ABSTRACT
The Baltic Sea is one of the most polluted sea areas in the world, with overall eutrophication and oxygen depletion symptoms and local ecological effects of metals and persistent organic compounds. The drainage basin is shared by 14 countries with a total population of 82 million. A variety of anthropogenic activities have resulted in a nutrient and metal load that must be significantly decreased in order to reach an acceptable level for a sustainable Baltic Sea. International agreements, stating a 50% reduction of the nutrient load during the period 1987 to 1995, have been signed. For some metals, a 70% reduction has been agreed. To achieve these goals a comprehensive action program must be conducted. This means that the load from different sources must be quantified and evaluated to arrive at ecologically sound, reliable and cost-effective measures for reducing pollution from different countries. The Swedish pulp and paper industry annually discharges 400 and 3,100 tonnes of total phosphorus (TP) and total nitrogen (TN), respectively. These quantities represent 10 and 2%, respectively, of the total Swedish nutrient load to the Baltic Sea. The total load from all countries and atmospheric deposition on the sea area is 64,000 tonnes TP y−1 and 1,528,000 tonnes TN y−1 (also including nitrogen fixation). The critical load of phosphorus and nitrogen to the Baltic Sea is estimated to be 30,000 and 600,000 tonnes y−1 respectively. The metal load from the Swedish pulp and paper industry is: zinc 95, cadmium 0.6, copper 7, and lead 4 tonnes y−1. No critical load for metals has been defined. One of the major metal sources for the Baltic Sea is the atmospheric deposition on the sea surface. This means that to control nitrogen and metal loading, comprehensive measures must be taken to decrease emissions to the atmosphere, not only in the drainage area but also worldwide. The load of halogenated organic compounds (analyzed as AOX) from Sweden is significantly lower today (1993) than in previous years. The AOX load from the Swedish pulp and paper industry was ~1,700 tonnes in 1993, compared to ~14,000 tonnes in 1988.
