Ambient Levels and Occurrence of Persistent Organic Pollutants (POPs) in the Airshed of a Mediterranean Coastal Lagoon

Abstract

Persistent organic pollutants (POPs) present in the airshed of a given environment may participate in exchange / deposition processes that will determine their inputs to the terrestrial or aquatic ecosystems. In addition, physico-chemical properties of POPs may favour long range atmospheric transport to other areas, even reaching remote zones. It is therefore important to determine the airshed POPs concentration in order to evaluate the potential amounts that may participate in the mentioned processes. Coastal lagoons are characterized by a high biodiversity and intense primary production leading to both ecological and economical considerable importance. Thau lagoon seems to be under intense anthropogenic pressure (urban, industrial, agricultural and shell farming activities). Moreover, indications of an important role of the atmosphere in the accumulation of some POPs families in the lagoon were found in a previous study based on results from a short sampling campaign. In this follow up study we present results on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCB) and polybrominated diphenyl ethers (PBDEs) ambient air concentrations and occurrence from a one year sampling campaign (2007-2008). ¿2,3,7,8-PCDD/Fs total (gas+particulate phases) air concentrations ranged from 67 to 1700 fg m-3, being the higher levels obtained mainly during the winter months. ¿7indicator PCBs total concentrations varied from 11 to 90 pg m-3 whereas ¿DL (dioxin-like)-PCBs ranged from 2 to 8 pg m-3. ¿8 PBDEs total air concentrations varied from 158 to 230 pg m-3. Air masses back trajectories calculations were used to investigate the occurrence of these contaminants in the area. In addition, seasonal variation and congener patterns are also discussed