REMOTE MOUNTAIN LAKES AS INDICATORS OF DIFFUSE ACIDIC AND ORGANIC POLLUTION IN THE IBERIAN PENINSULA (AL-PE 2 STUDIES)

In the framework of the AL . PE 2 project, studies on acidification an d organic pollution in mountain lakes have been conducted in several r anges in the Iberian peninsula: Pyrenees (Northeastern Spain), Sierra de Gredos (Central Spain), Sierra Nevada (Southern Spain) and Sera da Estrela (Central Portugal). These studies focused on water and sedimen t chemistry and organisms (benthic diatoms, zooplankton, aquatic macro invertebrates, and fish) as indicators of acidification. Organic micro pollutants (PAH. PCB, DDE, hexachlorobenzene and others) in lake sedim ents and fish have been studied as traces of atmospheric pollution. Th e Iberian peninsula lakes do not show severe anthropogenic acidificati on pH values are in the range of sensitive lakes, but the levels of ac idic pollutants are low. The status of the organisms surveyed agreed w ith this diagnosis. Pyrenean lakes showed the highest fluxes of organi c pollutants related to fossil fuel combustion, higher pollution-induc ed versus natural acidity ratios,and modeled alkalinity and pH decline s.