Source-receptor relationships for heavy metals in the European atmosphere

Atmospheric concentrations of heavy metals (HMs), in particular As, Cd, Cu, Pb and Zn, were studied in an effort to contribute to the understanding of European source-receptor relationships. A comparison was made between the ambient concentrations measured at 11 background aerosol monitoring station s (in Denmark, the Czech Republic, Finland. Norway and Sweden) and the corr esponding HM concentrations estimated by the Heavy Metals Eulerian Transpor t (HMET) meteorological dispersion model. The collected samples which were analysed with Particle Induced X-ray Emission analysis (PIXE) except the Fi nnish samples which were analysed with Inductively Coupled Plasma - Mass Sp ectrometry. (ICP-MS). The available data covers the period 1985-1994. The c omparison showed that the European emissions of As, Cd and Pb seem to be fa irly well estimated. On the other hand, the European Zn emissions are under estimated by a factor of 3 or more, while the Cu emissions appear to be sli ghtly overestimated. The HMET dispersion model also made it possible to sel ect occasions for which the sampling sites had a substantial contribution o f HM from the highly polluted ''Black Triangle" region (on the borders betw een the Czech Republic, Poland and Germany). The time evolution of the sour ces of HMs within this source region could be studied by applying various s tatistical receptor models on the extensive data set from two Danish statio ns, Keldsnor and Tange, covering the period 1985-1994. Four source types we re clearly discerned throughout the 10 year time period. These sources were : soil dust: sea spray, general combustion and oil combustion. The strong t ime-dependence observed for the contribution from the Black Triangle region emphasizes the importance of keeping the emission inventories continuously updated if HMs deposition calculations and HMs emissions reduction protoco ls are to be based on dispersion modelling approaches. (C) 1999 Elsevier Sc ience B.V. All rights reserved.