沼液肥用效果及其潜在风险评述

沼液是沼气发酵过后的液体残留物,是一种优质的有机肥料,在农林业生产中具有极高的利用价值.简单介绍了沼液的成分,从沼液浸种、叶面施肥、抗病虫害3个方面阐述了沼液施肥对作物生长的影响,从土壤酸碱度、养分含量等方面总结了沼液灌溉对土壤性状产生的影响,从重金属、抗生素物质的积累以及促进温室气体排放方面简单归纳了沼液利用过程中可能对环境造成的潜在风险,并且对沼液进一步利用的前景进行了展望.     

Food Safety Considerations for CGIAR Research

ABSTRACT

In view of the CGIAR's identification of food safety as an area requiring priority attention to safeguard the economic interests of smallholder farmers and the poor, this paper aims to provide a general overview of the level of research and development attention accorded by the scientific and development community to this theme. This baseline survey of work undertaken exposes the nature of the problem; the food safety situation of the poor; food safety concerns in technology and policy research in the CGIAR; the role of capacity-building; and, subsequently, attempts to provide pointers to the CGIAR research community along which it could proceed. It is clear that within the CGIAR System, there has been no set strategy to provide guidance on the topic, and that work done to date has been largely of an ad hoc nature. The formulation of a strategic framework to guide the incorporation of food safety considerations in CGIAR research is now essential and would prevent duplication, capture synergies from the currently isolated activities and promote greater efficiency.     

农民工创业法律风险的表现、成因及防范对策研究

指出农民工创业可能存在如财政税收、合同、劳动用工等法律风险,分析了创业风险可能源于创业者自身法律风险意识不强等内因和政府保障不足等外因,最后提出了可通过建构提升农民工创业者及其员工法律风险意识、制定法律风险防范制度等内生性免疫系统,和行政机关、司法机关、职教机构、社会组织帮扶体外生性帮扶系统,以解决农民工创业中法律风险防范问题。     

基于AHP-ANN模型的土地整理工程投资风险评价——以江西省湖口县土地整理项目某标段为例

将层次分析法(AHP)和人工神经网络(ANN)相结合,采用层次分析法,对土地整理工程投资风险的各种因素进行深入研究,确定工程投资风险的评价指标体系,再利用人工神经网络投资分析评价建立投资风险评估AHP-ANN模型,并对此进行了可行性论证,为全面评估土地整理工程投资风险提供了新的思路和方法。     

淮南城区小学校园石楠叶面尘重金属污染特征及健康风险评价

叶面尘能够反映一定区域及时间内近地面大气颗粒物污染情况,可以模拟儿童在特定区域的灰尘暴露情况。以典型煤矿资源型城市淮南城区小学校园中石楠叶面尘及地表灰尘为研究对象,对比分析了其重金属含量、污染特征及来源的差异,并对叶面尘中重金属含量进行健康风险评价。结果表明:叶面尘重金属污染程度为ZnPbAsCuNiCoCr,其中Zn和Pb为中度污染,As和Cu为轻度-中度污染;地表灰尘中重金属污染程度为ZnPbCrCuNiCoAs,其中Zn为中度—强度污染,Pb为中度污染,Cr和Cu为轻度—中度污染。校园地表灰尘中重金属含量一般高于叶面尘。叶面尘主要来源于工业、交通排放、煤炭燃烧,还可能来自于二次扬尘和土壤母质。地表灰尘的来源主要为交通排放,其次是建筑物及公共设施磨损和土壤母质。手-口摄入是儿童灰尘重金属暴露的主要途径,重金属非致癌风险大小为PbAsCrCuZnCoNi,均不构成健康威胁,As、Co、Cr和Ni致癌风险均低于风险阈值,不存在致癌风险。     

