麦冬对不同程度富营养水的净化和适应性研究

麦冬对不同程度富营养化水的净化能力和适应性是不同的。根据实验结果,在三种处理中麦冬对总氮和总磷的去除率均高于对照,且能通过叶绿素含量、根系活力和叶片SOD、POD活性的变化以适应不同的富营养化条件,故可用于构建稳定的湿地净化系统。

植物气生根在富营养水治理中的应用——以夹竹桃为例

根据植物气生根能吸收水体中氮、磷养分的特性,首次提出了利用气生根处理富营养水的新方法。以夹竹桃为研究对象,在人工模拟的滨水环境(模拟植物种植于堤岸壁或堤岸上,部分枝叶处于水淹状态的情形)中诱导气生根的生长。结果表明:仅需满足夹竹桃的基本生存条件(土壤、阳光、水和温度),77%的夹竹桃能够适应水淹环境并长出较密集的气生根(平均生根率为38%);夹竹桃对水体TP,TN,NH3-N,NO2-N,NO3-N和浊度NTU的实际去除率分别为27.3%,29.1%,17.1%,20.5%,1.6%和0.7%;同时,栽种在岸堤壁或岸堤上的夹竹桃还具有一定水土保持的作用和景观绿化效果。因此,该方法是一种集富营养水净化、水土保持和景观绿化为一体的新型治理富营养水方法。

富营养污水简易集成治理方法研究

以粉煤灰制成空心多功能污水处理材料,用该污水处理材料填充成五级絮凝降解过滤箱,在曝气协同下组成集吸附絮凝过滤与化学降解于一体的富营养水处理系统。在富营养水流量、曝气量分别为60L/h、40L/ m^3·h的工艺条件下,富营养水的可溶性盐、色度、COD_(cr)、BOD_5、氨氮、总磷等主要污染物指标分别降低93%、90%、95%、90%、86%和92%。该富营养水处理系统具有处理效果好、工艺简单和结构紧凑的特点。

人工基质无土栽培萱草对富营养化水的净化研究

利用小型人工基质无土栽培萱草,研究其在轻度和重度富营养水中的生长及净化能力。结果表明,萱草在两种程度的富营养水中生长良好,并能有效地去除TN、TP,尤其在冬季仍能维持一定的净化能力。因此萱草是杭州地区较为适宜的净水植物。

水处理技术在暗纹东方鲀温室养殖中的应用

我们于1998年设计了一套水处理系统,综合利用物理、化学和生物的水处理方法。用于暗纹东方纯养殖。本文对温室养殖暗纹东方纯的水处理技术进行了研究,并对实验结果作了小结。1 材料与方法1.1 场地及水源 本试验在南通龙洋水产有限公司的温室养殖场内进行。龙洋水产公司采用地表下300米深度的深井水养殖。将深井水先进行充分曝气,沉淀,然后作为养殖水源加入养殖池中。

Study on the Changes of Physiological Indexes of Water Spinach in Eutrophication Water

[Objective] Effect of hypoxic water culture on physiological characteristic of water spinach and its hypoxia tolerance were studied.[Method] Water spinach was planted in soil and eutrophication water by means of floating bed,respectively,and the change of physiological indexes including chlorophyll,proline（Pro）,malondialdehyde（MDA）,soluble sugar and soluble protein in water spinach leaves at mature stage was researched,while the hypoxia tolerance of water spinach and the effect of plant density on water spinach growth were discussed in our paper.[Result] In the hypoxic eutrophication water,the content of total chlorophyll,malondialdehyde,soluble sugar and soluble protein in water spinach leaves was lower than that of soil culture,with higher proline content,which showed that water spinach had better tolerance to hypoxic eutrophication water;the higher the plant density,the lower the chlorophyll content in water spinach leaves,and there was no significant effect of plant density on proline and malondialdehyde content,while soluble protein content was higher under high plant density.[Conclusion] The best plant density of water spinach was 66 plants per floating bed with the area of 2 m2,which could provide theoretical basis for the application of water spinach in floating bed.

