All information on industrial pollution discharged in 2001 was drawn from EPER-Spain records. This information is public, and the records are accessible as a relational database, from the European Commission server . In every case where the geographic WGS84-projection coordinates for the pertinent industrial installation could be imported and incorporated into a Geographic Information System (GIS), these are shown against the entry concerned.
The data were obtained and processed to include all the information necessary for analysis purposes, in three data files, namely, emissions to air, direct to water and indirect to water (via sewage treatment plants). Although there are 4,949 installations affected by the IPPC Act in Spain, the EPER-Spain included only 1,437, which released pollutants that have exceeded the reporting thresholds in 2001. Data were not published for the remaining installations (3,512) because they did not exceed the reporting thresholds for the pollutants, and consequently they are not considered in this study.
Pollutants/Substances were classified into the following groups:
1) Environmental themes: methane, carbon monoxide, carbon dioxide, hydrofluorocarbons, nitrous oxide, ammonia, non-methane volatile organic compounds (NMVOC), nitrogen dioxide, perfluorocarbons, sulphur hexafluoride, sulphur dioxide, nitrogen and phosphorus.
2) Metals and compounds: arsenic, cadmium, chromium, copper, mercury, nickel, lead and zinc.
3) Chlorinated organic substances: dichloroethane-1,2, dichloromethane, chloroalkanes, hexachlorobenzene, hexachlorobutadiene, hexachlorocyclohexane, halogenated organic compounds, dioxins and furans, pentachlorophenol, tetrachloroethylene, tetrachloromethane, trichlorobenzenes, trichloroethane-1,1,1, trichloroethylene and trichloromethane.
4) Other organic compounds: benzene, toluene, ethylbenzene, xylenes, brominated diphenylether, organotin-compounds, polycyclic aromatic hydrocarbons (PAH), phenols and total organic carbon.
5) Other compounds: chlorides, chlorine and inorganic compounds, cyanides, fluorides, fluorine and inorganic compounds, hydrogen cyanide and PM10.
Based on this material, we described the distribution of the number of industries and amounts discharged for each pollutant, as well as emission by pollutant group and the industrial activities associated with each pollutant. Maps of Spain were drawn up, with UTM coordinates being used to plot pollutant foci, and circles with an area proportional to the emission to depict pollution emission values. In order to plot the maps, pollutants classified as group-1, -2A and -2B carcinogens by the International Agency for Research on Cancer (IARC) were selected . Lastly, we compared Spain's percentage emissions to those of European Union countries, focusing on air pollutants for which Spain had some type of emission registered.