基于流域特性定量评估的东北河流氮磷基准研究

Current nutrient standards for streams and rivers in China are severe imperfect and the reference reaches are lack in regions that are extensively exploited. That is integrated application of reference reaches, historical data, regression models based on watershed characteristics for pre-warning factors and prediction relationship of nutrient and physical-chemical-biological indexes. The regression models based on watershed characteristics for pre-warning factors is also improved. The methods and principles of field investigation, statistical analysis and 3S technology etc. are used to mainly solve the problem that low quantitative level of regression method based on watershed characteristics for pre-warning factors and prediction relationship of nutrient and the physical-chemical-biological indexes of waterbody intensively affected by hydrological pattern under freeze-thaw action. The final aim is to establish a more sound systematic criteria development methods of nitrogen and phosphorus based on quantitative evaluation of watershed characteristics for streams and rivers in the Northeast China, which will provide scientific basis for regional nutrient criteria establishment for streams and rivers.

针对当前我国河流营养物基准极不完善以及流域人类活动影响导致的参照点缺乏的实际问题，采用野外调查、室内分析、3S技术和统计分析等方法与理论，综合运用参照河段法与历史数据法、基于以流域特性为预警因子的回归模型法、营养物与水体物理-化学-生物指标预测关系法，改进以流域特性为预警因子的回归模型，重点解决基于流域特性为预警因子的回归模型方法定量化程度不高、河流营养物与水体物理化学指标预测关系受冻融作用影响下水文格局变化影响强烈的难题，建立科学的基于定量评估流域特性的东北河流氮磷基准制定的方法体系，为我国区域性河流营养物基准制定提供科学依据。

科学制定区域性河流营养物基准是保护河流水质与水生态的关键技术之一。 根据水质和大型底栖无脊椎动物群落结构特征之间的关系，应用多元统计分析技术，确定营养物是清河水系底栖大型无脊椎动物生物受损的主要因子；应用三种化学方法（参照河流频率分布法、全部河流频率分布法、Y-截距法）和一种生物学方法（压力－反应法）评估清河的营养物阈值。参照河流频率分布法和全部河流频率分布法分别基于参照河流和流域全部河流水质数据预先设定的频率分布值评估清河营养物参照状态值；Y－截距法是基于人类活动（土地利用等）对水质影响的回归模型估算营养物的参照状态值；压力－反应法是基于底栖大型无脊椎动物群落特征对河流水质的响应关系估算河流的营养物阈值。三种化学方法估算的营养物阈值为0.750~1.288 mg/L（总氮）和0.035~0.046 mg/L（总磷），生物学方法估算的营养物阈值为1.050~1.655 mg/L（总氮）和0.052~0.101 mg/L (总磷），经过几种化学与生物学方法的相互验证，初步提出清河流域河流总氮与总磷的营养物基准推荐值分别为1.000 mg/L和 0.040 mg/L。研究结果为计算水体中营养物的最大日负荷总量提供科学依据，为流域水生态保护提供科技支撑。