南宁市多环境介质中多环芳烃分布特征

为了确定多环境介质中多环芳烃的浓度、组成和分布特征,采集南宁市冬夏季空气、大气干湿沉降物、土壤和地下水样品,利用16种多环芳烃的成分谱,结合其物理化学性质,分析多环芳烃在多环境介质中的浓度、组成和分布特征,结果表明:1空气和大气干湿沉降物中PAHs均以2~3环为主,由于冬夏季节差异性,冬季ΣPAHs浓度高于夏季;2土壤中PAHs以2~3环为主,且土壤颗粒粒径分布差异性是导致不同层位PAHs分布特征差异的主要原因;3地下水中PAHs检出种类少,检出量小,也表明土壤包气带能够"截留"较多的PAHs;416种PAHs在不同环境介质中质量分数均呈现由低环向高环递减的趋势,且两地区冬夏季2~3环和5~6环PAHs在各环境介质中分布特征具有较好的一致性,但也有一定的差异.这与PAHs的理化性质、水文地质条件、城市污染状况、天气状况等方面有关.     

不同填料甲苯生物滤塔中微生物群落结构与代谢功能解析

对填料为珍珠岩、玻璃珠和聚苯乙烯泡沫(EPS)的甲苯生物滤塔中微生物群落的结构和代谢功能进行了分析.结果表明,在稳定运行阶段,生物滤塔的微生物群落结构相似且与接种物存在较大差异.3种填料的生物滤塔中在门水平上的优势菌均为变形菌门Proteobacteria(36.1%~67.5%)、放线菌门Actinobacteria(4.3%~43.4%)、厚壁菌门Firmicutes(3.0%~16.4%)和拟杆菌门Bacteroidetes(1.9%~10.2%);属水平上,相同的优势属为红球菌属Rhodococcus(2.4%~38.5%)和假单胞菌属Pseudomonas(5.9%~25.3%),在珍珠岩生物滤塔中相对丰度更高的属为戴沃斯氏菌属Devosia、戈登氏菌属Gordonia和根瘤菌科某属Rhizobiales_E,在玻璃珠和EPS生物滤塔中相对丰度更高的属为着色菌科某属Chromatiaceae_A和Fluviicola.不同填料的生物滤塔中微生物群落整体碳源代谢能力相似且相比接种物均显著下降,微生物群落结构与代谢呈现一致性,多样性水平均为珍珠岩EPS玻璃珠.与接种物相比,不同填料的生物滤塔中微生物结构物种多样性都降低,代谢多样性都升高.     

媒体报道、政府监管与企业环境信息披露

在中国经济和媒体环境发生巨大变革的情况下,外部压力对上市公司环境信息披露的影响研究面临新的社会背景。基于传播学议程设置理论、关注理论与信号传递理论,本文以2016年沪深A股八大重污染行业的315家上市公司为研究对象,研究了媒体报道与政府监管对上市公司环境信息披露水平的影响。其中,媒体类型既考虑了传统纸媒,也考虑了以新浪微博为代表的网络新媒体,政府监管方面采用2014年调整后的PITI指数对监管力度进行评价。研究发现,媒体报道数量越大,上市公司环境信息披露的内容越丰富,但并不能提高其信息披露质量;上市公司环境信息披露质量主要受媒体报道倾向性的影响,而媒体报道的数量对其影响较弱;地方政府对企业环境信息公开的监管力度对企业环境信息披露的影响并不显著。此外,随着地方政府监管力度的加大,媒体对企业的关注度下降,导致政府监管在媒体监督企业环境信息过程中具有一定的削弱作用。研究表明,随着近年来生态环境保护法制化进程的大力推进,环境制度约束相对舆论监督,在企业信息披露过程中发挥着越来越重要的作用。     

Transport of a non-volatile contaminant in unsaturated porous media in the presence of colloids

Stable colloidal particles can travel long distances in subsurface environments and carry particle-reactive contaminants with them to locations further than predicted by the conventional advective-dispersive transport equation. When such carriers exist in a saturated porous medium, the system can be idealized as consisting of three phases: an aqueous phase, a carrier phase, and a stationary solid matrix phase. However, when colloids are present in an unsaturated porous medium, the system representation should include one more phase, i.e. the air phase. In the work reported, a mathematical model was developed to describe the transport and fate of the colloidal particles and a non-volatile contaminant in unsaturated porous media. The model is based on mass balance equations in a four-phase porous medium. Colloid mass transfer mechanisms among aqueous, solid matrix, and air phases, and contaminant mass transfer between aqueous and colloid phases are represented by kinetic expressions. Governing equations are non-dimensionalized and solved to investigate colloid and contaminant transport in an unsaturated porous medium. A sensitivity analysis of the transport model was utilized to assess the effects of several parameters on model behavior. The colloid transport model matches successfully with experimental data of Wan and Wilson. The presence of air-water interface retards the colloid transport significantly counterbalancing the facilitating effect of colloids. However, the retardation of contaminant transport by colloids is highly dependent on the properties of the contaminant and the colloidal surface.     

