钚在某处置工程屏障水环境中化学形态及影响因素

针对某放射性废物包装容器回填处置工程屏障结构特征,采用岩体裂隙水浸泡工程屏障样品的方式,在对各平衡水样化学成分分析的基础上,利用地球化学模拟软件EQ3/6对钚在回填工程屏障水环境中的存在化学形态进行了模拟计算,得出钚在回填工程屏障水环境中主要以Pu(Ⅳ)价态Pu(OH)5-形式存在,同时水环境中pH值和Eh值的变化皆会影响钚的存在化学形态和价态。     

输入数据精度与准确性对SWAT模型模拟的影响

以潮河流域为研究区域,利用潮河流域1990~2013年监测数据,构建SWAT模型,在模型结构和参数不改变的情况下,探究输入数据精度（DEM分辨率）与准确性（降水插值）对径流和总氮模拟结果影响.结果显示：DEM分辨率变化（30~300m）对径流及总氮模拟效果不同,对径流模拟影响不明显,纳什系数（ENS）和R²可达到0.87以上;对总氮模拟结果影响较大,分辨率越精细,模拟效果越好.不同水文年,DEM分辨率变化对总氮负荷模拟表现不同.丰水年对总氮负荷影响较大,负荷量差异较为明显,枯水年影响相对较小;不同DEM分辨率下,年均（1993~2002年）总氮负荷强度空间分布相似,高负荷区均位于潮河中游,潮河上游及下游的负荷强度相对较低.不同降水输入数据站点分布、站网密度和准确性不同,流域内降水空间分布差异显著.总体上,基于站点较少的气象站插值数据与雨量站实测降水数据,径流和总氮模拟效果较为接近;基于SWAT官方雨量站插值数据,径流和总氮模拟效果较差.不同降水数据输入情景下,模拟的总氮负荷强度模拟的空间分布差异明显;降水量分布较高的区域,负荷量也较高;不同水文年下,不同降水输入对总氮负荷模拟表现不同.丰水年和枯水年,基于气象站插值数据的总氮模拟结果与基于雨量站实测数据的模拟结果较为接近,而基于SWAT官方雨量站插值的模拟误差较大;平水年,基于SWAT官方雨量站插值的模拟结果较气象站插值数据的模拟结果更好.该研究可为流域开展模型构建提供科学参考和借鉴.     

Potential dissemination mechanism of the tetC gene in Aeromonas media from the aerobic biofilm reactor under oxytetracycline stresses

The tetC gene has been found to be one of the most widely distributed tetracycline resistance (tet) genes in various environmental niches, but the detailed dissemination mechanisms are still largely unknown. In the present study, 11 tetC-containing Aeromonas media strains were isolated from an aerobic biofilm reactor under oxytetracycline stresses, and the genome of one strain was sequenced using the PacBio RSII sequencing approach to reveal the genetic environment of tetC. The tetC gene was carried by an IS26 composite transposon, named Tn6434. The tetC-carrying Tn6434 structure was detected in all of the A. media strains either in a novel plasmid pAeme2 (n=9) or other DNA molecules (n=2) by PCR screening. The NCBI database searching result shows that this structure was also present in the plasmids or chromosomes of other 13 genera, indicating the transferability of Tn6434. Inverse PCR and sequencing confirmed that Tn6434 can form a circular intermediate and is able to incorporate into a preexisting IS26 element, suggesting that Tn6434 might be responsible for the dissemination of tetC between different DNA molecules. This study will be helpful in uncovering the spread mechanism of tet genes in water environments.     

面向国土空间安全的工业园区风险监测评估系统设计思路

随着城市化的推进,城市的脆弱性不断加剧。近年来频发的生产安全事故,凸显了传统风险治理范式的局限性。源头防控、多元参与、数据驱动是当下生产安全风险治理的重要议题,而多元主体风险和系统性风险是治理的焦点。以整体性思维为指引,建构“三生”空间相互作用下的“双环模型”,为安全多维及时空多维视角下生产安全风险的治理提供理论基础和总体思路。挖掘信息技术对国土空间动态监测、风险认知积累和风险防控能力成长的积极作用,提出“扁平化”的风险监测评估框架体系并探讨信息平台的需求与架构。以风险交织的化工行业为例,重点关注工业园区主导下的生产安全风险多元防控范式和基础框架,为不同行业的多类型风险防控提供思路借鉴。     

