Mini-review on river eutrophication and bottom improvement techniques, with special emphasis on the Nakdong River

Water quality in rivers is vital to humans and to maintenance of biotic and ecological integrity.During the Four Major Rivers restoration of South Korea, remarkable attempts have been made to decrease external nutrient loads and moveable weirs were designed to discharge silt that may deposit in pools. However, recently eutrophication of the Nakdong River, which was limited to the lower reaches, is seen to be spreading upstream. The reduction of external nutrient loads to rivers is a long-term goal that is unlikely to lead to reductions in algal blooms for many years because of the time required to implement effective land management strategies. It would therefore be desirable to implement complementary strategies. Regulating the amount of water released is effective at preventing algae blooms in weir pools; so, the relationship between discharge, stratification and bloom formation should be understood in this regard. However, pollutants are likely to accumulate in the riverbed upstream from release points. Thus, to control phosphorus levels, total phosphorus density should be lowered by applying in-river techniques as well. As many ecosystem properties are controlled by multiple processes, simultaneous river bottom improvement techniques, such as combined dissolved oxygen supply and nutrient inactivation, are likely to be effective. The purpose of this review is to present a series of technological approaches that can be used to improve the river bottom area and hence sediment nutrient release, and to illustrate the application of these techniques to the Nakdong River.     

Temporal and spatial variation of nitrogen and phosphorus and eutrophication assessment for a typical arid river—Fuyang River in northern China

Based on water quality surveys over 2 years(July to December,in 2014 and 2015) in a typical arid river in northern China the Xingtai segment of the Fuyang River basin — the variation of nitrogen(N) and phosphorus(P) was analyzed.The extent of water eutrophication of this segment was also assessed using a universal index formula for eutrophic evaluation and a logarithmic power function.The results showed that the average concentration of total N(TN) was 27.2 mg/L(NH_3-N,63.5%),total P(TP) was 2.0 mg/L(solution reactive phosphorus,68.8%).Temporal and spatial variations of N and P in this segment were observed.Concentrations of N and P in the arid season were higher than those in the rainy season.Spatially,the N and P concentrations followed the same trend;i.e.,higher in the city segment than in the suburbs,and decreasing along the river.The water eutrophication in the studied segment reached extremely high levels at all times(eutrophication index ≥76.3).Spatially,its trend was clearly linked with N and P.Water shortage,pollution accumulation and a weak self-purification function are the main reasons for the prominent eutrophication in this segment.     

海河流域河流富营养化程度总体评估

以海河流域2009年地表水水质现状数据为基础,分别运用河流水体富营养化潜势和浮游植物表征河流富营养化水平.结果显示,流域河流水体中富营养盐含量相对较高,河流水体中TN、NH3-N平均含量分别为8.13、4.34 mg·L-1,分别超过《地表水环境质量标准》(GB3838—2002)Ⅴ类限值(2 mg·L-1)4倍、2倍以上.北三河水系(北运河、潮白河、蓟运河)、子牙河水系和海河干流中TN浓度超过9 mg·L-1;海河流域河流水体中TP平均含量为0.87 mg·L-1,超过地表水Ⅴ类限值(0.4 mg·L-1)2倍以上.北三河水系、子牙河水系和黑龙港运东水系水中TP平均含量均超过1.0 mg·L-1.主要河流3%处于中或贫营养,44%处于极富营养化水平,主要分布在北三河水系、子牙河水系和漳卫河水系,表明流域河流总体呈现富营养化状态,平原段河流富营养化严重.河流治理要兼顾耗氧污染控制和营养盐控制,以改善河流水质.     

富营养化水体中内源磷负荷的有效控制

介绍了国内外内源磷控制的主要措施和目前研究现状，并对各种控制措施进行了评价，提出了选择的依据。     

珠江三角洲潮汐河网水环境数学模型评述

对珠江三角洲潮汐河网水环境数学模型研究进行了系统的总结。结果表明：该河网地区一、二、三维水动力与不质数学模型在稳定性、收敛性及模拟精度方面已取得重大进展,而且提出了解决非线性项影响、河断面概化、潮汐动边界、自由表面非恒定运动以及不同维度模型之间的相互连接等难题的有效方法,但同时存在计算机耗时较多的缺点;在潮汐河网随机水质模型、污染物总量优化分配模型和区域水污染控制优化规划模型等方面也开展了探索性的     

Three-dimensional unstructured-mesh eutrophication model and its application to the Xiangxi River, China