非正规垃圾填埋场包气带介质的污染物阻滞能力研究

非正规垃圾填埋场已成为地下水的潜在污染源,给城市供水安全带来了极大风险。以北京某非正规垃圾填埋场的3种典型包气带介质为研究对象,以Br-为示踪剂,采取土柱实验和数值模拟相结合的方法,通过对场区3种典型包气带介质饱和与非饱和状态下的Br-迁移速率的比较,探讨包气带介质对污染物的阻滞能力。结果表明,Br-在不同包气带介质饱和状态下的迁移速率为中砂>细砂>砂质粉土,这可能与不同介质中粉粒和粘粒的含量有关,同时介质的有机质含量也会影响Br-的迁移速率,但前者因素占了主导作用;在Br-迁移过程中,不同包气带介质的含水量是影响其迁移速率的主要因素,若能合理控制场区的地下水位,使得包气带介质长期处于非饱和状态,将会大大延缓垃圾渗滤液中污染物向地下水迁移;针对特定的非正规垃圾填埋场,可采取抽水等措施,控制场区的细砂和砂质粉土层处于非饱和状态,充分利用包气带介质在非饱和状态时较强的污染物阻滞能力,阻隔或延缓垃圾渗滤液中的污染物进入地下水中。     

生物膜氧化沟污水处理性能的研究

生物膜氧化沟是在普通氧化沟内放置合适填料，使之成为活性污泥法与生物膜法相结合的混合污水处理工艺。本研究通过清水试验，选择出了生物膜氧人诉合适填料及其安装方式，并同时比较了生物膜氧化沟和普通氧化沟的传质效果，水流阻力、水力混合特性。通过污水试验，确定了生物膜氧化沟的填料最佳填充率。并比较了生物膜氧化沟和普通氧化沟的去除ＣＯＤ、ＳＳ、ＴＮ效率及两者的污泥性能。     

Identifying conservation priorities for threatened Eastern Himalayan mammals

To augment mammal conservation in the Eastern Himalayan region, we assessed the resident 255 terrestrial mammal species and identified the 50 most threatened species based on conservation status, endemism, range size, and evolutionary distinctiveness. By using the spatial analysis package letsR and the complementarity core‐area method in the conservation planning software Zonation, we assessed the current efficacy of their protection and identified priority conservation areas by comparing protected areas (PAs), land cover, and global ecoregion 2017 maps at a 100 × 100 m spatial scale. The 50 species that were most threatened, geographically restricted, and evolutionarily distinct faced a greater extinction risk than globally nonthreatened and wide‐ranging species and species with several close relatives. Small, medium‐sized, and data‐deficient species faced extinction from inadequate protection in PAs relative to wide‐ranging charismatic species. There was a mismatch between current PA distribution and priority areas for conservation of the 50 most endangered species. To protect these species, the skewed regional PA distribution would require expansion. Where possible, new PAs and transboundary reserves in the 35 priority areas we identified should be established. There are adequate remaining natural areas in which to expand current Eastern Himalayan PAs. Consolidation and expansion of PAs in the EH requires strengthening national and regional transboundary collaboration, formulating comprehensive regional land‐use plans, diversifying conservation funding, and enhancing information sharing through a consolidated regional database.     

Knowledge-based Journalism in Science and Environmental Reporting: Opportunities and Obstacles

Recent calls for knowledge-based journalism advocate a new level of formal knowledge in news reporting to meet the professional challenges caused by rapid change in the news industry. Scientifically knowledgeable journalism has the potential to redefine the existing science–media relationship. However, the audience for such journalism is unclear, nor is it known how this new journalism would function within rapidly changing newsroom practices. Implementing knowledge-based journalism requires theory-based propositions to show the actual benefits of improved scientific understanding for news consumers and an understanding, from research into professional cultures, of why new practices in journalism are adopted or abandoned. This paper develops that theoretical basis by examining knowledge-based journalism’s potential and some of the intellectual and institutional barriers to it.     

Government to Citizens (G2C) communication and use of social media in the post-disaster reconstruction phase

Post-disaster reconstruction (PDR) poses specific and complex challenges that government agencies have to deal with. Existing crisis management and communication models as well as literature on social media adoption by public organisations tend to focus on the critical stage, neglecting the issues that arise when the social, physical and cultural environments affected by a disaster have to be rebuilt. Conversely, this paper presents some preliminary findings on the Government to Citizen (G2C) communications and social media usage in PDR settings. The PDR process that followed the earthquakes in Emilia-Romagna (Northern Italy) in 2012 was used as a case study. Data derived from field notes and multiple-choice questionnaires revealed that government agencies provided information mainly about housing and infrastructure and financing and that they addressed this information to all citizens, although information was sometimes targeted specifically to business people, homeowners and members of community-based groups. Government officers gave preference to face-to-face contacts, Web portals and printed material. Social media were used predominantly as additional means of communication of PDR-related information, thus underrating their potential for community engagement and G2C bidirectional communication. In the discussions, findings are integrated into and validated against literature and communication theories.     

Biodegradation during contaminant transport in porous media: 1. mathematical analysis of controlling factors

Interest in coupled biodegradation and transport of organic contaminants has expanded greatly in the past several years. In a system in which biodegradation is coupled with solute transport, the magnitude and rate of biodegradation is influenced not only by properties of the microbial population and the substrate, but also by hydrodynamic properties (e.g., residence time, dispersivity). By nondimensionalizing the coupled-process equations for transport and nonlinear biodegradation, we show that transport behavior is controlled by three characteristic parameters: the effective maximum specific growth rate, the relative half-saturation constant, and the relative substrate-utilization coefficient. The impact on biodegradation and transport of these parameters, which constitute various combinations of factors reflecting the influences of biotic and hydraulic properties of the system, are examined numerically. A type-curve diagram based on the three characteristic parameters is constructed to illustrate the conditions under which steady and non-steady transport is observed, and the conditions for which the linear, first-order approximation is valid for representing biodegradation. The influence of constraints to microbial growth and substrate utilization on contaminant transport is also briefly discussed. Additionally, the impact of biodegradation, with and without biomass growth, on spatial solute distribution and moments is examined.