Paris Convention. Annual report on direct and riverine inputs to Norwegian coastal weaters during the year 1991. A. Principles, results and discussion

Abstract

Riverine inputs to Norwegian coastal waters from 10 main and 145 tributary rivers have been monitored during 1991. The loading from rivers not monitored as well as direct discharges to marine waters along the coast from Sweden to Russia have been estimated. According to the results, total annual nutrient load to coastal waters from landbased sources, is approximately 3590 tons of phosphours and 8860 tons of nitrogen. About 40 per cent of the phosphorus and 60 per cent of the nitrogen are inputs from the monitored rivers and tributaties. Discharges of heavy metals and micropollutants are also included in the investigation. Most inputs of these substances are low, especially the riverine inputs of Cd, Pb and Hg. Most values of these substances are below the detection limits of the specific analysis, which also in the case for the differen congeners of PCBs. The herbicide lindane is detected in most analyses in small amounts. Total load of this compound is estimated to about 260 kg. The largest yields from heavy metals comprise copper and zinc, with input estimates of 356 and 1040 tons, respectively. Retention in the fjords is not included in the above mentioned values, which in several cases would reduce the actual to open marine waters considerably.