Lead, Cadmium and Mercury Transboundary Pollution in 2000

MSC-E/CCC Technical Report 5/2002

I.Ilyin, A.Ryaboshapko, O.Afinogenova, T.Berg, A.-G.Hjellbrekke, D.S.Lee

ABSTRACT

In accordance with the EMEP work-plan for 2002 approved by the Executive Body for the Convention on Long-Range Transboundary Air Pollution the EMEP Centres provide information about monitoring and model assessment of concentrations, depositions and fluxes of lead, cadmium and mercury for the EMEP domain. Monitoring of heavy metals is supervised by Chemical Coordinating Centre (CCC), the model assessment is the responsibility of Meteorological Synthesizing Centre-East (MSC-E). A brief content of the Report is given below.

The first chapter describes measurement results of lead, cadmium and mercury carried out at the EMEP monitoring network.

The second chapter presents data on physical-chemical properties of heavy metals and their behaviour in the atmosphere. The description of a number of physical-chemical processes has been modified in comparison with the previous model version. The refined mercury chemical scheme provided more realistic concentrations in precipitation. In parallel boundary concentrations of lead, cadmium and mercury, the parameterization of dry deposition processes have been refined. The current model version computes metal depositions in accordance with land-use type. Such kind of information can be useful for the comparison of atmospheric depositions with critical loads determined for different ecosystems.

The third chapter is dedicated to anthropogenic and natural emissions. At present the EMEP database contains official emission data for 1990 - 2000 submitted to the UN ECE Secretariat. In the absence of official data expert estimates are used.

The fourth chapter provides computation results for 2000. They involve heavy metal budgets for the EMEP domain as a whole, concentration and deposition fields, estimates of transboundary fluxes between European countries and estimates of loads to seas surrounding Europe. Changes in the obtained results in comparison with 1999 were analysed and the most significant factors influencing these changes have been revealed. First of all among these are changes in emission data. The decline of lead and cadmium emissions as a whole resulted in decreased depositions. The most drastic changes in depositions are noted in countries, in which estimated emissions were substituted by official data. Second, the refinement of meteorological data pre-processing in particular precipitation scheme led to the decrease of precipitation total amount and thereby to reduced lead and cadmium deposition. Mercury depositions also decreased in comparison with 1999 but in this case due to the refined parameterization of dry deposition and emission reduction.

Essential countries-sources of transboundary pollution were identified and the role of indeterminate and national sources was revealed. In Europe as a whole transboundary depositions declined in comparison with 1999.

The comparison of modelling results with available monitoring data showed that in general the model reasonably reproduces European pollution levels.

Basic results of this study are summarized in the section "Conclusion". Annexes provide additional technical information.