Case Studies on Off-Flavours in Some Norwegian Lakes

Abstract

During the last twenty years, studies on freshwater algae in Norway have documen recent alterations in the trophic nature of several inland waters. Blooms and changes in type of algae were observed. Mass development of algae, e.g., cyano-phytes, upset normal lake metabolism. Objectionable effects on taste and odour in water supplies were reported. The bloom of Oscillatoria bornetii f. tenuis in the Lake Mjøsa - River Glåma system caused several problems in the waterworks Limnological, biological and chemical data from case studies in Norway were summarized, and some practical implications discussed.