Musty Odour Problems in Lake Biwa 1982-1987

Abstract

This paper discusses the results obtained by two research groups investigating the musty odour problem in Lake Biwa during the years 1967 to 1987. The study has shown that the problem is caused by the growth of three species of planktonic blue-green algae in the southern lake. These algae produce as metabolites either 2-methyl-isoborneol (MIB) or geosmin and it is these compounds which give rise to the musty odour. Recently the musty odour problem has expanded from western to eastern part in the southern lake. The occurrence of the problem has also changed from spring to early summer and more recently it has begun to appear also during the autumn months. The maximum concentrations for geosmin and MIB, 1,050 and 860 ng/l, recorded for the lake occurred in the autumn of 1985.