Sediment fluxes of polycyclic aromatic hydrocarbons in European high altitude mountain lakes

Polycyclic aromatic hydrocarbons (PAH) were measured in superficial sediments from several high altitude mountain lakes for assessment of contemporary background PAH pollution levels in Europe. The sediments were obtained by gravity coring, and the upper 0-1 cm were analyzed by gas chromatography coupled to mass spectrometry. The parent PAH mixtures are very uniform irrespective of lake location, lake characteristics, and PAH load, corresponding to airborne combustion mixtures refractory to photooxidation and chemical degradation. The sedimentary fluxes are lowest in lake Arresjoen (Arctic area), 6.9 mu g/m(2)yr, between 44 and 150 mu g/m(2)yr in west and central Europe and very high, 960-1700 mu g/m(2)yr, in east Europe. Normalization of these values to TOC reflects a uniform pattern in correspondence with continental influence and east-west distribution. This pattern parallels the annual average atmospheric deposition fluxes of sulfate, pointing to combustion particles as the main way of PAH transport into these high altitude lakes. The lowest PAH/TOC ratios are found in the sites more distant from the continent (4.6-4.9 mu g/g), the westernmost locations constitute another group (Iberian Peninsula, 7.2-7.8 mu g/g), higher values are found in the Alps and Pyrenees (13-17 mu g/g), and the most polluted lakes are found in the Tatra mountains (130 mu g/g).