The Xiangxi River is one of the main tributaries in the Three Gorges reservoir, with the shortest distance to the Three Gorges Project Dam. Severe and frequent algal bloom events have occurred frequently in the Xiangxi River in recent years. Therefore, the current study develops a three-dimensional unstructured-mesh model to investigate the dynamic process of algal bloom. The developed model comprises three modules, namely, hydrodynamics, nutrient cycles, and phytoplankton ecological dynamics. A number of factors, including hydrodynamic condition, nutrient concentration, temperature, and light illumination, that would affect the evolution of phytoplankton were considered. Moreover, the wave equation was used to solve the free surface fluctuations and vertical Z-coordinates with adjustable layered thicknesses. These values, in turn, are suitable for solving the algal bloom problems that occurred in the river style reservoir that has a complex boundary and dramatically changing hydrodynamic conditions. The comparisons between the modeling results and field data of years 2007 and 2008 indicate that the developed model is capable of simulating the algal bloom process in the Xiangxi River with reasonable accuracy. However, hydrodynamic force and external pollution loads affect the concentrations of nutrients, which, along with the underwater light intensity, could consequently affect phytoplankton evolution. Thus, flow velocity cannot be ignored in the analysis of river algal bloom. Based on the modeling results, building an impounding reservoir and increasing the releasing discharge at appropriate times are effective ways for controlling algal bloom.     

苏南典型河段磷的分布及释放特性研究

通过测定常州典型河段河水和底泥中的磷含量,同时分析了磷在不同底泥颗粒中含量分布的变化,阐述了河流中磷的分布和转移趋势。结果表明:河水中的磷含量通常低于底泥间隙水中的磷含量,但当河流发生富营养化后,底泥中的磷大量向上层水体释放,使得河水中的磷含量不断增加。底泥有效磷与总磷含量之间没有明显相关性,而与底泥间隙水的磷含量之间存在着交换平衡。底泥颗粒以2μm~50μm的粒级为主,即以细砂和粉砂质有机-无机聚合体矿物颗粒为主。磷在底泥颗粒中的含量随着底泥粒径的增大而减少,且粒径越大的颗粒对磷的吸附能力越弱,其中的磷向外释放的可能性越大。     

夏季漓江不同底质类型和沉水植物对底栖动物分布的影响

2012年8月对漓江流域的河床底质、沉水植物、底栖动物和相关环境因子进行了调查,共采集了8个区域,底质类型分为淤泥、卵石、砾石3种底质,植物类型分为无水草(No plant)、亚洲苦草(Vallisneria spiralis)、轮叶黑藻(Hydrilla verticillata)、亚洲苦草+轮叶黑藻(Vallisneria spiralis+Hydrilla verticillata)4种类型,共采集大型底栖动物42种,隶属6纲34属,采用物种相似性、密度和生物量、功能摄食类型、多样性指数等参数,利用CLUSTER、NMDS和单因素方差(One-way ANOVA)分析方法,研究底栖动物在不同区域的差异.不同底质中的底栖动物物种组成、密度、生物量、功能摄食类型相对丰度、Shannon-Wiener指数和Margalef物种丰富度指数都有明显差异,尤其是淤泥底质差异显著(p0.05);在相同底质中,沉水植物的存在使底栖动物物种相似度、生物量、滤食者相对丰度有一定增加,总密度有一定程度的减小;在卵石底质中,轮叶黑藻中的底栖动物总生物量、功能摄食类型相对丰度和亚洲苦草中差异较大;在砾石底质中,亚洲苦草和亚洲苦草+轮叶黑藻中的底栖动物参数差异很小.通过冗余分析(RDA)能较好的解释差异的产生,底质类型对底栖动物分布的影响比沉水植物类型大,而且两者有较强的交互作用.     

Positive remediation on sedimentary P by combination of capping with calcium hydroxide and oxidation with perhydrol

The capping is called passive remediation because the sedimentary P was released and then immobilized by the capping materials. However, the release depends on the environmental conditions. Therefore, a hypothesis was proposed that the oxidant was used to accelerate sedimentary P release and the capping material was used to capture those released P. It is positive remediation to reduce sedimentary P amount. The results show that soluble reactive phosphorus（SRP） concentration in the overlying wat...     

