Critical Loads of Heavy Metals and their Exceedances

Transcription

1 8 Critical Loads of Heavy Metals and their Exceedances Jaap Slootweg, Jean-Paul Hettelingh, Maximilian Posch 8.1 Critical Loads for cadmium (Cd), lead (Pb) and mercury (Hg) In the context of the revision of the Heavy Metal protocol deposition for 4 scenarios have been calculated, see Chapter 7. To assess the effects these depositions are compared to the critical loads of the European ecosystems. Critical loads of heavy metals have been modelled and mapped with respect to the following effect-end points: 1 = human health effect (drinking water) via terrestrial ecosystem; 2 = human health effect (food quality) via terrestrial ecosystems; 3 = Eco-toxicological effect on terrestrial ecosystems; 4 = Eco-toxicological effect on aquatic ecosystems; 5 = human health effect (food quality) via aquatic ecosystems. Fertilisation of agricultural areas also causes Cd and Pb to enter soil systems, but this is not taken into account in this assessment. For each ecosystem the minimum of the critical loads for is taken. Effect 5 is directly related to the concentration in rainwater. More on the calculations of critical loads can be found in the Mapping Manual (UBA 2004). Following a request from the Woking Group on Effects, a call for data regarding critical loads of heavy metals was issued in 2004, and 18 National Focal Centres of the submitted data (Slootweg 2005). Table 8.1 lists the NFCs that submitted critical load data to the and the effects they addressed. Countries in bold have updated their data in 2006, other submissions are responses to the call in Critical loads for other countries were calculated with the background database for heavy metals (Slootweg 2005). Effects 1 to 4 are based on critical concentrations of the metal in the soil solution. Using a mass balance for the root layer, this concentration is related to the deposition. Status Report

2 Table 8.1 Overview of the country response on the call for critical loads of cadmium, lead and mercury and the 5 effects. Country Country Effect number 1 code Cd Pb Hg Austria AUT x x x x x x x Belarus BLR x x Belgium BEL x x x x x x x x x Bulgaria BGR x x Cyprus CYP x x x x x x Czech Republic CZE x x x Finland FIN x France FRA x x Germany DEU x x x x x x x Italy ITA x x Netherlands NLD x x x x x x Poland POL x x x Russia RUS x x x x Slovakia SVK x x x Sweden SWE x x x x x Switzerland CHE x x x x x Ukraine UKR x x United Kingdom GBR x x Total Figure 8.1 The 5th percentile of the critical loads for Cd(top row), Pb(bottom row) for heath effects, 1 and 2 (left), eco-toxicological effect, 3 and 4 (centre) and combined (right). CL Cd 5 th perc. effects 1 2 < CL Cd 5 th perc. effects 3 4 < CL Cd 5 th perc. effects < MNP/ CL Pb 5 th perc. effects 1 2 < > 5 MNP/ CL Pb 5 th perc. effects 3 4 < > 5 MNP/ CL Pb 5 th perc. effects < > 5 MNP/ MNP/ MNP/ 92 Status Report 2010

3 Figure 8.2 The 5th percentile of the critical loads for Hg for heath effects (1 and 2; top-left), eco-toxicological effects (3 and 4; top-right) and the four effects combined (bottom-left), completed with the critical concentration in rainwater (effect 5; bottom-right). CL Hg 5 th perc. effects 1 2 < > 0.40 CL Hg 5 th perc. effects 3 4 < > 0.40 MNP/ CL Hg 5 th perc. effects < > 0.40 MNP/ CC Hg 5 th perc. effect 5 ng L -1 < > 6 MNP/ MNP/ Critical loads of Pb and Cd for human health (effects 1 and 2), for eco-toxicological effects (3 and 4) and for combined are shown in Figure 8.1. The most sensitive areas are in the south of Russia. For Hg also the critical concentration in rainwater (effect 5) is mapped. For this effect only three countries submitted critical loads, but with many sensitive areas in the north of Russia for Hg; and Fig. 8-2 show the critical loads. 8.2 Average Accumulated Exceedance Average Accumulated Exceedances (AAE) were computed to identify and map areas (grid cells) where atmospheric metal depositions are higher than critical loads. An AAE is the ecosystem area-weighted sum of the individual exceedances (deposition minus critical load, with zero for non-exceedance) of all ecosystems in a grid cell, defined as: AAE = (A 1 Ex 1 + +A n Ex n )/(A 1 + +A n ) where A i is the area of the i-th ecosystem in a grid cell and Ex i its exceedance (i=1,,n) (see also Posch et al., 2001). For the current legislation and the three scenarios the exceeded area of ecosystems and the AAE has been calculated. Tables 8.2, 8.3 and 8.4 show lists the results of the exceedances of Cd, Pb and Hg respectively for all European countries. Blank cells in the table indicate zero values; the value 0.0 indicates a value rounded down to zero. Status Report

4 The share of exceeded area of ecosystems in the European countries for Cd are all below 1 %, with the exception of Bulgaria, which has lower critical loads than other countries in that region, and Macedonia. For Pb the area and size of the exceedances are much higher, only few countries are not exceeded. Hg has the largest exceedances, more that half of the countries have over 90% of their ecosystem area exceeded. Also for effect 5, for which only three countries have submitted data, the critical concentration of Hg is exceeded nearly everywhere (see Table 8.5). The reductions in exceedances in this case are minimal for Option 1 and 2, although they include specific Hg measures. Table 8.2 Exceedance for Cd (g ha 1 a 1 ) for the three scenarios, with the present (CLE 2010) as a reference. Country EcoArea CLE 2010 FI 2020 Opt Opt (km 2 ) Ex.% AAE Ex.% AAE Ex.% AAE Ex.% AAE AL AT BA BE BG BY CH CY CZ DE DK 5280 EE ES FI FR GB GR HR HU IE 4193 IT LT LU 705 LV MD 2227 MK NL NO PL PT RO RU SE SI SK UA YU EU All Status Report 2010

