Impacts of n-alkane concentration on soil bacterial community structure and alkane monooxygenase genes abundance during bioremediation processes

Petroleum hydrocarbons, mainly consisting of n-alkanes and polycyclic aromatic hydrocarbons (PAHs), are considered as priority pollutants and biohazards in the environment, eventually affecting the ecosystem and human health. Though many previous studies have investigated the change of bacterial community and alkane degraders during the degradation of petroleum hydrocarbons, there is still lack of understanding on the impacts of soil alkane contamination level. In the present study, microcosms with different n-alkane contamination (1%, 3% and 5%) were set up and our results indicated a complete alkane degradation after 30 and 50 days in 1%- and 3%-alkane treatments, respectively. In all the treatments, alkanes with medium-chain length (C₁₁-C₁₄) were preferentially degraded by soil microbes, followed by C₂₇-alkane in 3% and 5% treatments. Alkane contamination level slightly altered soil bacterial community, and the main change was the presence and abundance of dominant alkane degraders. Thermogemmatisporaceae, Gemmataceae and Thermodesulfovibrionaceae were highly related to the degradation of C₁₄- and C₂₇-alkanes in 5% treatment, but linked to alkanes with medium-chain (C₁₁-C₁₈) in 1% treatment and C₂₁-alkane in 3% treatment, respectively. Additionally, we compared the abundance of three alkane-monooxygenase genes, e.g., alk_A, alk_P and alk_R. The abundance of alk_R gene was highest in soils, and alk_P gene was more correlated with alkane degradation efficiency, especially in 5% treatment. Our results suggested that alkane contamination level showed non-negligible effects on soil bacterial communities to some extents, and particularly shaped alkane degraders and degrading genes significantly. This study provides a better understanding on the response of alkane degraders and bacterial communities to soil alkane concentrations, which affects their biodegradation process.

Open image in new window

     

Pesticide residues in products of plant origin in the European Union

The results of a co-ordinated monitoring programme for pesticide residues in the European Union and Norway carried out in 1996 and 1997 are presented. The aim of this programme is to work towards a system, which makes it possible to estimate actual dietary pesticide intake for the population of the European Union. Based on a statistically dérived sampling plan and within the limited number of pesticides/commodities analysed, the most critical pesticides (benomyl group and dithiocarbamates) and commodities (mandarine and lettuce) were identified. In case of detected non-compliances, repeated sampling and, if necessary, enforcement actions are to be taken by national authorities. The programme will be continued in the next years.     

Mapping Land-Cover and Mangrove Structures with Remote Sensing Techniques: A Contribution to a Synoptic GIS in Support of Coastal Management in North Brazil

This article deals with the development and application of a cartographic database for a synoptic Geographic Information System (GIS). Its purpose is the storage and evaluation of the heterogeneous datasets of the interdisciplinary scientific research program MADAM (Mangrove Dynamics and Management), which aims to develop recommendations for a tailored integrated coastal management scheme for the mangrove ecosystem at Bragança (North Brazil). The article describes the integration of remote sensing data, aerial photographs, as well as point data provided by fieldwork from different scientific fields. Using various innovative processing techniques and different scale-resolution levels, an assessment of temporal–spatial changes of the mangrove peninsula and the adjacent rural socioeconomic impact area, the type of mangrove structure, as well as a land-use cover analyses was undertaken. The definition of the spatial level of detail was found to be a major issue in the development of the GIS, as well as during the processing and analysis procedures. A division between strong and weak patterns in the mangrove ecosystem could be made, which implies different management measures and sets of specific interdisciplinary studies and monitoring at hierarchical scales.     

再论在《授予博士、硕士学位和培养研究生的学科、专业目录》中设立“安全科学与工程”一级学科

从社会必要性、现实可行性、学科的实践基础、学科的科学基础、学科的结构体系等方面,对在《授予博士、硕士学位和培养研究生的学科、专业目录》中设立“安全科学与工程”一级学科进行了论述,提出了“安全科学与工程”下设二级学科、专业的框架;阐述了“安全科学与工程”和其他与安全学科相关学科的关系、生源关系、与现有安全学科相关的二级学科的关系、与现有安全学科相关的二级学科的学位授予关系以及与其他学科的学缘关系。论证结论表明目前设立“安全科学与工程”一级学科,条件已经成熟。建议国务院学位委员会尽快将“安全科学与工程”单列为一级学科,并在其下设“安全科学”、“安全工程”2个二级学科、专业。     

人群疏散中"非适应性"行为的研究

本文从人与人的相互作用和社会学、心理学的角度,对人群疏散中“非适应性”行为的理论、计算机模型、模拟原理等进行了较为深入的研究,并以具体实例说明了Building Exodus软件在人群疏散模拟分析中的具体应用,为完善该研究方向的计算机模型和促进软件的开发提供理论和方法的指导.文章得出的结论是：“非适应”人群行为的研究需要从心理学和社会学的角度建立人群中个人行为与社会行为的理论框架.“非适应”人群行为的研究方法必须与紧急情况相结合,而紧急情况是一个由多个人员组成的复杂系统,大量人群环境的模拟需要涉及到人与人之间,人与环境之间的相互作用.     

海平面上升的灾害效应及其研究现状

海平面上升是全球变暖和沿海地区人类活动加剧的必然结果,海平面上升加剧了沿海灾害,威胁着沿海地区社会经济的持续发展.文章分析了海平面上升引起的风暴潮加剧、海岸侵蚀、潮滩湿地减少、涵闸废弃、洪涝灾害加剧、海堤破坏、海水入侵等灾害效应及研究现状,提出当前海平面上升灾害效应研究中存在的问题及今后的研究重点.     

中国城市自然灾害区划编制

依据灾害系统理论和中国自然灾害数据库,构建了综合城市化水平(C1)指标和综合自然灾害强度(QC)指标;运用数字地图技术,在模型与图谱互馈过程中,实现了中国城市承灾体与致灾因子的综合定量评价,编制了中国城市自然灾害区划图.将中国区划为3个一级区,即沿海城市灾害区、东部城市灾害区和西部城市灾害区,以及15个二级区和22个三级区,为城市灾害风险管理和中国自然灾害救助区划提供了科学依据.     

CSBR污水处理技术

介绍了CSBR污水处理技术的工艺流程、原理及特点。     

基于GM(1,1)模型的安全管理目标值确定方法

在事故预防中,安全目标管理是非常重要的工作之一。在确定管理目标时,由于不可能全面、真实地掌握所有信息,同时决策的信息量小,没有确定的分布规律,因此借助灰色理论建立的年伤亡次数与时间之间数值模型,可以反映安全技术措施的持续改进,安全管理的加强,安全教育工作的贯彻以及人们对安全与日俱增的要求。实例表明,采用灰理论进行预测,有以下几个优点:优于传统的以概率论和模糊数学为基础的预测方法;预测结果精度高;可以从多角度考查对象,得出的数据更能体现企业安全状况的现实规律,反映企业现阶段的安全状况。同时为制定科学、合理而可行的安全管理目标提供依据,促使企业安全管理提高到一个新水平。     

安全产品的供求特性及其与行业安全形势的关系初探

基于安全经济学的基本原理，通过对不同行业的自动安全水平和法定安全水平之间的关系的分析，论述了不同行业安全产品的需求特性，以及与此相适应的安全产品供给特性；并对安全产品的特殊供求机制与特定行业的安全形势之间的关系进行了初步的探讨，提出了提高行业安全水平的对策。