Analysis on Aquatic Environment of an Artificial Lake and Control Measures to Its Pollution

[Objective] This study aimed to find out effective measures to solve land- scape water eutrophication. [Method] Based on an overview of the urban landscape water characteristics and pollution control situation, taking an example of the artificial lakes in a campus in Xi＇an, we comparatively analyzed the present pollution situation of Xiuyuan Lake and Mingyuan Lake, and provided controlling measures against eutrophication pollution, as well as restoration measures. [Result] All the indicators （TN, TP, Chl-a, NH3-N, CODMn） of the landscape water quality in both Xiuyuan Lake and Mingyuan Lake went severely beyond the Grade IV standards, presenting a state of heavy eutrophication. Nitrogen, phosphorus and other nutrient salts carried by atmospheric precipitation and its runoff, as well as domestic garbage generated by human activities were primary exogenous pollutants of the artificial lakes. And the release of sediment pollutants was endogenous substances causing deterioration of water quality. [Conclusion] This paper presents some measures to control the pollution of artificial lakes, and provides scientific references for the construction, operation and management of artificial lakes, as well as maintenance of aquatic environment.

Toxicity Effect of Hg^(2+) and Cr(VI) on Alga Growth in Eutrophic Water

[ Objective] The toxicity effect of Hg^2＋ and Cr（Ⅵ） on alga growth in eutrophic water was studied to provide reference for biomonitoring and bioremediation of eutrophic water. [ Method ] The mother liquid of alga, which was separated from the eutrophic water, were put into the solutions of Hg^2＋ and Cr（Ⅵ） with different concentrations and their mixture solution, respectively. And the toxicity effect of Hg^2＋ and Cr（Ⅵ） on the growth and propagation of alga in eutrophic water was observed. [ Result] The alga in eutrophic water performed rather sensitive to Cr（Ⅵ） and when its concentration was over 1 mg/L, threre was obvious effect on alga growth. The alga was not very sensitive to Hg^2＋ when its concentration was lower, but its toxicity became stronger and stronger when its concentration increased to some extent and the toxicity effect of Cr（Ⅵ） on alga growth was just on the contrary. When the ion concentration was lower than 10 mg/L, the toxicity of Hg^2＋ on alga was lower than that of Cr（Ⅵ）. When the concentration was over 10 mg/L, the toxicity of Hg^2＋ exceeded that of Cr（Ⅵ）. The toxicity of ion mixture solution of Hg^2＋ and Cr（Ⅵ） had synergism inhibition on alga, which could be performed only when the concentration was over 4 mg/L. [ Conclusion] The toxicity of heavy metal on alga not only related to the alga cell, but also related to the concentration of heavy metal ion.

Controlling effects of forest belts on non-point source pollution of agricultural lands in Taihu Lake area, China

Taihu Lake area is one of the most developed areas in agricultural production. Application of fertilizers and pesticides in large quantities greatly aggravate environmental pollution of this area, and water pollution has worsened to an unbearable condition. Two sampling farms (respectively 1 hm2) under rape-rice rotation and wheat-rice rotation were selected as studied ecosystem and a 5-yr-old Poplar forest and 8-yr-old Metasequoia forest were chosen in the selected areas. By collecting samples of Nitrogen, Phosphorus in water, crops and underground of forest, the transfer and loss of N and P (main water pollutants) in faming ecosystem were studied, and the effects of forest belts on non-point source pollution of agricultural lands was analyzed. The results indicated that the transfer and loss of N and P vary with means of rotation, types of crops and the amount of fertilizer application. Buffering forest belts betweens farmlands and ditches can effectively stop and purify such elements as N and P in soil runoffs, thus controlling non-point source pollution of agricultural lands. When the width ratio of farmland to forest belt is 100 to 40, 50.05% losing N, 29.37% losing P can be absorbed by forest under rape-rice rotation and 30.98% N, 86.73% P can be absorbed by forest under wheat-rice rotation. When the width ratio of farmland to forest belt is 150 to 40, 33.37% losing N, 19.58% losing P can be absorbed by the forest under rape-rice rotation, and under wheat-rice rotation 20.65% lost N and 57.82% lost P can be absorbed. There is only some purification effect when the width ration of farmland to forest belt is 200 to 40. Based on model of buffering forest belts, the width ratio of farmland to forest is determined between 100 to 40 and 150 to 40, because it not only can purify water, but also occupy less farmland. It is suggested that Poplars, with the characteristics of fast-growing and high value, are suitable to be planted as shelter-forest in Taihu Lake Watershed.

A Study on Water Pollution and Bioremediation in Hedi Reservoir

Statistical work and analysis were made based on data of monitored wa- ter quality data in Hedi Reservoir during 2000-2010 and the results show that the content of nutritive salt was higher and water was moderate or light eutrophication. Based on status quo and practical survey research of the Reservoir, the causes for eutrophication deterioration were analyzed and countermeasures were proposed, providing scientific references for sustainable development of Hedi Reservoir.

