on Persistent Organic Pollutants will now apply to the 50 countries, including Australia, Canada, France, Brazil, and Tanzania, that have ratified it. The United States has thus far refused to ratify the convention, and will not be required to abide by its rules.

The convention will regulate the production and use of persistent organic pollutants (POPs), highly stable compounds that include the pesticide DDT and industrial by-products, such as dioxin. This class of chemicals is of special concern to the international community because the water-insoluble chemicals can spread long distances, over years or even decades, before they decompose. Twelve chemicals, known as the "dirty dozen," have been selected for priority action, which will include aggressive development of less harmful alternatives.

Global weather patterns have led to the concentration of these chemicals in certain regions, most notably the Canadian Arctic. When animals high in the food chain, such as predatory birds and mammals, consume prey that have been exposed to POPs, the predators accumulate dangerously high levels of the chemicals in their tissues. Members of the Inuit tribe, who live in the Arctic and depend on now contaminated local animals for subsistence, have accumulated such high levels of POPs that the chemicals can now be detected at dangerous levels in their breast milk.

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Workers who apply pesticides, and residents living near POPs production sites, are also at risk for contamination--especially...