基于无人机高光谱和BP神经网络的城市水体污染监测

我国大多数流域存在不同程度的水体污染,城市水体污染防治与监测是一项艰巨而漫长的任务,而传统水质监测和卫星遥感方法在水体面积较大、水流运动不稳定、周边地形复杂的河流或城市湖泊的水质监测表现为适用性差、准确度低。基于无人机的高光谱遥感技术具有覆盖范围广、数据获取快速等特点,对城市水体污染监测具有一定的应用价值。以珠海市城市水域为研究对象、无人机高光谱数据为数据源,利用线性回归模型和BP (Back Propagation) 神经网络模型方法,分别建立了波段组合反射率与水体叶绿素a、氨氮和磷酸盐3种水质指标之间的最优反演模型,并通过实际样品验证了该模型在城市水体中的适用性。该研究结果不仅为大数据驱动的水质分析提供了重要的技术支持,也为无人机技术应用于城市水体污染程度评价和动态监测提供新方法。     

改良系统成熟度法定量评估污水LOT技术应用潜力——以水专项及相关技术组合为例

随着污水处理满足再生水品质的需求日益提升,对污水中污染物的去除也逐渐向极限技术 (LOT) 发展,亟需探索适合我国国情的技术选择方式。基于现有技术成熟度法 (TRL) 通过算法矩阵构造改良的集成系统成熟度 (SRL) 评价法,对依托“十一五”、“十二五”和“十三五”期间国家水体污染控制与治理科技重大专项相关课题的LOT备选技术、组合及国内外其他满足LOT备选技术组合,进行综合定量评估,梳理我国LOT技术发展现状、并筛选出12项LOT备选技术组合。其中,“A²O+反硝化深床滤池技术”、“A²O+MBBR+混凝沉淀技术”、“A²O+活性自持深度脱氮技术+BAF技术”的SRL可达0.8~1,达到生产、操作和维护阶段,可直接进行生产应用并面向市场产生较高应用效益,但3项技术组合的TN、TP单位质量去除成本较高,其核心处理功能工艺主要为传统反应器类技术。大部分单项技术TRL的等级大于7,改良SRL为0.6~0.8,处于系统发展验证阶段,相关技术组合正在为真正的市场推广进行产品稳定性提升,且大部分备选技术组合充分利用了植物和湿地等生态技术的优势,既实现了较强的同步脱氮除磷,又具有运行和维护成本低的市场优势,符合减污降碳协同增效的政策背景,故更具有推广价值。备选LOT技术组合基本实现了成本优化和低碳低耗的技术运营模式,可满足污水的资源化及生态环境的优化需求。本研究结果可为低碳低耗污水处理技术的成熟度评估和筛选提供参考。     

南水北调中线水源地小流域面源污染生态阻控

丹江口水库作为南水北调中线工程的水源地,水质保护极其重要,以小流域为单元建设面源污染生态阻控系统是控制库区氮磷输入的重要途径。结合丹江口库区现状,提出“控山”“净水”“护林”“保田”“治村”五位一体的小流域面源生态阻控总体思路,将汇水流域、汇水沟道、塘洼节点等区域的措施耦合衔接,功能上互补,形成生态阻控系统。小流域面源生态阻控技术的实施包括本底调查和问题识别、措施布局设计、工程建设和运行监测等步骤。该技术方法在丹江口库周的钱家沟小流域开展了应用实践,阻控系统建设完毕后的监测结果显示,小流域TN平均下降33.9%,TP平均下降49.1%,总体阻控效果较好,可为南水北调中线水源地小流域的面源治理提供参考。     

The Evolution of the Environmental Quality Concept: From the US EPA Red Book to the European Water Framework Directive

- DOI: http://dx.doi.org/10.1065/espr2006.01.003 Background Water Quality Criteria were firstly defined in the 1970s by the EPA in the USA and the EIFAC in Europe, recognizing the need for protecting water quality in order to allow the use of water resources by man. In the 1990s, the European Commission emphasized the importance of safeguarding structure and function of biologic communities. These approaches were chemically-based. The European Water Framework Directive (WFD) substantially changes the concept of Water Quality, by assuming that a water body needs to be protected as an environmental good and not as a resource to be exploited. In this frame, the biological-ecological quality assumes a prevailing role. Main Features The Water Quality concept introduced by the WFD is a challenge for environmental sciences. Reference conditions should be defined for different typologies of water bodies and for different European ecoregions. Suitable indicators should be developed in order to quantify ecological status and to define what a 'good' ecological status is. Procedures should be developed for correlating the deviation from a good ecological to the effects of multiple stressors on function and structure of the ecosystem. The protection of biodiversity becomes a key objective. In this frame, the traditional procedures for ecotoxicological risk assessment, mainly based on laboratory testing, should be overcome by more site-specific approaches, taking into account the characteristics and the homeostatic capabilities of natural communities. In the paper an overview of the present knowledge and of the new trends in ecotoxicology to get these objectives will be given. A procedure is suggested based on the concept of Species Sensitivity Distribution (SSD). Recommendations and Perspective . The need for more site-specific and ecologically-oriented approaches in ecotoxicology is strongly recommended. The development of new tools for implementing the concept of 'Stress Ecology' has been recently proposed by van Straalen (2003). In the same time, more 'cological realism'is needed in practically applicable procedures for regulatory purposes.     

