基于荧光指纹的土门西沟小流域农业面源溯源研究

于2022—2023年采集密云水库的典型农业小流域土门西沟小流域内源样品构建指纹库,采集7、8月河道6个重点断面水样进行三维荧光光谱测定,通过平行因子分析解析小流域氮素来源。结果表明:研究区氮平均质量浓度为7.92 mg/L,主要形态为硝态氮;通过结合荧光激发发射矩阵与平行因子分析共解析出4种荧光组分,主要包括两种类腐殖质组分(C1、C2)及类蛋白组分(C3、C4),C1与农业有机肥施用有关,C2与堆肥有关,C3、C4主要来自农村生活污水或未分解的尿素化肥;研究区农村生活污水荧光指数平均值约为2.16,土壤浸提液荧光指数平均值约为1.83,农村生活污水在8月对农业面源约贡献35%;小流域丰水期水质波动主要与类腐殖质C1、C2组分相关,应对研究区有机肥带来的农业面源给予关注并加强管控。

基于鱼类生物完整性的北京市山区河流生态健康评价

为了掌握北京市山区河流的生态健康状况,采用鱼类生物完整性指数(fish-index of biological integrity,F-IBI)进行了评价。于2021年8月、2022年5月、2022年10月对5条代表性山区河流的11个点位,进行了鱼类种群、水质、生境等调查。构建了鱼类生物完整性评价体系,确定核心指标9项,分别为鱼类总物种数(M1)、Shannon-Wiener多样性指数(M2)、鲤科鱼类占总物种数的百分比(M4)、鳅科鱼类占总物种数的百分比(M5)、底层鱼类百分比(M20)、杂食性鱼类数量百分比(M22)、耐受性鱼类数量百分比(M23)、黏性卵鱼类数量百分比(M26)和鱼类总个体数(M30)。采用比值法对上述核心指标进行赋分,并按照F-IBI得分将河流水生态健康状况划分为5个健康等级。结果显示研究区域河流生态健康状况良好,其中“优”、“良”点位占比为72.7%。通过分析F-IBI值与水质、生境等因素的相关性,发现全盐量、pH与F-IBI存在显著相关,而与水深、距闸坝的距离、溶解氧、透明度、化学需氧量、高锰酸盐指数、氨氮、总磷等不存在显著相关性。河道大量补充再生水会造成F-IBI下降,但是经过适当人工干预措施,如人工湿地,可以有效提升鱼类生物完整性。

Baseflow:Potential Pathway Underlying a High Nitrogen Concentra-tion in a Less-rainy WatershedTaking Chaohe River Basin of China as an Example

Baseflow is one of the major pathways of runoff in hilly areas,and its contributions to surface water resources and pollutant loads cannot be ignored.In this study,based on water quantity and quality data from 1988 to 2019 in hilly and low rainfall watersheds,we focused on the impact of long-term baseflow on nitrogen load using the load allocation based on the baseflow separation method.We also constructed a nitrogen balance model for the Chaohe River Basin of China from 2012 to 2021 to analyze the nitrogen accumulation in the basin.We used the baseflow nitrogen load lag analysis method to study the lag characteristics of the baseflow discharge process and analyzed the response and periodicity of baseflow nitrogen to precipitation and soil accumulation using time delay analysis.The res-ults showed that the contribution rate of baseflow nitrogen reached 69%and showed a slight increasing trend from 1988 to 2019.The ef-fects of changes in precipitation and nitrogen accumulation on the baseflow contribution was observed after 1-2 and 2 yr,respectively.After nitrogen accumulation,it entered the river channel through baseflow,which was already the main and continuous source of nitro-gen in rivers in hilly areas.

兔窦房结切片制作方法的探究和形态学特点的观察

目的:建立兔窦房结(SAN)的快速取材和切片标本制作方法,观察其形态学结构。方法:健康大白兔10只,取其心脏上腔静脉与右心房交界处的界沟组织,常规处理后进行连续切片,采用HE染色法和改良Masson三色染色法显示兔心脏SAN的形态学结构。结果:兔SAN主要位于上腔静脉与右心房界沟的静脉窦侧,SAN区域组织结构较为疏松,染色比较浅淡,主要由P细胞、T细胞、少量心房肌细胞以及包绕细胞的胶原纤维构成,有SAN动脉1~3条。常规HE染色法除细胞核蓝染以外,其余组织均红色,胶原纤维等成分不易观察,改良Masson三色染色中,胶原纤维被苯胺蓝染成蓝色,肌纤维被酸性品红染成红色,胞核呈黑蓝色,对于成分结构复杂的结缔组织分类显示,清晰明了,更好地显示了SAN结构。结论:该取材及染色方法适用于兔SAN切片标本的制作,有助于SAN结构的观察。该方法能够为心脏传导系统的研究提供技术保障,同时能更好地服务教学。

广西沿江某市饮用水水源保护区污水直排口点源污染分析及治理措施研究

本文调查了广西沿江某市饮用水水源保护区范围内污水直排口的数量、种类、特点等,对比分析了国内外水源保护区点源污染治理的常用技术,阐明了研究范围内污水直排口点源污染产生的原因并提出了相应的治理措施。研究发现,该市水源保护区内污水直排口点源污染治理工作,不只是末端污染治理的问题,人们更要结合排污口末端表象,摸排上游排水管网情况,找寻导致污水直排的深层原因。

Legislative Countermeasures for Preventing and Controlling Water Pollution in Water-deficient Regions

The shortage of water resources is severe in Beijing. The shortage of eco-environmental water and the sewage discharge over the environmental capacity are main bottlenecks that restrict the improvement of water environment. The reuse of wastewater could not only reduce the discharge of pollutants,but it could also increase the consumption of eco-environmental water. Therefore the reuse of wastewater is an important approach to improve the water environmental quality. Combined with the formulation process of Regulations of Beijing on Prevention and Control of Water Pollution,the current situations of prevention and control of water pollution in Beijing,the discharge of pollutant,water environmental quality,the population and economic development and water resources and so on were analyzed. And the bottlenecks that restricted the improvement of water environmental quality were found. And the necessity of solving the control of water pollution by reusing the wastewater and ensuring the consumption of eco-environmental water was analyzed from the perspective of the control of water pollution. And some legislative countermeasures were put forward,which provided new ideas for solving the problem of the prevention and control of water pollution and improving the water environmental quality. It was of important reference values for local governments（ especially water-deficient regions） to make relative polices or plans of water pollution control and water environmental protection.