产嗅藻类对东太湖某地原水中嗅味物质2-MIB的贡献

针对东太湖某水源地原水中嗅味物质2-甲基异莰醇(2-MIB)浓度过高问题,检测并鉴定原水中藻类分布及组成,考察并建立藻类与2-MIB的相关性,并利用16SrDNA基因测序方法对其中两种主要丝状藻类进行鉴定.结果表明:两个原水取水口及附近养殖区中2-MIB与藻密度呈明显的线性相关(R2>0.85),且颤藻目浮丝藻、泽丝藻以及针杆硅藻等占总藻数量的55%以上.值得注意的是,存在于藻细胞内部的2-MIB比例可达68%,水处理过程中需考虑胞内2-MIB的释放风险.此外,对养殖区周围水质数据分析表明采样点中2-MIB浓度、藻密度、氨氮浓度均和其与离养殖区距离呈负相关性,表明该地区取水口附近的水产养殖可能是导致2-MB偏高的主要原因.

Contribution of algae on theoccurrence of odor and taste compound 2-MIB in drinking water source of East Tai Lake

To figure out the reasonof severe odor problem in the water source of East Taihulake, the algae species and cell densities, as well as their correlationswith 2-MIBconcentration were investigated. Two dominated filamentous algae species in the water were identified according to16S rDNAdetection. The result indicated thatthe algae cell density and the concentration of 2-MIB were of high correlation with R2>0.85.Sometypical odor compounds producer Oscillatoriales (includingthe identified species Limnothrix and Planktothrix) and Synedraaccount for over 55% of the total algae cell numbers. In particular, the intracellular 2-MIB account for 68%of its total concentration, indicating the risk of intracellular 2-MIB release during the water treatment. In addition, the density of algae as well as the concentration of 2-MIB and ammonia nitrogen were decreased withthe increasing distance between sampling points and the aquiculture zone, suggesting that the high concentration of 2-MIB around the intakes wasprobably caused by the aquiculture activities.