5 Table 8.3 Exceedance for Pb (g ha 1 a 1 ) for the three scenarios, with the present (CLE 2010) as a reference. Country EcoArea CLE 2010 FI 2020 Opt Opt (km 2 ) Ex.% AAE Ex.% AAE Ex.% AAE Ex.% AAE AL AT BA BE BG BY CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IT LT LU LV MD MK NL NO PL PT RO RU SE SI SK UA YU EU All Status Report

6 Table 8.4 Exceedance for Hg (g ha 1 a 1 ) for the three scenarios, with the present (CLE 2010) as a reference. Country EcoArea CLE 2010 FI 2020 Opt Opt (km 2 ) Ex.% AAE Ex.% AAE Ex.% AAE Ex.% AAE AL AT BA BE BG BY CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IT LT LU LV MD MK NL NO PL PT RO RU SE SI SK UA YU EU All Table 8.5 Exceedance of the critical concentration of Hg (ng L 1) for the three scenarios, with the present (CLE 2010) as a reference. Country EcoArea CLE 2010 FI 2020 Opt Opt (km 2 ) Ex.% AAE Ex.% AAE Ex.% AAE Ex.% AAE BE FI SE Status Report 2010

7 The exceedances are also calculated for each EMEP grid. Maps of the Average Accumulated Exceedance (AAE) of Cd, Pb and Hg for current legislation (CLE) in 2010 and for the scenarios with full implementation and the additional Options 1 and 2 (in 2020) are shown in Figures 8.4, 8.5 and 8.6. The exceedances of Pb and Hg are widespread over Europe, but for Cd only a few grids are exceeded, mostly in Russia. Exceedances are reduced by the measures in all scenarios, with largest effects in Option 1, but remain present in most of the grids exceeded at present. Figure 8.4 Exceedance (AAE) of critical loads of Cd for the three scenarios, with the present (CLE 2010) as a reference. The left column shows the exceedance for (1 and 2), the centre column for eco-toxicological effects (3 and 4), and the right column for combined. Cd CLE 2010 Cd CLE 2010 Cd Full Imp Cd Opt Cd Opt Cd Full Imp Cd Opt Cd Opt Cd CLE 2010 Cd Full Imp Cd Opt Cd Opt Status Report

8 Figure 8.5 Exceedance (AAE) of critical loads of Pb for the three scenarios, with the present (CLE 2010) as a reference. The left column shows the exceedance for (1 and 2), the centre column for eco-toxicological effects (3 and 4), and the right column for combined. Pb CLE 2010 Pb CLE 2010 Pb Full Imp g ha-1a-1 Pb Opt Pb Opt ha-1a-1 98 Status Report 2010 g Pb Full Imp Pb Opt Pb Opt ha-1a-1 Pb CLE 2010 Pb Full Imp g Pb Opt Pb Opt

9 Figure 8.6 Exceedance of Hg for the three scenarios, with the present (CLE 2010) as a reference. The left column shows the exceedance for (1 and 2), the centre column for eco-toxicological effects (3 and 4), the right column for unhealthy concentration in fish (effect 5). Hg CLE 2010 Hg CLE 2010 Hg Full Imp g ha-1a-1 ng > 6.00 in fish ng L > 6.00 Hg Opt Hg Opt in fish L-1 Hg Full Imp Hg Opt Hg Opt ha-1a-1 in fish ng L > 6.00 Hg CLE 2010 Hg Full Imp g Hg Opt Hg Opt in fish ng L > 6.00 Status Report

10 8.3 Critical loads of Cd and Pb, re-suspension and exceedances Chapter 7 of this report states that re-suspension is an important part of deposition. Re-suspension is that part of the deposition that originates from other sources than emission sources directly, i.e. is (re-)emitted from soils, in the form of particulate matter (wind erosion). However, in the calculation of critical loads this outflux of re-suspension is not taken into account. Within an effects-based approach three solutions are conceivable. A. Since critical loads do not take re-suspension into account, it should be deducted from the depositions before calculating an exceedance. B. Add the re-emission (at critical level) to the critical load. C. Another way to assess scenarios all-together is to model concentrations of heavy metals in the soil and the soil solution dynamically. This would result in violations rather than exceedances of the critical load, i.e. areas where the concentration in a particular year exceeds the critical limit. References Posch et al., Characterization of Critical Load exceedance in Europe, WASP 130: Slootweg J, Hettelingh J-P, Posch M, Dutchak S, Ilyin I, Critical loads of cadmium, lead and mercury in Europe, Collaborative report by ICP-M&M/ and EMEP/MSCE, MN-ReportP /2005, nl/cce UBA Manual on methodologies and criteria for modelling and mapping critical loads & levels and air pollution effects, risks and trends. UNECE Convention on Long-range Transboundary Air Pollution, Federal Environmental Agency (Umweltbundesamt), Berlin For all options more knowledge on re-suspension is needed to assess the need for measures. Two sources of the metal in the soil can be distinguished, from the parent material (as a mineral), and anthropogenic from either historic depositions or otherwise, for example by fertilizer input. In the context of this study, measures aimed at reducing re-suspension from agricultural sources have not been considered. 100 Status Report 2010