Relationships between odors and algae and water quality in Dongting Lake

The Dongting Lake is the second largest freshwater lake in China. It is for the first time to study on the taste and odor compounds in the lake. Five chemical compounds, dimethylsulfide (DMS), dimethyltrisulfide (DTMS), 2-methylisoborneol (MIB), β-cyclocitral, and geosmin (GSM) were detected and the highest concentrations of these compounds were 500.80, 28.80, 21.84, 14.50, and 22.40 ng/L, respectively. DMS, DMTS and β-cyclocitral were closely related to Melosira and/or Stephanodiscus in Bacillariophyceae. This suggested that these algae probably were the sources of DMS, DMTS, and β-cyclocitral in the Dongting Lake. The particle-bound MIB and GSM were not detected, which suggested that MIB and GSM were probably produced by microorganisms in sediment, the soil around Dongting Lake or the rotten algae. The trophic state of the Dongting Lake is mesotrophication with TLI of three regions between 42.7 and 48.3. The concentrations of these five odors were directly influenced by the water environmental factors