Development and preliminary application of a method to assess river ecological status in the Hai River Basin, north China

The river ecosystem in the Hai River Basin(HRB), an important economic region in China, is seriously degraded. With the aim of river restoration in the HRB, we developed a method to assess the river's ecological status and conducted a preliminary application of the method.The established method was a predictive model, which used macroinvertebrates as indicator organisms. The river's ecological status was determined by calculating the ratio of observed to expected values(O/E). The method included ecoregionalization according to natural factors, and the selection of reference sites based on combinations of habitat quality and macroinvertebrate community. Macroinvertebrate taxa included Insecta,Crustacea, Gastropoda, and Oligochaeta, with 39 families and 95 genera identified in the HRB. The HRB communities were dominated by pollution tolerant taxa, such as Lymnaeidae, Chironomus, Limnodrilus, Glyptotendipes, and Tubifex. The average Shannon–Wiener index was 1.40 ± 0.5, indicating a low biodiversity. In the river length of 3.31 × 10~4 km, 55% of the sites were designated poor, with a bad ecological status. Among nine secondary river systems, Luan and Zi-ya had the best and worst river conditions,respectively. Only 17 reference site groups were selected for river management in the 41 ecoregions examined. This study lays the foundation for river restoration and related research in the HRB, and we anticipate further developments of this novel method.     

Occurrence and formation potential of nitrosamines in river water and ground water along the Songhua River, China

The presence of mutagenic and carcinogenic nitrosamines in water is of great concern. In this study, seven nitrosamines including N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosomethylethylamine (NMEA), N-nitrosopyrrolidine (NPyr), N-nitrosopiperidine (NPip), N-nitrosodi-n-propylamine (NDPA), and N-nitrosodi-n-butyl-amine (NDBA) were investigated in river water and ground water samples collected from 5 representative cities (Jilin, Songyuan, Harbin, Jiamusi and Tongjiang) along the Songhua River. The total concentrations of nitrosamines in ground water were n.d. (not detected) to 60.8 ng/L, NDMA was the most frequently detected nitrosamines in ground water, followed by NDEA and NPip. Relatively high detected frequency and concentrations of NDMA were also observed in river water samples, and the total nitrosamines'' concentration at midstream is always higher than that at upstream and downstream. After 24 hr chlorination, concentration of NDMA, NDBA was obviously increased but NDEA was reduced. Furthermore, UV₂₅₄ showed a better relationship with NDMA-FP rather than dissolved organic carbon (DOC), NH₄-N, and TDN.     

Cell surface-expression of the phosphate-binding protein PstS: System development, characterization, and evaluation for phosphorus removal and recovery

Simultaneous overabundance and scarcity of inorganic phosphate(P_i) is a critical issue driving the development of innovative water/wastewater treatment technologies that not only facilitate Pi removal to prevent eutrophication,but also recover P_i for agricultural reuse.Here,a cell-surface expressed high-affinity phosphate binding protein(PstS) system was developed,and its P_i capture and release potential was evaluated.E.coli was genetically modified to express Ps...     

长江水质评价与沿江产业发展决策

长江干流水质基本良好,攀枝花以上江段属一类水,以下江段绝大部分属二,三类水,但长江干流大中城市江段已出现岸边污染带,达不到三类水要求。长江沿江城市内河均已受到较严重污染,许多内河达不到四、五类水要求。沿江湖泊、城市内湖和自来水取水水源也已受到不同程度污染。长江水质污染与沿江产业发展有密切关系。现仍可在沿江布局新工业和耗水企业,但主要应布局在中上游或稀释能力大的江段;沿江工业发展不宜超速;应搞好区域产业结构调整,长江三角洲地区宜发展高技术产业和高层次第三产业;抓好自来水厂选址工作,严格禁止在水源水附近上游布局污染企业。     

郁江、黔江和浔江广西桂平段水质变化趋势分析

根据2003-2012年水质监测资料,采用秩相关系数法对郁江、黔江和浔江广西桂平段水质变化趋势进行分析。结果表明,黔江和浔江水质呈明显好转趋势;郁江水质呈好转趋势,但不明显。提出了继续加强水污染防治工作的建议。     

洱海西部入湖河流白鹤溪主要污染物时空变化特征分析

为识别入湖河流对洱海水质的影响,2013年9月—2014年8月对洱海西部入湖河流白鹤溪进行了为期1 a的水质监测,研究其主要污染物时空变化特征,估算污染物的入湖负荷量并解析其来源。结果表明:白鹤溪上游区和中游区水质较好,平均为GB 3838—2002《地表水环境质量标准》Ⅲ类水质,下游区和入湖区水质较差,为Ⅳ类水质;白鹤溪CODMn〔(5.10±1.38)mg/L〕、N H 4 + -N浓度〔(0.87±0.76)mg/L〕较低,TN浓度〔(2.81±1.24)mg/L〕、TP浓度〔(0.26±0.12)mg/L〕较高,TN和TP是水质污染的主要指标。白鹤溪主要污染物7—10月入湖负荷量最高,占全年入湖负荷总量的70%左右;其次是12月—翌年2月,占全年入湖负荷总量的18%左右。雨季白鹤溪CODMn、N O 3 - -N浓度显著高于旱季(P<0.05),而N H 4 + -N、TN和TP浓度雨季与旱季没有显著差异,说明CODMn、N O 3 - -N主要来自非点源污染,而N H 4 + -N、TN和TP主要来自点源和非点源污染的共同输入。     