非活化单过硫酸盐降解柳氮磺胺吡啶:动力学及机制

基于硫酸根自由基的活化单过硫酸盐(peroxymonosulfate, PMS)的高级氧化技术已被广泛应用于污染物去除过程,但有关利用PMS直接氧化去除有机污染物的研究尚不充分.本研究系统地考察了柳氮磺胺吡啶(sulfasalazine, SSZ)在PMS直接氧化过程中的降解动力学及降解途径.结果表明,SSZ的降解符合准一级反应动力学规律,增加PMS浓度或提高离子强度能够加快SSZ的降解速率;碱性条件有利于反应进行; Cl~-的存在显著促进了SSZ的降解;地表水会抑制SSZ的降解.通过质谱分析及活性位点鉴定,推测羟基化和SO_2基团挤脱反应是氧化的主要途径.本研究为基于非活化PMS去除水中磺胺类抗生素的应用可行性提供了依据.     

Eco-Compensation in Multi-District River Networks in North Jiangsu, China

Eco-compensation is a multi-disciplinary topic. There is no consensus on the issue of river eco-compensation across districts. Although policies regarding river eco-compensation have been issued in China since 2008, due to the high cost, eco-compensation has not been well implemented in the Taihu pilot region. Therefore, a simplified method based solely on water quality (both water quality and water volume included in the Taihu method) was proposed for North Jiangsu province (NJP). However, the formula was flawed and it led to payments being too low. Three problems need to be solved: (1) how to specify the eco-compensation areas; (2) how to test a reasonable eco-compensation model and (3) how to determine the compensation criterion. Solving these issues is already a priority. In this paper, three potential solutions surrounding eco-compensation are discussed: (1) three principles for selecting the representative eco-compensation areas are suggested; (2) the compensation calculation method based on contaminant flux above the ultra standard is revised and (3) a compensation criterion model based on the treatment costs of sewage is proposed. In the NJP case in 2009, the average eco-compensation criterion for chemical oxygen demand (COD) is 2,000 Chinese Yuan (CNY) per ton and ammonia nitrogen (NH₄–N) and total phosphorus (TP) are 8,000 CNY and 80,000 CNY per ton, respectively. Five districts needed to be compensated. The payments in the revised scheme were 4.15–586 million CNY, which were 16–48 times greater than that in the draft method. The new method can provide an important template for managers when drafting river eco-compensation schemes.     

干旱区生态环境对PRED系统影响的定量研究--以新疆和田民丰县为例

从可持续度模型的特点出发，分析影响干旱区可持续发展的重要因子，对原先较适用于工业发达，环境污染严重的大中小型城市的区域PRED系统模式进行了改进。针对西部干旱区特殊的地理环境和经济结构，将水资源总量和生态环境因子引入可持续度模型。结合干旱区的实际情况和已有模型，选用人口增长、经济发展、发展阶段、水资源总量和生态环境这五大因子建立新的模型。将其应用于新疆和田民丰县，根据其波动规律将民丰县可持续发展变化分为五个阶段。     

染料敏化太阳能电池纳米TiO2制备及多孔电极膜研究进展

本文就目前在染料敏化太阳能电池产业化中急需解决的TiO2纳晶制备、电极薄膜修饰与改进等热点问题的最新研究进展进行了综合评述,分析了存在的问题并提出了对策.     

“双向探索法”──一种研究移民环境容量的新方法

水利工程的移民环境容量受社会、经济、环境等诸要素的制约。本文以中国四川省开县为例,提出“双向探索法”,并应用于移民环境容量研究,研究方法可行、灵活,且求解迅速可靠,能为决策者提供多种行动方案和决策信息。为本领域的科学研究做了一次有意义的尝试。     

大连湾海域水质主要污染因子及污染源贡献分析

主要基于因子分析法构建因子诊断模型,对大连湾主要污染因子及空间分布特征进行研究,并根据海湾监测站位主要污染因子的优势比值以及不同类型污染源的排污特征分析,诊断目标区域内主要污染来源及不同类型污染源对邻近海域的贡献率。因子诊断结果表明,大连湾主要污染方式有5类,其中工业污水、生活污水和机械加工废水是主要的污染来源;污染源贡献率研究结果表明,臭水套海域各站点生活污水、加工制造和工业废水的贡献率最大值分别为24.7%、44.1%和40.1%。