Riverine inputs and direct direct discharges to Norwegian coastal waters - 2006. OSPAR Commission

Abstract

The report presents results from the 2006 monitoring of 46 Norwegian rivers in accordance with the requirements of the OSPAR Commission. Riverborne inputs of nutrients, suspended particulate matter, total organic carbon, silicate, metals (Cd, Hg, Pb, Cu, Zn, As), PCB7 and the pesticide lindane to Norwegian coastal waters are calculated based on concentration and flow data. In addition, the inputs from rivers not monitored, as well as direct discharges to marine waters along the coast from Sweden in the south to Russia in the north have been estimated. In general, the Norwegian inputs to coastal waters of all RID substances in 2006 may be characterised as being within normal fluctuations as compared to former years. A relatively small increase in nutrient inputs are partly explained by high water discharges in the Skagerrak area in 2006, partly by increased inputs from direct discharges. In terms of metals, an increase in riverine inputs of nickel and a decrease in zinc since 2005 were explained by fluctuations in concentrations and water discharges in the rivers Pasvik and Orkla. Long-term trends (1990-2006) show declines in riverine loads and concentrations of many metals, but this is mainly the result of subsequently lower detection limits. For nutrients and particulate matter, no overall conclusive long-term trends were detected.