Fluxes of Al, Fe, Ti, Mn, Pb, Cd, Zn, Ni, Cu, and As in monthly bulk deposition over the Pyrenees (SW Europe): The influence of meteorology on the atmospheric component of trace element cycles and its implications for high mountain lakes

The atmospheric bulk (wet plus dry) deposition of trace elements was measured monthly at Lake Redon (2240 m above sea level, Central Pyrenees, Spain) in 2004-2006. Aluminum, Ti, Fe, Mn, and As were part of the dust carried from the Iberian Peninsula and North Africa: these elements presented low enrichment factors and occurred (except Mn) as particles. Lead, Zn, Cd, and Cu showed a polluting character: their enrichment factors were clearly above those that can be caused by natural fractionation processes; and they were found in a variable, though always large proportion as soluble forms. Nickel had intermediate properties suggesting a balance of both natural and polluting sources. Temporal variations of trace element deposition were related to the prevailing meteorological conditions. Deposition of dust, Pb, Ni, and Cd was higher during the year in which a larger proportion of precipitation came from the Iberian Peninsula-North Africa and followed low-altitude trajectories. On a seasonal scale, deposition of dust and Pb was similarly related to southern air masses occurring during June-November. Possible changes in the general atmospheric circulation patterns as a result of climate change may cause a shift in the proportion of air masses coming from different locations and hence in the fluxes of the elements received by the catchments. Such atmospheric fluxes have caused high concentrations of several trace elements in Pyrenean lake sediments at a level which may be of ecotoxicological relevance.