Evaluation of Transboundary Transport of Heavy Metals in 1999
Trend Analysis

EMEP Report 3/2001

I.Ilyin, A.Ryaboshapko, O.Afinogenova, T.Berg; A.-G.Hjellbrekke

ABSTRACT

This report provides the results of monitoring and mathematical simulation of the transport and depositions of lead, cadmium and mercury for 1999 as well as the analysis of trends in concentrations and depositions during the 90-s.

Chapter one of the report provides information about the input of lead, cadmium and mercury to the atmosphere from different natural and anthropogenic sources.

Chapter two summarizes monitoring data on heavy metals in air and atmospheric precipitation. Chemical Co-ordinating Centre continued the advancement of the relevant database. At present the database includes measurement data from the late 80-s to 1999 recorded within the framework of EMEP and by other international and national programmes.

Chapter three describes a general structure of the model for calculating the long-range airborne transport of heavy metals and their depositions (MSCE-HM). The model domain covers entire Europe and adjacent regions of the Atlantic, the Arctic, Asia and Africa. The model is a regional one of an Eulerian type with spatial resolution 50x50 km. Along the vertical the model encompasses the boundary layer and a part of the free troposphere up to 4 km height.

Chapter four is dedicated to calculations of long-term trends of concentrations and depositions from the atmosphere of lead and cadmium during the 90-s. Long-term trends allow revealing the most characteristic peculiarities of variations of atmospheric load on the environment.

Chapter five describes the results of the comparison of calculated and measured data for 1999 on the base of statistical processing. Such a comparison gives the idea on the extent of reliability of model results.

The chapter also describes the results of modelling the concentrations, depositions and transboundary fluxes of lead, cadmium and mercury in 1999. The calculation results are represented by maps of concentrations and depositions of the considered metals for the whole EMEP region.

On the base of the prepared emission scenario in Chapter six principal items of lead, cadmium and mercury atmospheric budgets are estimated for the whole EMEP region. It is demonstrated that in the case of lead and cadmium the input due to emissions and inflow through the domain boundaries to the region prevails over depositions within the region area. At the same time the bulk of anthropogenic emissions are deposited within the region. The existing export is partially compensated by the import across the region borders from global sources. For mercury the situation is more complicated. The short-lived forms of oxidized mercury deposits within the region whereas long-lived elemental mercury from European sources is involved into its global cycle.

The situation in individual countries may differ essentially from the regional pattern depending upon geographical position of a country, its size, emission intensity on its own territory and in neighboring countries. The input to heavy metal depositions from both own and transboundary sources are calculated for each country. Besides depositions resulted from natural and transcontinental sources are also estimated. The comprehensive information about transboundary pollution is represented as "sources-receptors" matrix (Annex J). The matrix evidences that that for many countries the input of transboundary pollution can exceed 50%.

The contribution of natural and globally distributed sources is very important for mercury.

Regional seas - the Baltic Sea, the North Sea, the Mediterranean and the Black Seas - are distinguished in calculations as individual receptors. As a contribution of EMEP to relevant Conventions on prevention of sea pollution atmospheric fluxes to the sea basins have been calculated.

The final section of the report provides conclusions of the work undertaken. Annexes A - E illustrate the results of heavy metal monitoring at the EMEP stations in 1999. There also are given matrices of "country-to-country" mutual effect in regard to heavy metal depositions in 1999 (Annexes J). Annex K on the example of Slovakia provides detailed information about "export" and "import" of depositions, dynamics of emission trends during the last decade, comparison of calculated and measured values for 1999.