Persistent Organic Pollutants (POPs) in the European Atmosphere

POPs are a group of chemicals which share some specific characteristics that make them of high international concern. Due to their semivolatility, POPs present a widespread distribution being able to reach remote locations and areas after travelling long distances in the atmosphere where they have never been produced nor used. Different chemical families are considered as POPs, such as PCBs, OCPs, PCDD/Fs, PAHs, and, PCNs. In addition, some emerging contaminants are currently considered as candidate POPs, like PBDEs and PFCs. POPs exist in the atmosphere as gases and bound to particles depending on their physico-chemical properties. This affinity to gas or particulate phase is of relevant importance in the processes of POP atmospheric global transport and degradation. POPs are delivered to aquatic and terrestrial ecosystems by atmospheric deposition, air-water interchanges and direct discharges. The general hydrophobic nature of POPs results in high affinity to organic matter andbiota tissues. Consequently, organisms and sediments become final sinks of POPs, due to the low metabolic activity for these compounds and their slow degradation processes in the environment.