Riverine inputs and direct discharges to Norwegian coastal waters 2005

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Utgave: 2006, Engelsk
TA-nummer: TA-2245
Tittel: Riverine inputs and direct discharges to Norwegian coastal waters 2005

This report presents the results of the 2005 monitoring of riverine and direct discharges to Norwegian coastal waters. The monitoring is part of a joint monitoring programme under the ¿OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic¿. In general, most substances showed a decline, although varying in magnitude, in riverine loads when comparing the loads in 2004 and 2005. It is, however, important to remember that the water quality sampling is done once a month in the main rivers and four times a year in tributaries. This means that little or no account is taken of the water flow variations. The inputs of nutrients, silicate and suspended particulate matter (SPM) in proportion of source (riverine, direct inputs and unmonitored areas; see illustration below) show that the main source for orthophosphate is the direct inputs, related to fish farming. Fish farming comprise the major single source of phosphorus input to the North Sea, Norwegian Sea and Barents Sea sub regions. Totally in Norway, the nutrient load from fish farming contributes to over 60 % of the total phosphorus loading and over 20 % of the total nitrogen load. Only about 20 % of the phosphorus and about 50 % of the nitrogen were inputs from the monitored rivers and tributaries.