Persistent Organic Pollutants (POPs) are the chemicals that can remain without undergoing degradation in the environment for a long time (persist), be transported long distances, accumulate in living organisms fatty tissues and pose a high risk on environment and human health. It is known that these chemicals are identified as hazardous not only nationwide but also worldwide since they are subjected to long range transport and can even be detected in areas which none of these chemicals are produced or used.

POPs are unintentionally produced hazardous chemicals resulting from conventionally manufactured pesticides, industrial chemicals and industrial activities.

Before all, POPs are carbon based compounds. The carbon chain is generally surrounded with hydrogen and oxygen atoms, as well as such halogens as chlorine and bromine. Many known POPs belong in the organochlorinated chemicals category (i.e. DDT, aldrin, endrin, chlordane), due to the fact that the chemical industry relies heavily on chlorine with numerous structural possibilities.

Secondly, POPs have a structure that is not breakable or degradable in the natural environment, which is why, they permanently accumulate in the environment through long periods of time, lasting decades. These compounds, which are also biologically persistent, persist for prolonged periods of time in adipose tissues of animals as they possess a fat-soluble character, and may accumulate at high concentrations especially in such predators as eagles and humans, that stand on top of the food chain, as they can enter into food chains easily.

Thirdly, due to their bio-accumulative character, POPs are chronically toxic and may lead to serious persistent health problems on humans and wildlife. Although the evidence of the damages caused by POPs are more frequently observable in animals, they play a role in liver damage, immune and reproductive system disorders in humans, in addition to causing deaths by adversely affecting child growth.

Finally, POPs may travel long distances by means of water waves, evaporation cycles and accumulation. Evaporating at hot temperature extremes, KOKs may as well reach at high altitudes and exhibit an accumulating character especially in polar regions, by gaining density, at lower temperatures.

They are a subject of broad international interest on the global and regional scales. The global international agreement – Stockholm Convention on Persistent Organic Pollutants (SC) – is a global treaty focused on the protection of human and environment against this group of harmful chemicals. Very important regional activities are connected with the Convention on Long Range Transboundary Air Pollution (CRLTAP) of the United Nation Economic Commission for Europe (UN ECE) and its POPs Protocol. Both conventions are included the chemical legislation of European Union.

The aim of the Stockholm Convention and the CRLTAP/POPs Protocol is to evaluate the problems related to the substances named persistent organic pollutants (POPs) or the substances having the same characteristics. These substances classified are classifies Persistent Organic Pollutants because of the characteristics listed below:

· Toxic effects on living organisms (especially as a reason for endocrine disruption).
· Accumulating in fatty (adipose) tissue in organisms,
· Persistency (because of the stable structure, resist to undergo any photolytic, chemical and biological reactions),
· Semi-volatile characteristics (therefore, POPs are subject of long range transport and posing a global environmental problem

The List of SC and CRLTAP Persistent Organic Pollutants

Candidate POPs of SC and CRLTAP