以洞庭湖水体中异味物质为研究对象,开展异味物质调查,并结合藻类结构、水质及其营养状况等因素,深入分析洞庭湖异味物质的来源和变化情况.结果表明,DMS(dimethylsulfide,甲硫醚)、DMTS(dimethyltrisulfide,二甲基三硫醚)、β-cyclocitral(β-环柠檬醛)、MIB(2-methylisoborneol,二甲基异冰片)和GSM(geosmin,土嗅素)在全湖广泛存在,其最高质量浓度分别达到500.80、28.80、21.84、14.50和22.40 ng/L.结合与藻类生物量的相关分析发现,直链藻、冠盘藻等硅藻可能是洞庭湖中DMS、DMTS和β-cyclocitral的重要来源,湖区土壤、沉积物中的微生物和死亡分解的藻类是MIB和GSM主要来源.洞庭湖水体绝大部分处于中营养水平,其中东洞庭湖TLI(综合营养状态指数,为48.3)最高,南洞庭湖(为47.3)其次,西洞庭湖(为42.7)最低.异味物质含量和水质的相关分析发现,异味物质质量浓度与TLI、水温、pH 、ρ(DO)、ρ(TN)和ρ(CODMn)显著相关,说明水质对异味物质含量有重要影响.%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.
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