Mechanisms and assessment of water eutrophication

Water eutrophication has become a worldwide environmental problem in recent years,and understanding the mechanisms of water eutrophication will help for prevention and remediation of water eutrophication.In this paper,recent advances in current status and major mechanisms of water eutrophication,assessment and evaluation criteria,and the influencing factors were reviewed.Water eutrophication in lakes,reservoirs,estuaries and rivers is widespread all over the world and the severity is increasing,especially in the developing countries like China.The assessment of water eutrophication has been advanced from simple individual parameters like total phosphorus,total nitrogen,etc.,to comprehensive indexes like total nutrient status index.The major influencing factors on water eutrophication include nutrient enrichment,hydrodynamics,environmental factors such as temperature,salinity,carbon dioxide,element balance,etc.,and microbial and biodiversity.The occurrence of water eutrophication is actually a complex function of all the possible influencing factors.The mechanisms of algal blooming are not fully understood and need to be further investigated.

Environmental Soil Phosphorus Testing and Phosphorus Release in Taihu Lake,China

A microtiter plate assay (MPA) for soluble reactive phosphorus (SRP) was applied to samples in overlying water and pore water as well as in three forms of environmental soil test phosphorus (P) types: water soluble phosphorus (WSP),diluted calcium chloride extractable phosphorus (PCaCl2), and Olsen-P in the sediments of Taihu Lake, China, where potential P release in response to pH was analyzed. MPA for rapid P analysis was shown to be promising when applied on samples of natural water and sediment extracts. Concentrations of WSP and PCaCl2 in the sediments were much lower than those of Olsen-P. Olsen-P levels in the littoral sediments along the north coast of Meiliang Bay in Taihu Lake (80to 140 mg kg-1) were much higher than those in the mouth of the bay (less than 50 mg kg-1). The risk of P release in the mouth area of Meiliang Bay was lower than that in the north littoral zone with a risk of sediment P release induced by pH increases.

De-eutrophication of effluent wastewater from fish aquaculture by using marine green alga Ulva pertusa

The de-eutrophication abilities and characteristics of Ulva pertusa, a marine green alga, were investigated in Qingdao Yihai Hatchery Center from spring to summer in 2005 by analyzing the dynamic changes in NH4-, NO3-, NO2- as well as the total dissolved inorganic nitrogen （DIN）. The results show that the effluent wastewater produced by fish aquaculture had typical eutrophication levels with an average of 34.3 ~mol L-1 DIN. This level far exceeded the level IV quality of the national seawater standard and could easily lead to phytoplankton blooms in nature if discarded with no treatment. The de-eutrophication abilities of U. pertusa varied greatly and depended mainly on the original eutrophic level the U. pertusa material was derived from. U. pertusa used to living in low DIN conditions had poor DIN removal abilities, while materials cultured in DIN-enriched seawater showed strong de-eutrophication abilities. In other words, the de-eutrophication ability of U. pertusa was evidently induced by high DIN levels. The de-eutrophication capacity of U. pertusa seemed to also be light dependent, because it was weaker in darkness than under illumination. However, no further improvement in the de-eutrophication capacity of U. pertusa was observed once the light intensity exceeded 300 pmolM2 S1. Results of semi-continuous wastewater replacement experiments showed that U. pertusa permanently absorbed nutrients from eutrophicated wastewater at a mean rate of 299 mg/kg fresh weight per day （126 mg/kg DIN during the night, 173 mg/kg in daytime）. Based on the above results, engineered de-eutrophication of wastewater by using a U. pertusa filter system seems feasible. The algal quantity required to purify all the eutrophicated outflow wastewater from the Qingdao Yihai Hatchery Center into oligotrophic level I dean seawater was also estimated using the daily discharged wastewater, the average DIN concentration released and the de-eutrophication capacity of U. pertusa.

Influence of light availability on the specific density,size and sinking loss of Anabaena flos-aquae and Scenedesmus obliquus

Harmful algal blooms in eutrophic waters pose a serious threat to freshwater ecosystems and human health. In-situ light availability control is one of the most commonly used technologies to suppress algae in lakes and reservoirs. To develop a better understanding of the effects of light on algal growth, specific density, colony size and sinking loss, Anabaena flos-aquae(cyanobacteria) and Scenedesmus obliquus(green algae) were evaluated in varying light scenarios. The results showed that the specific density and colony size of these two species varied during growth, and there were obvious differences among the light scenarios. At the end of exponential phase, S. obliquus incubated under light-limited condition maintained a higher specific density and formed larger aggregates, whereas A. flos-aquae formed a longer filament length. Both species exhibited higher sinking loss rates with lower light availability. These results implied that the sinking loss rate was not always constant but should be considered as a variable response to the change of light availability, and in-situ light availability control might result in a significant increase of the sinking loss of algae due to the change of size and specific density, thereby further affecting the algal biomass in the water column.

