【作者】 胡芳；

【导师】 许振成； 赵学敏；

【作者基本信息】 湖南农业大学 ， 环境工程， 2012， 硕士

【摘要】 东江流域惠州段位于东江中游,其水质对东深供水安全至关重要。多年来,受西枝江、淡水河污染负荷的不利影响,又由于近年来梯级开发、区域经济迅速发展等人为因素影响,水生生态系统受损,水体富营养化程度加重,以湖库污染为代表的藻类增生事件在东江干流频发,给东江供水带来安全隐患。因此,对该河段的富营养化状况进行调查研究,对东江优质水源保护至关重要。项目组于2011年1月开始,每月定期对东江流域惠州段水生态进行调查,研究结果如下：(1)东江流域惠州段污染物以氮(TN、氨氮)、磷(TP)等营养盐和有机污染(BOD5、DO)为主。(2)调查期间,东江干流惠州段、西枝江江河段和淡水河河段分别检出浮游植物129种、120种和103种,浮游植物种类组成均以绿藻最多,硅藻其次,干流藻类细胞密度波动范围为1.46×105cells/L-2.85×107cells/L,西枝江藻类细胞密度波动范围为1.60×105cells/L-1.17×107cells/L,淡水河藻类细胞密度波动范围为7.04×105cells/L~1.36×107cells/L,卵形隐藻为干流全年优势种,该种藻在西枝江河段除7月份不是优势种外,其余各月均占优势。三类水域以东江干流惠州段污染最轻,但干流水体水质空间差异较大,以剑潭库区特别是库区内受西枝江汇入水域污染较为严重。(3)CCA分析表明,PHB、OD5、TP、DO正磷酸盐、NH3-N、CODMn、TN、电导率和亚硝氮对东江于流惠州段浮游植物群落的结构影响较大,pH、CODMn、浊度、SD、DO、硅酸盐和氨氮对西枝江河段浮游植物群落的结构影响较大。(4)东江干流惠州段富营养化状况呈现明显的时空分布特征,剑潭库区内与西枝江交汇下游(D4、D5和D6)为该河段富营养化敏感区域,丰水期初期(3月份和4月份)和夏季(8月份)为敏感区域的敏感时期。西枝江河段富营养化程度以X1和X3采样点最为严重,全年的4月和10月为该河段敏感水域的敏感时期；淡水河河段整体水质处于中富营养化状态,1月、3月、5月和7月的富营养化程度较为严重。(5)运用主成分分析和逐步回归分析,得到以下模型：D4采样点浮游植物细胞密度预测模型为：1g(浮游植物细胞密度)=0.068F2+6.422,Chl.a预测模型为：Chl.a=3.599F2+21.111,其中F2=0.926TN+0.917正磷酸盐+0.885氨氮+0.772电导率+0.465TP+0.424SS-0.420浊度,D5采样点浮游植物细胞密度预测模型为：lg(浮游植物细胞密度)=0.053F1+6.276,Chl.a预测模型为：Chla=4.582F1+20.124,优势种卵形隐藻预测模型为：lg(卵形隐藻细胞密度)=0.082F1+5.681,式中F1=0.966氨氮+0.955TN+0.941电导率+0.900BOD5+0.894SS+0.730DO+0.709硝氮+0.696pH+0.643CODcr-0.492浊度+0.473正磷酸盐。各种预测模型均能用于东江干流水生态风险预测,且以Chl.a预测模型的预测效果最好。(6)针对干流富营养化敏感水域潜在的水生态风险,加大减排力度和深度净化设施建设、加强支流水体的污染控制和生态修复、加强干流水体自身的生态环境保护以及库区水生态监测,对干流水体水质保护意义重大。更多还原

【Abstract】 Huizhou reach of Dongjiang river located in middle reaches, the water quality was very important for water supply. Over the yeas, by the adverse effects of pollution in Xizhi River and Danshui River and because of human factors influence such as cascade development and rapid regional economic development, aquatic ecosystems in Huizhou reach of Dongjiang river damaged, the level of eutrophication was seriously, brought much danger in water supply. Therefore, the investigation on the eutrophication situation of this reach is very important. TO protect the quality of Dongjiang river, surveys on the phytoplankton and aquatic environment factors were carried out every months from January2011, the results of this study were as follows:(1) The main pollutants in Huizhou reach of Dongjiang river were nitrogen (TN, NH3-N), phosphorus (TP) and organic substance(BOD5, DO).(2) Total129,120and103species of phytoplankton were identified in main stream, Xizhi river and Danshui river respectively, which was mainly composed of the Chlorophyta and Bacillariophyta. Average densities of Alga were ranged from2.23×105cells/L to8.04×106cells/L in main stream, and1.60x105cells/L-1.17×107cells/L in Xizhi river,7.04×105cells/L-1.36×107cells/L in Danshui river. Cryptomonas ovata Ehr. was the dominant species in main stream through the year, and was the dominant species in Xizhi river expect July. Although the water quality of main stream was in a light or no pollution state, the spatial difference was evident, pollution in Jiantan reservoir especially waters where Xizhijiang drains into was much more seriously, water quality of Danshui river and Xizhi river was much more seriously than main stream.(3) CCA showed that, the important environmental factors which affected the distribution of phytoplankton of main stream were pH, BOD5, TP, DO, orthophosphate, NH3-N, CODMn, TN, conductivity and NO2-N, while CODMn, turbidity, SD, DO, silicate and ammonia nitrogen in Xizhi river.(4) Temporal and spatial differences in eutrophication is obviously in main stream, Jiantan reservoir where Xizhi river drains into (the D4, D5and D6) was the sensitive waters, early wet season (march and April) and summer (August) were the sensitive periods. X1and X3were the most serious sample sites of Xizhi river, April and October were sensitive periods. The water quality of Danshui river is in mesotrophic, January, March, may and July were sensitive periods in this reach.(5) By using principal component analysis and stepwise regression analysis, we got the following modeles:algae density prediction model of D4:1g (algea density)=0.068F2+6.422, Chl.a prediction model:Chl.a=3.599F2+21.111, F2=0.926TN+0.917PO43-+0.885NH3-N+0.772cond+0.465TP+0.424SS-0.420NTU, the algae density prediction model of D5:1g (algae density)=0.053F1+6.276, Chl.a prediction model:Chla=4.582F1+20.124, density of dominant species prediction model:lg (algal density)=0.082F1+5.681, F1=0.966NH3-N+0.955TN+0.941cond+0.900BOD5+0.894SS+0.730DO+0.709NO3-N+0.696pH+0.643CODCr-0.492NTU+0.473PO43-. All kinds of forecasting model can be used in ecological risk prediction of Dongjiang river, and the models for Chl.a forecasting is the best.(6) Due to the potential ecologic risk of main stream, we should take effective measures as muchas possible, for example, increasing reduction efforts and the construction of deep purification facilities, strengthening the control of tributaries pollution, ecologicalrestoration and water ecological environment monitoring and so on.更多还原