Critical loads of cadmium, lead and mercury and their exceedances in Europe

In this chapter information is summarized on the assessment of the risk of impacts of cadmium, lead and mercury emissions and related depositions of these metals, with an emphasis on natural areas in Europe. Depositions are compared to critical loads to identify areas in Europe where critical loads are exceeded. Critical loads of cadmium, lead and mercury were based on (i) computations by 18 Parties to the Convention on Long-range Transboundary Air Pollution (LRTAP) and (ii) computations from available data on soil chemistry, meteorology and land cover for the other Parties. Two target years are considered, i.e. 2010 and 2020. Emissions for these years have been assessed in support of the negotiations for the review and possible revision of the Heavy metal protocol (Aarhus 1998). The relationship between emissions, depositions and critical load exceedances is analysed assuming the implementation of abatement techniques under Current LEgislation in 2010 (CLE2010) and in 2020 under Full Implementation of the Aarhus protocol (FI2020). Comparing the critical loads to atmospheric depositions in these years, shows that cadmium deposition is not a widespread risk in either years, that the computed risk of lead deposition affects about 22 and 16¿% of natural European area in 2010 and 2020, respectively, and that mercury deposition is computed to affect an area of more than 74¿% in both years.