Assessing the Eutrophication of Shengzhong Reservoir Based on Grey Clustering Method

Reservoir water environment is a grey system. The grey clustering method is applied to assessing the reservoir water enviromnent to establish a relatively complete model suitable for the reservoir eutrophication evaluation and appropriately evaluate the quality of reservoir water, providing evidence for reservoir management. According to China＇s lakes and reservoir eutrophication criteria and the characteristics of China＇s eutrophication, as well as certain evaluation indices, the degree of eutrophication is classified into six categories with the utilization of grey classified whitening weight function to represent the boundaries of classification, to determine the clustering weight and clustering coefficient of each index in grey classifications, and the classification of each clustering object. The comprehensive evaluation of reservoir eutrophication is established on such a foundation, with Sichuan Shengzhong Reservoir as the survey object and the analysis of the data attained by several typical monitoring points there in 2006. It is found that eutrophication of Tiebian Power Generation Station, Guoyuanchang and Dashiqiao Bridge is the heaviest, Tielusi and Qinggangya the second, and Lijiaba the least. The eutrophication of this reservoir is closely relevant to the irrational exploitation in its surrounding areas, especially to the aggravation of the non-point source pollution and the increase of net-culture fishing. Therefore, it is feasible to use grey clustering in environment quality evaluation, and the point lies in the correct division of grey whitening function

Application of an integrated methodology for eutrophication assessment:a case study in the Bohai Sea

An integrated methodology for eutrophication assessment,which integrates both water quality indicators(causative factors) and ecological response indicators(effect factors),is described.It is then applied to rank the eutrophication status of the years 2007 and 2008 in the southwest Bohai Sea.The assessment model identified that north Bohai Bay and west Laizhou Bay were the two areas with the most serious eutrophication problems in the southwest Bohai Sea.In addition,compared to that in the west Laizhou Bay,the eutrophication conditions in the north Bohai Bay was more serious in both years.Eutrophication problems such as harmful algal blooms(HABs) and low dissolved oxygen(DO) events in north Bohai Bay were frequent.The integrated method outmatched the currently used Chinese nutrient index method by definitely identifying areas with the most serious eutrophication problems,while the nutrient index method gave ambiguous results between the two years.Inclusion of both causative factors and effect factors,combining concentration,spatial coverage and frequency of indicators,as well as use of multi-season monitoring datasets in the methodology result in a more accurate,representative and useful assessment.

The decline process and major pathways of Microcystis bloom in Taihu Lake, China

Eutrophication has become a serious concern in many lakes, resulting in cyanobacterial blooms. However, the mechanism and pathways of cyanobacteria decline are less understood. To identify and define the growth and decline of Microcystis blooms in Taihu Lake of China, and to illuminate the destination of surface floating blooms, we investigated the biomass distribution and variations in colony size, morphology, and floating velocity from October 2008 to September 2009. The results showed that the Microcystis bloom declined in response to biomass decrease, colony disaggregation, buoyancy reduction, and increased phytoplankton biodiversity, and these indicative parameters could be applied for recognition of the development phases of the bloom. Three major decline pathways were proposed to describe the bloom decline process, colony disaggregation （Pathway I）, colony settlement （Pathway II）, and cell lysis in colonies （Pathway III）. We proposed a strategy to define the occurrence and decline of Microcystis blooms, to evaluate the survival state under different stress conditions, and to indicate the efficiency of controlling countermeasures against algal blooms.

Does salinity change determine zooplankton variability in the saline Qarun Lake(Egypt)?

