Computing atmospheric transport and deposition of heavy metals over Europe: Country budgets for 1985

The Heavy Metal Eulerian Transport (HMET) model has been used to calculate the exchange of As, Cd, Pb and Zn between European countries in 1985. The model was run separately for each emitter country and the computed deposition field was used to calculate the contribution of the emitter to each receptor country. The results of these computations are presented in the form of a country budget matrix for each metal. Accuracy of such computations is dependant on the size and linearity of the numerical method applied to the transport equation. Exchange of heavy metals due to atmospheric transport over Europe is significant. Approximately 30% to 90% of the heavy metals emitted from each country is deposited in other countries. The remaining mass is deposited in European seas, Atlantic Ocean and transported outside the model domain. The largest part of the emission from each country is deposited in the same country. The next largest fraction is transported to the nearest neighbors. The results indicate also a significant long range ransport of heavy metals to the Soviet Union. This is partly justified by the size and location of this receptor country, as well as, the prevailing meteorological conditions in Europe. However, this large transport to USSR is slightly overestimated due to some artificial properties of the numerical method applied to basic model equations. In addition to the country budget, export versus import and emission versus deposition of metals were analyzed for each country. The largest positive difference between export and import was found for Poland, German Federal Republic and Yugoslavia (As, Cd and Zn), and United Kingdom, Italy and Belgium (Pb). The Soviet Union and Czechoslovakia are the countries where import of all metals is significantly larger than export. When emission versus deposition of heavy metals is analyzed, the Soviet Union has much higher emissions than deposition of all metals compared to other European countries.