不同曝气方式对人工湿地细菌多样性、代谢活性及功能的影响

细菌在人工湿地去除污染物过程中起着非常关键的作用.基于DNA和RNA高通量测序技术探讨了不同曝气强化方式影响下的人工湿地单元内细菌多样性、代谢活性和功能.结果发现:①养殖废水和人工湿地处理组共检测到细菌4 042个操作分类单元(OTUs),其中α-变形菌、γ-变形菌和拟杆菌为多样性最高的类群,且人工湿地曝气强化方式会在...     

近50年丝绸之路经济带中国境内冰川变化

冰川是丝绸之路经济带中国境内重要的水资源,对该区农业建设和经济发展至关重要。基于修订后的中国第一次冰川编目数据和最新发布的第二次冰川编目数据,对丝绸之路经济带中国境内冰川变化进行分析。结果表明：（1）丝绸之路经济带中国境内现有冰川22523条,面积25516.80 km²,冰储量约2592.85 km³,分别占我国冰川相应总量的46.37%、49.22%和57.39%,其中新疆维吾尔自治区冰川储量最为丰富,共计2366.25 km³。（2）丝绸之路经济带中国境内冰川以面积<0.5 km²的冰川数量最多,共计15519条,占冰川总数量的68.90%;面积则以介于1~5 km²冰川为主,共计6833.71 km²,占冰川总面积的26.78%;各山系的冰川退缩海拔高度不同,面积减少速度在各个高度带均有差异。（3）近50年间丝绸之路经济带中国境内冰川面积共减少4527.43 km²,变化百分比为-20.88%,有3114条冰川消失,冰川冰储量损失约419.35 km³。（4）丝绸之路经济带中国境内冰川变化整体呈现自西向东加快趋势,减少速率整体上有自西南向东北加快趋势;冰川朝北消失数量大于朝南消失数量,东北方向面积减少最多,东南方向面积减少最快。（5）近50年间丝绸之路经济带中国境内有暖湿化趋势,冬季气温升高速率大于夏季且降水增加幅度小于夏季的气候组合模式,不利于冰川的积累从而导致冰川退缩;冰川发育规模对冰川退缩也有一定影响,但各山系冰川变化驱动力具有空间差异。     

大连市夏季VOCs化学反应活性及来源

为了解大连市环境空气挥发性有机物（VOCs）污染特征及来源,基于2020年6~8月高时间分辨率VOCs在线观测数据,对大连市大气VOCs的浓度水平、组成特征、反应活性及来源情况进行了分析.结果表明φ（VOCs）的平均值为（10.21±5.71）×10^-9,其中烷烃占比为66.35%,烯烃为11.89%,炔烃为7.75%,芳香烃为14.01%.VOCs和NO_x呈现夜间高,白天低的特征,而O₃变化趋势相反.综合考虑物种活性,确定甲苯、乙烯、间/对-二甲苯、1-己烯、正丁烷、异戊烷、正戊烷和异戊二烯是影响大连市大气VOCs的关键物种,优先控制烯烃和芳香烃类化合物的排放是改善大连市夏季O₃污染的关键.PMF源解析结果显示交通源（26.38%）、燃烧源（22.75%）、工业排放源（17.09%）、溶剂使用源（14.59%）、天然源（11.72%）和其他（7.47%）为监测期间VOCs的主要来源,交通源和燃烧源排放是大连市夏季O₃防控的重点污染源.     

论知识经济下经济安全评估及策略

随着知识经济的来临,经济全球化趋势越来越明显,国家间的经济联系不断增强,同时也随之产生的国家间的经济竞争不断加剧,使得国家经济安全受到威胁。笔者针对当前的经济发展特征,就如何提高国家经济安全水平以增强国际竞争力探讨了影响国家经济安全的因素。从多方面的、综合性的影响经济安全因素中,找到影响经济安全的基本要素,据此从统计的可行性角度,科学地构建了评估经济安全的指标体系。所构建的指标体系对综合评价一个国家和地区的经济安全具有一定的合理性和科学性。最后,提出了有关保证经济安全的策略,以便当我国在知识经济来临之时,保证经济快速发展,能在经济全球化中不断提高自己的国际竞争力。     

Pencycuron application to soils: degradation and effect on microbiological parameters

Clay loam soil from agricultural fields of alluvial (AL) soil (typic udifluvent) and coastal saline (CS) soil (typic endoaquept) were investigated for the degradation and effect of pencycuron application at field rate (FR), 2-times FR (2FR) and 10-times FR (10FR) with and without decomposed cow manure (DCM) on soil microbial variables under laboratory conditions. Pencycuron degraded faster in CS soil and in soil amended with DCM. Pencycuron spiking at FR and 2FR resulted in a short-lived (in case of 10FR slightly longer) and transitory toxic effect on soil microbial biomass-C (MBC), ergosterol content and fluorescein diacetate hydrolyzing activity (FDHA). Amendment of DCM did not seem to have any counteractive effect of the toxicity of pencycuron on the microbial variables. The ecophysiological status of the soil microbial communities as expressed by microbial metabolic quotient (qCO2) and microbial respiration quotient (Q(R)) changed, but for a short period, indicating pencycuron induced disturbance. The duration of this disturbance was slightly longer at 10FR. Pencycuron was more toxic to the metabolically activated soil microbial populations, specifically the fungi. It is concluded that side effects of pencycuron at 10FR on the microbial variables studied were only short-lived and probably of little ecological significance.     

