External Costs

The external costs resulting from natural and anthropogenic emissions for the business as usual (BAU) scenario are displayed in Figure 1. Effects due to the ingestion pathway, i.e. food supply as well as drinking water consumption, usually occur during a long time span after the pollutant was emitted, thus, the discounting factor for future damages is highly important.



The emission of cadmium, chromium, mercury and nickel cause much less health damages than the contaminants mentioned above. Since effects by inhalation are more or less immediate, they are not influenced by the discouting factor. For mercury damage assessment, there is only a simple equation available, that directly links current European total emissions to current impacts via ingestion of marine water fish, i.e. no discounting factor can be applied. Since the residence of mercury in the atmosphere and bioaccumulation probably is quite significant, its impact via the ingestion pathway for 3% discounting will most likely be less important. The total external costs due to both inhalation and ingestion of these trace elements are shown in Figure 2.



For the assessment of measures that reduce emissions or for the implementation of market-based political instruments to achieve emission reduction, the marginal external costs, that is, the external costs caused by one additional unit of emission in a specific country, are of interest. Although country-specific values are until now only available for the exposure via inhalation, it is planned to calculate the relating values also for the ingestion pathway. The country-specific marginal external costs are shown in Table 1.



Additionally, the marginal costs due to both inhalation and ingestion were calculated for the whole of Europe. It can be seen that arsenic, lead and cadmium lead to the highest marginal external costs while nickel and chromium lead to comparatively small costs. For the special case of mercury only one factor for children's loss of IQ points via fish consumption is given, which is 8.600  € per lost IQ point.



Looking at the individual health endpoints (excluding the one for mercury, which is 8.600 € per kg released due to fish consumption), the exposure to arsenic and lead cause the biggest damages. Figure 4 shows the annual external costs for the BAU scenario for the most important endpoints.