El medio ambiente en la minería

121 PER G. BROMAN are traffie, energy produetion, agriculture and municipal waste. These aspects are of importance in detennining the impaet of a particular point source, as the Rónnskar smelter. For example, the smelter previously was a major point source ofcopper discharges. At present, though the annual discharge to water hasbeenbrought down to two tons, the nearbySkellefteRiver alone transports about 16 tons of copper annually. Figure 8 illustrares lhat in today's situatio~ estimated sulphur emissions in excess of the background constitute a build-up that extends only a few kilometers radius from the smelter. Moreover, this background is signifieantly lower than that prevailing in southem Sweden or the continent. By applying a relevant environmental perspective, it can be stated that, with the exception of the very limited local area in which the smelter is still the dominant source of contamination, it is of considerable importance for the region that any new environmental challenges should result in corrective measures that are directed at truly critical sources. 1 can safely state that the marginal rost of sulphur reduction at, for example, a number of large, coal-frred power stations on the continent would be only a fraction of the marginal cost of further reductions at the Rónnskar smelter, while the marginal environmental benefit ofmeasures applied there would be incomparably greater. Similarly, it can be stated that the Baltic Sea's environ– mental condition is to a much greater extent influenced by the impact oflarge, unimproved emission sources than by residual emissions from sources that have largely been corrected, such as the Rónnskar smelter.