Zooplankton and 14 abiotic variables were studied during August 2011 at 10 stations in Lake Qarun, Egypt. Stations with the lowest salinity and highest nutrient concentrations and turbidity were close to the discharge of waters from the El-Bats and E1-Wadi drainage systems. A total of 15 holozooplankton species were identified. The salinity in Lake Qarun increased and fluctuated since 1901：12 g/L in 1901; 8.5 g/L in 1905; 12.0 g/L in 1922; 30.0 g/L in 1985; 38.7 g/L in 1994; 35.3 g/L in 2006, and 33.4 g/L in 2011. The mean concentration of nutrients （nitrate, nitrite and orthophosphate） gradually increased from 35, 0.16 and 0.38 μg/L, respectively, in 1953-1955 to 113, 16.4, and 30.26 μg/L in 2011. From 1999-2003 some decrease of species diversity occurred. Average total zooplankton density was 30 000 ind./m^3 in 1974-1977; 356 125 ind./m^3 in 1989; 534 000 ind./m^3 in 1994-1995; from 965 000 to 1 452 000 ind./m^3 in 2006, and 595 000 ind./m^3 in 2011. A range of long-term summer salinity variability during the last decades was very similar to a range of salinity spatial variability in summer 2011. There is no significant correlation between zooplankton abundance and salinity in spatial and long-term changes. We conclude that salinity fluctuations since at least 1955 did not directly drive the changes of composition and abundance of zooplankton in the lake. A marine community had formed in the lake, and it continues to change. One of the main drivers of this change is a regular introduction and a pressure of alien species on the existent community. Eutrophication also plays an important role. The introduction ofMnemiopsis leidyi, first reported in 2014, may lead to a start of a new stage of the biotic changes in Lake Qarun, when eutrophication and the population dynamics of this ctenophore will be main drivers of the ecosystem change.

Marine ciliate community in relation to eutrophication of coastal waters in the Yellow Sea

We assessed the potential of marine ciliate community as an indicator to coastal water quality using water samples collected from four stations in thc Yellow Sea in the summer 2000. The four stations were characterized by different levels of pollution. The ciliate communities consisted primarily of tintinnids and aloricate ciliates that were 〈30 um. A total of 78 species were classified： 55 species at Station 2, 51 species each at Stations l and 4, and 47 species at Station 3. The mean number of species at each site was 29.2±2.0 （Station 1）, 28.5±2.9 （Station 2）, 27.8±1.7 （Station 3）, and 24.5±2.3 （Station 4）. The abundance was highly variable： 19 331±11 187 ind./L at Station 1, 7 960±5 639 ind./L at Station 2, 29 015±12 999 ind./L at Station 3, and 8 190±4 658 ind./L at Station 4. Our results suggest that neither the simple chemical analysis （e.g. chemical oxygen demand, dissolved inorganic nitrogen, and phosphate） nor the eutrophication/pollution index adequately described the water quality at the four stations. The same was true of the number of species and their abundance, both of which had no correlation with the chemical indices. In contrast, Margalef＇s diversity index values （3.12 at Station 2, 2.89 at Station 1, and 2.64 at Stations 3 and 4） generally discriminated the water quality status of the four stations. The difference in water quality among the stations was strongly supported by the pattern of species richness （i.e. the total number of species） of ciliates at each station. Our evaluation was consistent with the results of long-term water quality monitoring at the four stations. With increasing eutrophication, we observed also a compositional and functional shift in the ciliate assemblages from algivorous oligotrich/choreotrich to nonselective-omnivorous gymnostomatids to bacterivorous-detrivorous scuticociliatids. Thus, eiliates may be used to indicate the coastal water quality status of a given site.

Evaluating lake eutrophication with enhanced thematic mapper data in Wuhan

By analyzing the enhanced thematic mapper (ETM) images of September 1999, and quality observation data for many consecutive years in several parts of the Donghu Lake in Wuhan, China, the authors discovered a good linear relation between grey scale (GS) abstracted from ETM b5, b7 images and eutrophication level of the lakes, and extended the study to eight other major lakes in the area of Wu- han by using lake eutrophication models. Based on the in situ monitoring data, we also evaluated the eu- trophication level of the lakes with modified trophic index method brought by M. Aizaki et al. The results of the two methods showed that the most of the lakes were eutrophicated, and even hyper-eutrophicated in some areas. Six of the 8 lakes had very similar trophic state index (TSI) values. Although two of them differed in TSI value, but within an order, while it was different largely from the one by traditional method. The difference of the results between the two methods might have been due to three causative reasons. First, remote sensing technology reflects the overall status of a certain area corresponding to the ETM images in a certain period, but the modified TSI reflects the annual average values of the monitoring spots. Second, the time the ETM images taken is later than that of in situ data. Third, ETM images are affected by clouds, water depth, and suspended matter. In short, remote sensing result agreed greatly with the in situ monitoring data, indicating that remote sensing technology is feasible and effective for moni- toring and evaluating the lake eutrophication in the Wuhan area and it also can be used to evaluate large-scope lake eutrophication.