高外源性藻类输入的城市河道嗅味物质分布特征及影响因素

Distribution characteristics and influencing factors of odorants in urban rivers with high exogenous algae input

利用顶空固相微萃取-气相色谱/质谱联用(HS-SPME-GC/MS)技术测定梁溪河干流及支浜8个点位水体及沉积物中6种嗅味物质浓度(二甲基二硫醚、二甲基三硫醚、2-甲基异茨醇、土臭素、β-环柠檬醛和β-紫罗兰酮),结合环境因子分析了6种嗅味物质的空间分布特征及其主要影响因素.研究结果表明,梁溪河水体及沉积物中嗅味物质以β-环柠檬醛和2-甲基异茨醇为主,其浓度最高值分别为342.70 ng·L^(-1)和2664.58 ng·kg^(-1).梁溪河水体及沉积物中嗅味物质浓度在干流和支浜中的分布不一致,干流水体高于支浜水体,支浜沉积物高于干流沉积物.影响嗅味物质分布的主要原因可能是蓝藻水华大量输入引起的水体及沉积物营养物质增加及微环境的改变,表现为多种嗅味物质浓度与叶绿素浓度及TOC、TN和N/P呈正相关.由此,本研究为高外源性藻类输入城市河道的治理及异味问题防范提供理论支持.

In this study,six odorants(dimethyl disulfide,dimethyl trisulfide,2-methylisoborneol,geosmin,β-cyclocitral andβ-ionone)from water and sediments at 8 sites of Liangxi River including main stream and branches were investigated,by applying the headspace solid-phase microextraction coupled with gas chromatography/mass spectrometry technology(HS-SPME-GC/MS).The spatial distribution characteristics of six odorants and their main influencing factors were analyzed.The results indicated that the odorants in the water and sediments of the Liangxi River were mainlyβ-cyclicitral and 2-methylisoborneol,with their highest concentrations of 342.70 ng·L^(-1) and 2664.58 ng·kg^(-1),respectively.The distribution of the concentration of odorous substances in water column and sediments of main stream of Liangxi River was inconsistent with that in branches.The concentration of odorous substances in the water column of main stream was higher than that in the water column of branches,and the concentration of odorous substances in the sediments of the tributary was higher than that of the main stream.The main factors affecting the distribution of odorants might be the increase of nutrients in water and sediments and the changes in the microenvironment caused by the large input of cyanobacteria blooms,as evidenced by the positive correlation between the concentration of odorants,and chlorophyll concentration,TOC,TN and N/P.Therefore,our findings provide the theoretical support for the treatment of urban rivers with high exogenous algae input and the prevention of odor problems.