淀浦河水体中氨氮、总氮和总磷污染变化趋势及相关性分析

根据2005年至2011年的监测结果,分析了淀浦河中下游河段的氨氮、总氮和总磷近几年污染变化趋势,并探讨了氨氮、总氮和总磷的相关性。结果表明,淀浦河总氮和总磷的年均浓度均超过水体富营养化的临界浓度,水体富营养化严重。氨氮、总氮和总磷相互之间存在显著相关性,可以通过氨氮、总氮和总磷中某一参数的测定,确定其他两个参数的数值范围,进而确定测定时的稀释倍数,有利于提高监测效率。     

长江中下游地区湖泊富营养化的硅藻指示性属种

在对长江中下游地区45个湖泊表层沉积硅藻属种分布及多次季节性水样调查的基础上,研究了57个常见硅藻属种对总磷指标的生态学特征.利用加权平均回归方法,计算出常见属种对总磷指标响应的生态最佳值及忍耐幅度.根据生态学理论得出,属种Cyclotellameneghiniana、C.atomus、Stephanodiscusparvus、S.minutulus、Naviculasubminiscula是长江中下游湖泊富营养化发生的很好的指示性属种;而Aulacoseiraalpigea、Cyclostephanosdubius、C.tholiformis、C.invisitatus、Stephanodiscushantzschii、Naviculacirtrus、Nitzschiaagnita、N.subacicularis等则是潜在的湖泊富营养化的指示性属种.     

海河流域典型重污染河流滏阳河沉积物氨化和硝化速率研究

为探究海河流域重污染河流高氨氮形成的原因,选择典型重污染河流滏阳河作为研究对象,分析了滏阳河上游邯郸与邢台段和下游石家庄与衡水段水-沉积物界面氨氮的分布特征和沉积物氨化及硝化反应速率.结果表明,滏阳河上覆水和孔隙水中氨氮呈现出下游高于上游的分布特征,其中上覆水氨氮平均浓度为15.72 mg·L~(-1),孔隙水氨氮平均浓度为21.10 mg·L~(-1),氨氮表现为从沉积物向水体扩散.滏阳河全河段表层沉积物氨化速率平均值为4.300μg·g~(-1)·h~(-1),其中上游氨化速率平均值为3.360μg·g~(-1)·h~(-1),下游氨化速率平均值为5.232μg·g~(-1)·h~(-1);滏阳河整体潜在硝化速率处于较低水平,范围在0.001~0.598μg·g~(-1)·h~(-1),平均值为0.152μg·g~(-1)·h~(-1),平均氨化速率约为平均潜在硝化速率的28倍.通过相关性分析可知,氨化速率与沉积物氨氮、总有机氮和全氮显著正相关,与硝氮显著负相关;潜在硝化速率与沉积物硝氮、总有机氮和全氮显著正相关,与总有机碳和碳氮比显著负相关.研究表明,滏阳河沉积物氨化速率远大于潜在硝化速率并形成氨氮累积是造成滏阳河高氨氮现象的重要原因之一,沉积物中累积的氨氮存在通过扩散作用向上覆水释放的风险.     

汀江流域永定段外源污染负荷解析

为明确汀江流域永定段水污染特征并提出有针对性的污染控制对策,采用产排污系数法和入河系数法对汀江流域永定段的外源污染负荷进行了调查分析。结果表明：汀江流域永定段主要污染物指标——化学需氧量（COD _Cr）、氨氮（(NH₄⁺-N）、总磷（TP）的入河量分别为5430.15 t?a^?1、1027.12 t?a^?1、125.03 t?a^?1,各类污染负荷主要来自生活污水、畜禽养殖和农业种植,三者之和占各污染物总负荷的比例超过80%,其他排放源的COD _Cr、氨氮、总磷污染负荷量相对较小。生活污水、畜禽养殖和农业种植是汀江流域永定段水环境污染防治的重点。汀江流域永定段污染排放在空间上呈现较明显的区域差异,各乡镇应针对本区域污染特点有侧重地进行治理。     

淮河流域水污染物排放总量分配的可持续性评价

本文借鉴经济学中反映经济发展状况和贫富差异程度的基尼系数理论,评价淮河流域水污染控制因子COD排放总量在流域四省分配的可持续性,即已确定的总量分配方案是否符合研究区域的经济社会环境状况.本文是在现有环境基尼系数应用上的一种论证性评价,用基尼系数反推已经确定的总量分配方案是否公平合理,为国家污染物总量分配评价提供一定的参考.