基于改进Credit Metrics模型的商业银行信用风险度量及实证研究

信用风险是我国商业银行面临的主要风险。随着美国金融危机的蔓延,各国银行业已意识到加强信用风险监管的必要性。研究信用风险特征,建立合适的度量模型准确地度量我国商业银行的信用风险,是降低信用风险的必然要求,而Credit Metrics模型以其擅长度量非交易性资产的信用风险而著称。作者首先对Credit Metrics模型加以改进,使用我国的信用评级转移矩阵,其次考虑宏观经济和企业本身的非系统性风险,重新调整信用评级转移矩阵。最后以某家银行为基础,使用Credit Metrics模型进行实证研究,同时对于模型中的部分参数进行修正并对模型加以改进,从而完善Credit Metrics模型在我国商业银行业的应用。     

银行业集中度、银行规模与风险关系研究——基于中国16家商业银行面板数据的实证

基于中国上市的16家商业银行,以2005—2014年的面板数据为研究对象,运用面板门限回归进行实证分析。研究结果表明：银行业集中度与银行风险的线性关系不显著;在以资产规模作为门限变量时,银行风险与银行业集中度之间的确存在一种非线性关系,存在门限效应,资产规模的门限值约为603 019 220万元。当银行资产规模超过该门限值时,即对大型银行而言,银行业集中度与银行风险正相关关系不显著;当银行资产规模低于该门限值时,即对小型银行而言,银行业集中度与银行风险呈显著的正相关关系。     

Health Risks Assessment of Odor Gases from Sewage Treatment Plant

The compositions of odor gases in Jizhuangzi sewage treatment plant of Tianjin in the summer of 2011 and 2012 were monitored by GC-MS. Meanwhile 24 subjects (11 male, 13 female) were selected for acute exposure experiment by HOLTER. 67 kinds of odors were detected out, the concentration of odor gases emitted from grid was the highest, sulfide and oxygen-contained were major species of odor gases; the acute exposure experiment at the grid showed that blood pressure reacted normal, maximum heart rate was significantly higher than normal value, mostly in the field test period, while the HRV parameters all deviated from normal range, which indicated that malodorous gases induced the subjects' sympathetic nerve activity. According to health risks assessment of odor gases from sewage treatment plan, methylene chloride and benzene of malodorous gases in the sludge dewatering had potential risk, non-carcinogenic hazard index (HI) was less than 1, within an acceptable range.     

桂林市菜地土壤和蔬菜铜含量及其健康风险

在桂林地区蔬菜和菜地土壤铜含量进行大规模调查基础上,评价其污染程度,并用THQ评估经食用蔬菜摄入铜的健康风险。结果显示,桂林地区菜地土壤铜含量范围、中值、算术均值和几何均值分别为11.69～348.8mg·kg-1和27.41、34.62、29.43mg·kg-1,与桂林市土壤背景值相比,桂林市菜地土壤铜没有明显的积累;桂林地区蔬菜铜含量范围和平均值分别为0.032～3.530mg·kg-1和0.324mg·kg-1,与其他城市蔬菜铜含量相比,桂林地区蔬菜铜含量处于较低水平,通过蔬菜摄入铜的健康风险小。蔬菜对铜的富集能力以辣椒最高,因而其抗污染能力较差,白菜、包菜和萝卜对铜的富集能力最低。     

Heavy Metal Release from Some Industrial Wastes: Influence of Organic and Inorganic Acids, Clay Minerals, and Nanoparticles

Knowledge about heavy metal release from industrial solid wastes(ISWs) is crucial for better management of their environmental risks. This study was conducted to investigate the effect of organic and inorganic acids, clay minerals, and nanoparticles(NPs) on the release of heavy metals from sugar factory waste, ceramic factory waste, leather factory waste, and stone cutting waste. The influence of the extractants on heavy metal release from these ISWs was in the following descending order: citric acid oxalic acid nitric acid≥ sulfuric acid Ca Cl2. Addition of clay minerals and NPs as adsorbents decreased heavy metal release, which was significantly lower in NP-treated wastes than in the clay mineral-treated wastes. On the other hand, the presence of organic and inorganic acids increased heavy metal adsorption by NPs and clay minerals. These results suggest that NPs can be applied successfully in waste remediation,and organic and inorganic acids play an important role in the removal of heavy metals from the studied adsorbents.