高效石油烃降解菌的筛选及其对原油污染土壤的修复

从陕北原油污染土壤中筛选出7株高效石油烃降解菌,其中黄杆菌属CC-2、不动细菌属SC-5、假单胞菌属SC-6表现出较强的石油烃降解能力。通过单因素试验和正交试验考察总石油烃(TPH)降解效果的影响因素,得出各因素对TPH降解率影响程度的大小次序为:溶液p H降解温度降解菌接种量摇床转速,且在降解菌接种量为7%(φ)、溶液p H为7、降解温度为30℃、摇床转速为150 r/min的最适处理条件下,菌株SC-6的TPH降解率可达61.23%。原油污染土壤生物修复实验结果表明:高效石油烃降解菌的投加有利于土壤TPH降解率和酶活性的提高;"菌株SC-6+营养剂"组修复处理42 d后的TPH降解率可达57.59%。     

How and why is Aquatic Quality Changing at Nahanni National Park Reserve, nwt, Canada?

Nahanni National Park Reserve is located at southwestern NWT-Yukon border. One of the first UNESCO World Heritage sites, Nahanni lies within Taiga Cordillera and Taiga Shield Ecozones. Base and precious metal mining occurred upstream of Nahanni prior to park establishment. Nahanni waters, sediments, fish, and caribou have naturally elevated metals levels. Baseline water, sediment and fish tissue quality data were collected and analyzed throughout Nahanni during 1988–91 and 1992–97. These two programs characterized how aquatic quality variables are naturally varying in space and time, affected by geology, stream flow, seasonality, and extreme meteorological and geological events. Possible anthropogenic causes of aquatic quality change were examined. Measured values were compared to existing Guidelines and site-specific objectives were established.     

基于全过程治理的环境规制减排机制研究——来自长江经济带数据的实证检验

基于2007~2017年长江经济带11个省市的面板数据,利用中介效应模型探究全过程治理视域下政府主导型和市场激励型2类环境规制的减排机制.研究发现,政府主导型环境规制和市场激励型环境规制对SO₂排放均具有显著的抑制作用,其影响系数分别为-0.154和-0.209.其中政府主导型环境规制在源头防控、过程控制和末端治理的全过程都起到显著的减排效应,而市场激励型环境规制只通过末端治理实现减排.因此,尽管市场激励型环境规制具有低成本、高效率的优点,但考虑到源头防控和过程控制在生态环境保护中发挥的根本性作用,对于经济结构和经济发展方式较为落后的地区和行业,仍要重视以政府为主导的环境规制,通过因地制宜、合理科学地运用环境规制工具以实现高效的全过程污染治理.     

The Potential of Using Solar Energy to Process Full-Fat Soybeans (Glycine max) to Reduce Urease Activity

The objective of this study was to investigate the efficacy of panel solar cookers in reducing urease activity in full-fat soybeans (Glycine max). Changes in urease activity of soaked (SM), coarse-milled (CM) and whole dry (WM) full fat soybeans were investigated by roasting for 0, 30, 60, 90, 120, 150 and 180 min in multiple reflector panel solar cookers, in a 3 3 3 factorial experiment. Soaking soybeans for 14 h reduced (p<0.05) ^{1 1}P < 0.05 means that the probability (p) of falsely concluding significant difference between values obtained after statistical analysis was less than 5% (0.05). urease activity by 9%, from 6.58 meqNH₃/g DM to 5.98 meqNH₃/g DM. After 180 min of solar roasting, urease activity levels had declined by 81%, 67% and 23% in soaked, milled and whole dry soybeans respectively. Full fat soybean urease activity can be reduced faster in soaked than in dry soybeans. Findings suggest that there is potential in using multiple reflector panel solar cookers to reduce urease activity in full fat soybeans.     

纳米零价铁在应用中存在的问题及提高反应活性的方法

纳米零价铁对多种污染物质均有较好的去除效果,在污染的水体、土壤及底泥中被广泛研究与应用。前人对纳米零价铁的制备、在污染治理各方面的应用、作用的机理等方面进行了较为详细的总结,针对纳米零价铁在应用中存在的问题虽有提及,但少有人集中进行整理。本文主要针对纳米零价铁在环境治理方面存在的问题进行论述并对提高其反应活性的常用方法进行了总结,以期为纳米零价铁实际应用领域的深入研究提供借鉴并拓展新的思路。