Persistent Organic Pollutants (POPs) are chemical substances that persist in the environment, bio-accumulate through the food web, and pose a risk of causing adverse effects to human health and the environment. With the evidence of long-range transport of these substances to regions where they have never been used or produced and the consequent threats they pose to the environment of the whole globe, the international community has now, at several occasions, called for urgent global actions to reduce and eliminate releases of these chemicals, because they are in a nutshell:

* Highly toxic to humans and the environment
* Persistent in the environment, resisting bio-degradation
* Taken up and bio-accumulated in terrestrial and aquatic ecosystems
* Capable of long-range, transboundary atmospheric transport and deposition

In nature these substances affect plant and animal development and growth. They can cause reduced reproductive success, birth defects, behavioral changes and death. They are suspected human carcinogens and disrupt the immune and endocrine systems.

POPs under the Stockholm Convention in Detail: