Synthesis of isotopically modified ZnO nanoparticles and their potential as nanotoxicity tracers

Understanding the behavior of engineered nanoparticles in the environment and within organisms is perhaps the biggest obstacle to the safe development of nanotechnologies. Reliable tracing is a particular issue for nanoparticles such as ZnO, because Zn is an essential element and a common pollutant thus present at elevated background concentrations. We synthesized isotopically enriched (89.6%) with a rare isotope of Zn (⁶⁷Zn) ZnO nanoparticles and measured the uptake of ⁶⁷Zn by L. stagnalis exposed to diatoms amended with the particles. Stable isotope technique is sufficiently sensitive to determine the uptake of Zn at an exposure equivalent to lower concentration range (<15 μg g⁻¹). Without a tracer, detection of newly accumulated Zn is significant at Zn exposure concentration only above 5000 μg g⁻¹ which represents some of the most contaminated Zn conditions. Only by using a tracer we can study Zn uptake at a range of environmentally realistic exposure conditions.     

基于虚拟耕地方法的中国粮食生产布局诊断

为研究我国区域粮食生产空间布局问题，运用虚拟耕地方法和对比方法对我国粮食生产空间布局进行诊断。首先，用人均农村人口粮食产量的虚拟耕地量表征我国粮食生产的空间布局现状，发现其存在“高值区相对集中，低值区相对分散”、区域间差异明显的特点。高值区集中于东北和内蒙古、长江中下游以及江南丘陵的北部地区；其次，主要从水土资源、自然灾害等方面构建包含8个具体指标的评价指标体系对我国31个省级行政区的粮食生产适宜度进行定量评价。发现我国不同区域间的粮食生产适宜度存在显著差异，区域粮食生产适宜度整体上呈现东高西低的空间分布规律，其中，高适宜度区域主要分布在我国的东北、黄淮海、华中、华南和西南各省区，低适宜度区域主要分布在西北、华北和东南沿海的福建、江西等省区；最后，构建粮食生产布局协调指数作为我国不同区域粮食生产布局调整的依据，发现北方11个省区粮食生产布局过密，南方16个省区粮食生产布局过疏。研究方法具有一定的创新性，但是，在粮食生产适应性评价的指标选择等方面尚存在明显的不足，研究结果和结论都有待进一步完善。     

Amendment of arsenic and chromium polluted soil from wood preservation by iron residues from water treatment

An iron-rich water treatment residue (WTR) consisting mainly of ferrihydrite was used for immobilization of arsenic and chromium in a soil contaminated by wood preservatives. A leaching batch experiment was conducted using two soils, a highly contaminated soil (1033 mg kg⁻¹ As and 371 mg kg⁻¹ Cr) and slightly contaminated soil (225 mg kg⁻¹ As and 27 mg kg⁻¹ Cr). Compared to an untreated reference soil, amendment with 5% WTR reduced leaching in the highly contaminated soil by 91% for Cr and 98% for As. No aging effect was observed after 103 d. In a small field experiment, soil was mixed with 2.5% WTR in situ. Pore water was extracted during 3 years from the amended soil and a control site. Pore water arsenic concentrations in the amended soil were more than two orders of magnitude lower than in the control for the upper samplers. An increased release of arsenic was observed during winter in both fields, mostly in the deepest samplers. This is likely due to the formation of a pseudo-gley because of precipitation surplus. Stabilization of arsenic and chromium contaminated soil using WTR is a promising method but the transformation of ferrihydrite in soil proves a concern in case of waterlogged soils. Still the amendment minimized the leaching of arsenic, even in cases of seasonal releases.     

浅谈燃气发电厂如何实施清洁生产

文章通过对某燃气发电厂实施安装投入运行溴冷机、改造增压机控制系统、改造厂房冷却水回收系统、改造余热锅炉尾部加装换热器、实现余热再利用等清洁生产的技术措施,实施小指标考核等清洁生产的管理措施,取得较好的节能降耗效果。这些措施为同类企业实施清洁生产提供了经验,并为企业降低能耗指标提供了技术支持。     

An Environmental Kuznets Curve for N2O emissions in Germany: an ARDL approach

This paper analyses the relationship between nitrous oxide (N₂O) emissions, economic growth, agricultural land used and exports in Germany. We use time‐series data between 1970 and 2012 and the Autoregressive Distributed Lag (ARDL) methodology to test for cointegration in the long run. Results show that there is a quadratic long run relationship between N₂O emissions and economic growth, confirming the existence of an Environmental Kuznets Curve (EKC) for Germany. Agricultural land area affects N₂O emissions positively, whereas exports affect emissions negatively. The turning point is $27,880, which is within the sample and implies that Germany is in the decreasing part of the curve of environmental degradation. The paper shows that, contrary to testing the EKC in less developed countries, mitigation of N₂O emissions does not negatively affect growth in Germany. As such, it is feasible to undertake any conservative policy in order to reduce emissions without major consequences on economic sectors.     

几种典型红壤模拟降雨条件下的泥沙特征研究

泥沙是土壤侵蚀过程的产物,直接反映了土壤的侵蚀特征。本文利用人工模拟降雨,研究了南方几种典型母质发育红壤侵蚀泥沙的颗粒分布特征、不同粒级中胶结物质的种类和含量。研究结果表明,径流优先选择携带0.002~0.02 mm颗粒,该级别颗粒占泥沙总量的26.68%~60.33%。粘粒含量高的第四纪粘土红壤,泥沙中粗颗粒含量较高,且多为较稳定的团聚体;沙粒和粉粒含量较高的页岩红壤和花岗岩红壤侵蚀泥沙中单粒含量较高,且泥沙分散后粉粒和粘粒的含量高于原土壤。花岗岩红壤侵蚀泥沙中Fe_d,Al_d,Al_o和Si_o含量随泥沙粒径的增大而降低,而泥质页岩红壤和第四纪粘土红壤中,Fe_d,Al_d,Al_o含量随粒径增大而增加,因此其粗粒径泥沙具有较强的稳定性。侵蚀泥沙对有机质有富集作用,泥质页岩红壤和第四纪粘土红壤的粗颗粒对有机质的富集作用强于细颗粒。     

工业污染源产排污系数存在问题分析及修订建议

通过对基层环境统计部门工业源产排污系数实际应用调研,结合当前环境保护重点工作和相关资料查阅等,分析了工业污染源产排污系数存在的主要问题:部分工业源产排污系数缺失,部分工业源产排污系数与实际偏差较大等。针对存在的主要问题提出了有优先顺序的修订建议,以期对第二次全国污染源普查工作提供有益参考。     

钼酸铵的清洁生产工艺

以酸-盐预处理-离子交换组合工艺替代传统工艺,提出了氧化钼、氨生产钼酸铵清洁生产工艺.该工艺采用液、渣双循环代替液单循环,以电锅炉替换燃煤锅炉.含氨废气采用酸性生产废水吸收,产生的高浓度含氨废液进行汽提处理,分离出的氨回用于生产,废液和含氨废气处理后均达标排放,基本实现了钼酸铵的清洁生产.采用该清洁生产工艺生产钼酸铵,...     

Differentiation of nitrous oxide emission factors for agricultural soils

Nitrous oxide (N₂O) direct soil emissions from agriculture are often estimated using the default IPCC emission factor (EF) of 1%. However, a large variation in EFs exists due to differences in environment, crops and management. We developed an approach to determine N₂O EFs that depend on N-input sources and environmental factors. The starting point of the method was a monitoring study in which an EF of 1% was found. The conditions of this experiment were set as the reference from which the effects of 16 sources of N input, three soil types, two land-use types and annual precipitation on the N₂O EF were estimated. The derived EF inference scheme performed on average better than the default IPCC EF. The use of differentiated EFs, including different regional conditions, allows accounting for the effects of more mitigation measures and offers European countries a possibility to use a Tier 2 approach.