Quantitation of Hydroxyl Radicals from Photolysis of Fe(III)-Citrate Complexes in Aerobic Water (5 pp)

Background For their high photoreactivity, Fe(III)-carboxylate complexes are important sources of H2O2 for some atmospheric and surface waters. Citrate is one kind of carboxylate, which can form complexes with Fe(III). In our previous study, we have applied Fe(III)-citrate complexes to degrade and decolorize dyes in aqueous solutions both under UV light and sunlight. Results have shown that carboxylic acids can promote the photodegradation efficiency. It is indicated that the photolysis of Fe(III)-citrate complexes may cause the formation of some reactive species (e. g. H2O2 and ·OH). This work is attempted to quantify hydroxyl radicals generated in the aqueous solution containing Fe(III)-citrate complexes and to interpret the photoreactivity of Fe(III)-citrate complexes for degrading organic compounds. Methods By using benzene as the scavenger to produce phenol, the photogeneration of ·OH in the aqueous solution containing Fe (III)-citrate complexes was determined by HPLC. Results and Discussion In the aqueous solution containing 60.0/30.0 mM Fe(III)/citrate and 7.0 mM benzene at pH 3.0, 96.66 mM ·OH was produced after irradiation by a 250W metal halide light (l ≥ 313 nm) for 160 minutes. Effects of initial pH value and concentrations of Fe(III) and citrate on ·OH radical generation were all examined. The results show that the greatest photoproduction of ·OH in the aqueous solution (pH ranged from 3.0 to 7.0) was at pH 3.0. The photoproduction of ·OH increased with increasing Fe(III) or citrate concentrations. Conclusion In the aqueous solutions containing Fe(III)-citrate complexes, ·OH radicals were produced after irradiation by a 250W metal halide light. It can be concluded that Fe(III)-citrate complexes are important sources of ·OH radicals for some atmospheric and surface waters. Recommendations and Outlook It is believed that the photolysis of Fe(III)-citrate complexes in the presence of oxygen play an important role in producing ·OH both in atmospheric waters and surface water where high concentrations of ferric ions and citrate ions exist. The photoproduction of ·OH has a high oxidizing potential for the degradation of a wide variety of natural and anthropogenic organic and inorganic substances. We can use this method for toxic organic pollutants such as organic dyes and pesticides.     

Bacterial community structure analyses to assess pollution of water and sediments in the Lake Shkodra/Skadar, Balkan Peninsula

- Goal, Scope, Background. Lake Skadar is the largest lake in Balkan Peninsula, located on the Montenegro-Albanian border. The unique features of the lake and wide range of endemic and rare or endangered plant and animal species resulted in the classification of the Skadar as a wetland site of international significance. In spite of its importance the Lake is influenced by inflowing waters from river Morača and other regional rivers contaminated by the industry, municipal and agricultural activities in the area. Therefore, the Lake has been subject of various physical, chemical, biological and toxicological examinations. However, community-level analyses are most relevant to assess the effect of stressors on aquatic ecosystems. In the present study bacterial community structure among differently polluted sites of the lake was compared by genetic fingerprinting technique. Methods Water and sediment samples were collected from five differently polluted sampling sites on the Lake Skadar in spring and autumn of the same year. The bacterial community structure in the samples was characterized and compared by temporal temperature gel electrophoresis (TTGE) analysis of polymerase chain reaction-amplified bacterial 16S rRNA genes. Results and Discussion The TTGE analysis resulted in many distinguishable and reproducible band patterns, allowing reliable comparison of bacterial communities among sampling sites. Results on the bacterial community structure revealed that three of the selected locations can be considered as sites that have not shown any pollution degradation determined by our method, due to similar structure of bacterial community in the sediment samples. On the other hand, significant shifts in bacterial community structure in the mouth of the river Morača and Plavnica were shown. Since the results coincide with some of the bioassays and chemical analysis performed previously, the changes in bacterial community structure are explained as an effect of antropogenic pollution on the lake ecosystem by waters of river Morača and stream Plavnica. Conclusion The TTGE has proven to be an efficient and reliable method to monitor bacterial dynamics and community shifts in aquatic environment, especially in the sediments. Within the variety of environmental quality assessments the use of TTGE analyses of bacterial community is strongly recommended, particularly as an initial investigation. However, in any conclusion on the state of the environment, the TTGE results should be combined to some other biological, chemical and hydrological data. Recommendation and Outlook Since prokaryotes are a crucial group of organisms in the biosphere, the ecosystem function studies are largely based on bacterial communities. Therefore, bacterial community structure analysis should be a part of an integrated weight of evidence approach in pollution assessment. In case of Triad approach, consisting of chemical analyses, bioassays, and community studies in the field, the TTGE bacterial community structure analyses should be placed in the later Triad leg. In comparison to other community studies, based on various biotic indices, the TTGE bacterial community analysis has proven to be very sensitive, reliable and less time consuming.     

Temporal genetic variability and host sources of Escherichia coli associated with fecal pollution from domesticated animals in the shellfish culture environment of Xiangshan Bay, East China Sea

This study was conducted to analyze the genetic variability of Escherichia coli from domesticated animal wastes for microbial source tracking (MST) application in fecal contaminated shellfish growing waters of Xiangshan Bay, East China Sea. (GTG)₅ primer was used to generate 1363 fingerprints from E. coli isolated from feces of known 9 domesticated animal sources around this shellfish culture area. Jackknife analysis of the complete (GTG)₅-PCR DNA fingerprint library indicated that isolates were assigned to the correct source groups with an 84.28% average rate of correct classification. Based on one-year source tracking data, the dominant sources of E. coli were swine, chickens, ducks and cows in this water area. Moreover, annual and spatial changes of E. coli concentrations and host sources may affect the level and distribution of zoonotic pathogen species in waters. Our findings will further contribute to preventing fecal pollution in aquatic environments and quality control of shellfish.