###### Abstract  
The escalating proliferation of cyanobacteria poses significant taste and odor (T/O) challenges, impacting freshwater ecosystems, public health, and water treatment costs. We examined monthly variations in four T/O compounds from September 2011 to August 2012 in Chaohu Lake's eastern drinking water source (DECL). More importantly, we compared the reported T/O occurrence and the related factors in freshwater bodies worldwide. The assessment of T/O issues indicated a severe and widespread problem, with many cases surpassing odor threshold values. Remarkably, China reported the highest frequency and severity of odor-related problems. A temporal analysis revealed variations in odor occurrences within the same water body across different years, emphasizing the need to consider high values in all seasons for water safety. Globally, T/O issues were widespread, demanding attention to variations within the same water body and across different layers. Algae were crucial contributors to odor compounds, necessitating targeted interventions due to diverse odorant sources and properties. A correlation analysis alone lacked definitive answers, emphasizing the essential role of further validation, such as algae isolation. Nutrients are likely to have influenced the T/O, as GSM and MIB correlated positively with nitrate and ammonia nitrogen in DECL, resulting in proposed control recommendations. This study offers recommendations for freshwater ecosystem management and serves as a foundation for future research and management strategies to address T/O challenges. harmful algal blooms (HABs); geosmin; 2-methyl isoborneol; \(\beta\)-cyclocitral; \(\beta\)-ionone +
Footnote †: journal: _toxins_  
0000-0002-0001-6600]E. K. K.  
into a global water issue, with numerous instances documented in studies conducted across China, Japan, Korea, North America, and Europe, thereby underscoring the widespread significance of this concern [16; 17; 18; 19; 20; 21; 22; 23]. Two bicyclic terpenoid compounds, namely, geosmin (trans-1,10-dimethyl-trans-9-decalol, GSM) and 2-methylisoborneol (1,2,7,7-tetramethyl-exo-bicycloheptan-2-ol, MIB), which are renowned for their earthy and musty odors, represent the most frequently identified T/O substances in freshwater bodies globally [24; 25; 26; 27; 28; 29]. Additional investigations have been conducted on alternative T/O compounds associated with cyanobacterial blooms, such as \(\beta\)-cyclodextrin (CYC) and \(\beta\)-ionone (ION). These compounds, stemming from the degradation of \(\beta\)-carotene, exhibit distinctive odors reminiscent of wood, violets, tobacco, and flowers and have been scrutinized in certain water sources [30; 31; 32]. The simultaneous presence of multiple T/O compounds introduces complexity to water quality management and constitutes a significant concern in the context of natural and drinking water in several countries, including China [11; 12; 22; 33; 34; 35]. Given the generally minuscule odor threshold concentrations (OTCs) of T/O compounds, specifically, 4, 15, 19.3, and 7 ng\(\cdot\)L\({}^{-1}\) for GSM, MIB, CYC, and ION, respectively [36], these compounds can be perceptible to humans at trace levels. Notably, China has incorporated GSM and MIB into their drinking water quality standards, establishing current standard values for both compounds at 10 ng\(\cdot\)L\({}^{-1}\)[37]. The resilience of these compounds to oxidation posed a substantial challenge for aquaculture and drinking water facilities in terms of effective monitoring and control [38; 39]. The adoption of advanced treatment methods or a multifaceted approach to eradicate T/O compounds imposes significant financial burdens on water utilities. Therefore, formulating a strategy to prevent the generation of T/O compounds in source water is imperative. As a result, a nuanced comprehension of the foundational information concerning odorants and their interrelation with environmental conditions became imperative for the control and management of odor sources.