Implications of denitrification in the ecological status of an urban river using enzymatic activities in sediments as an indicator

A better understanding of the effects of a number of environmental factors on denitrification is vital for analyzing its role as nitrogen sink and providing deeper knowledge about the ecological status of a nitrate-rich ecosystem. Since few studies have addressed the occurrence and implications of denitrification in river sediments, and complexity of interactions among all these environmental factors makes comprehension of the process difficult, the potential of sediments from the Deba River to attenuate nitrate excess through denitrification was investigated. For this purpose, we adapted an in vitro method to measure activities of two enzymes contributing to the entire multiple-step nitrate reduction: Nitrate Reductase and Nitrite Reductase. The environmental features that influence both or single enzymatic activities were identified as oxygen availability, regulated directly by the moisture content or indirectly through the aerobic respiration, organic matter and nitrate content of sediments, and electrical conductivity and exchangeable sodium percentage of water. Additionally, our results showed that Nitrate Reductase catalyzes the principal limiting step of denitrification in sediments. Therefore, taking this enzymatic activity as an indicator, the southern part of the Deba River catchment presented low potential to denitrify but nitrate-limited sediments, whereas the middle and northern parts were characterized by high denitrification potential but nitrate-rich sediments. In general, this study on denitrifying enzymatic activities in sediments evaluates the suitability of the management of the effluents from wastewater treatment plants and municipal sewages to ensure a good ecological status of the Deba River.     

苏北灌河口多介质多环芳烃污染调查及生态风险分析

于2018年1,7和11月对苏北灌河口典型介质中多环芳烃(PAHs)的污染现状进行了调查。采用气相色谱-质谱联用仪(GC-MS)对水样、沉积物、植株和生物样品中16种PAHs富集组成特征及生态风险进行分析。结果表明,水相,悬浮颗粒物和沉积物中PAHs平均值均为枯季(1 998 ng/L, 2 987 ng/g, 1 056 ng/g)高于洪季(1 698 ng/L, 630 ng/g, 558 ng/g);不同季节水相、悬浮颗粒物和沉积物中均以2+3环PAHs为主;水相中苯并[a]蒽(BaA)、[艹屈](CHR)、苯并[b+k]荧蒽(B[b+k]FA)质量浓度高于美国环保署(US EPA)推荐的水质量标准,悬浮颗粒物和沉积物中芴(FL)和菲(PHE)对水生生物可能存在不利影响;互花米草和芦苇的落叶效应使得沉积物中PAHs质量分数高于光滩;芦苇根系沉积物和互花米草根系沉积物中PAHs的组成差异较大;成熟期(11月)蟹体内PAHs平均质量分数远高于生长期(7月),蟹体内更易富集低环数(2+3环)PAHs。     

武汉市东湖抗生素污染现状及生态风险评估

对东湖水域内16个点位进行采样,采用超高效液相色谱-三重四极杆质谱联用仪对28种抗生素做了污染现状调查及生态风险评估。研究发现,有20种抗生素在不同点位被检出,检出浓度由高到低为：喹诺酮类、氯霉素类和磺胺类,污染物检出情况总体呈现“南高北低,东高西低”的结果。考虑到东湖南部采样点位周边有多个农业种植、水产养殖和畜禽养殖地及其对东湖的潜在抗生素污染,证实了人类活动与抗生素污染密切相关。对抗生素采用风险商法做生态风险评估,结果表明,东湖南部采样点位的恶喹酸和氟甲喹的生态环境风险处于较低水平,其他抗生素的生态风险可以忽略。     

崇明生态岛建设解析

崇明岛是位于长江口、世界上面积最大的河口冲积岛。笔者构建了科学性与可操作性、现实性与前瞻性、针对性与示范性相结合的生态岛建设指标体系,并在崇明世界级生态岛建设中发挥了“引领生态岛建设方向,规范建设行为,调控建设进程”的作用,崇明生态岛建设成效初显。为了进一步发挥崇明生态岛建设的示范作用,笔者还提出了建设生态文明特区等建议。     

广州后航道水环境污染的变化特征和对策

从珠江广州河段后航道多年的水质变化状况与广州市部分区域污染源情况看水体环境污染的变化特征，并提出了治理对策的建议。     

长荡湖生态环境现状及防治对策

长荡湖是太湖流域的重要湖泊之一，分析了引起该湖生态环境恶化的主要原因，提出控制污染源，减少污染物进入湖体的关键措施，采取压缩网网养殖规模，推广轮牧式养殖工艺，实施全年封草并培植沉水植物，防止长荡湖由草型湖泊向藻型湖泊的转变，逐步恢复长荡湖的生态环境。     

人口资源生态环境与可持续发展初探

主要介绍了人口、资源、生态环境与可持续发展所面临的问题，可持续发展的必要性。分析了污染原因、污染物对人、社会的危害。提出污染物防治及环境管理对策。     

Classification of coastal waters according to the new Italian water legislation and comparison with the European Water Directive

New legislation for the protection of inland surface waters, transitional waters, coastal waters and ground waters has recently been established in Italy. This law presents a new integrated approach, where all water bodies are considered as complex ecosystems to be studied in each of their components. The new concept of environmental quality of the water body, based on the ecological and chemical status, is also introduced. At the same time (i.e. the end of 2000), the European Community approved the European Water Framework Directive based on the same basic environmental concepts and criteria of the new Italian law. This paper analyses the important points and innovations required by the new Italian legislation for monitoring and classification of marine coastal waters. Details of definitions, parameters, analysis and monitoring programs are discussed. A comparison with the European Water Framework Directive is eventually given, underlining the specific characteristics of the Mediterranean sea, which have to be taken into consideration when applying the European Directive to this particular ecoregion.     

A targeting approach for ecosystem protection

The Critical Ecosystems Team of the US Environmental Protection Agency (EPA), Region 5, has developed an approach to prioritize and target ecologically high-quality areas for enhanced environmental protection in the Midwestern states of Illinois, Indiana, Ohio, Michigan, Minnesota and Wisconsin. Using this approach, we intend to employ a pro-active strategy to protect the environment by protecting and restoring natural ecosystems rather than the traditional EPA approach of remediating and attempting to restore already degraded habitats. The approach consists of two components: (1) partnership and (2) criteria. For the partnership component, we collected, mapped, and summarized information on ecosystems considered critical to federal and state agencies, tribes and non-profit organizations. Multi-county areas with high numbers of ecosystems identified by a variety of partners were designated as ‘Ecologically Rich Regions’. These Ecologically Rich Regions highlight broad geographic areas where there are high levels of partner interest and, correspondingly, areas with high potential for forming collaborative partnerships for enhanced environmental protection. The second component, which relies on criteria, is still under development and defines critical ecosystems as having three important properties: (1) high ecological diversity, (2) potential for long-term sustainability and (3) presence of relict native ecosystems or communities. The information compiled under both components of this ecosystem targeting approach will inform ecological risk managers and assessors about important ecosystems that should be considered in risk management and assessment processes.     

港口生态工程管理系统及评价方法研究

提出了建立港口生态工程管理的模式及指标体系，探讨了港口生态工程评价方法。