Occurrence of earthy–musty taste and odors in the Taihu Lake, China: spatial and seasonal patterns

Abstract

In recent years, the increasing eutrophication of large freshwater lakes in China has resulted in significant algal blooms. The serious taste and odor (T&O) problems that raised from ​algal blooms have been widely studied. To supplement these studies, the types and concentrations of natural earthy–musty T&O compounds in the Taihu Lake were studied in September 2009, January 2010 and September 2010. In the first sampling period, β-ionone and β-cyclocitral were the major odorants, which changed to 2-isopropyl-3-methoxypyrazine (IPMP) and 2-isobutyl-3-methoxypyrazine (IBMP) in September 2010. The occurrence of T&Os was more significant in September (Autumn) than in January (Winter) in both the Zhushan Lake and Meiliang Bay, which are two important regions of the Taihu Lake. However, other regions showed more serious occurrence of T&Os, such as West Coast and South Coast, which was first reported based on the whole lake survey. The concentration of T&Os in the Zhushan Lake was much higher than that in the Meiliang Bay in both January 2010 and September 2010. The reason for the T&O occurrence is suggested by multivariate statistical methods, including principal component analysis and cluster analysis. It is confirmed that the T&O occurrence is more serious in the Taihu Lake due to unaccepted chemicals compared with other eutrophication lakes in China. The initial origins of T&O in the Taihu Lake are also confirmed, and several suggestions on how to control the earthy–musty T&O in lakes or drinking water treatment plants are provided.