TILLFÖRSEL AV PETROGENA KOLVÄTEN (PHC) TILL SALTSJÖN OCH ÖSTRA MÄLAREN I STOCKHOLMS LÄN - EN ÖVERSIKTLIG UPPSKATTNING AV KÄLLOR OCH MÄNGDER / The Input of Petroleum Hydrocarbons(PHC) to Saltsjön and Eastern Mälaren in the Province of Stockholm - An Approximate Estimation of Sources and Quantities

The input of petroleum hydrocarbons (PHC) to the coastal waters in the province of Stockholm has been theoretically estimated to 150-630 tons/year. The main quantity originates from land-based discharges. These are transported to the coastal waters directly from municipal waste water treatment plants (20-60 tons/year) and industries (40-145 tons /year) and indirectly from atmospheric fallout (15-85 tons/year), urban runoff (5-25 tons/year) and river and lake outflow (40-125 tons/year). The discharges in connection with ship traffic (“chronic and acute”) are estimated to 25-150 tons/year and from extensive leisure boat traffic to 5-40 tons/year.