Deposition of PAHs and PCBs in two alpine areas

Mountains are important water reservoirs and contain sensitive ecosystems, which can be polluted by atmospheric contaminants. The emission of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) is leading to widespread distribution and deposition of atmospheric gaseous and/or particle-bound PAHs and PCBs. However, only a few systematic reports have focused on PAH/PCB input processes in mountains. In this study, the PAH/PCB air concentration and deposition (wet/dry) was investigated in two remote alpine areas using passive samplers over two years. Both groups of compounds showed different concentration patterns up to an altitude of 3000 & x202f;m amsl (pg-ng/m(-3)-range), which is caused partly by atmospheric long-range transport. Combustion processes from domestic heating resulted in higher winter PAH emissions (up to ca. 10 times). High PCB evaporation rates in summer from diffuse sources led to higher summer deposition rates. PAH fractionation in air over the winter, favoring low mass PAHs, is probably caused by preferential snow deposition.