Persistent Organic Pollutants (POPs) are organic chemical substances, i.e. molecules based on carbon atoms. These substances have special physico-chemical properties, described below:
- persistent: the substances are difficult to degrade and persist in the environment for long periods;
- bioaccumulative: substances are capable of accumulating in living organisms;
- toxic: exposure to the substance is likely to cause harmful effects on ecosystems and human health (e.g. cancers, birth defects, disruption of the immune and reproductive system in humans);
- mobile over long distances: measurement of high concentrations far from sources of release.
Due to the increase in releases into the environment in recent decades, particularly as a result of human activities, POPs are now widely distributed and have reached regions of the planet where their use has not been recorded, such as the Arctic.
POPs represent a source of contamination of natural environments and also living organisms, which are continuously exposed to these substances for periods of up to several generations, resulting in acute and chronic toxic effects.