Model evaluation of the phytoextraction potential of heavy metal hyperaccumulators and non-hyperaccumulators

Evaluation of the remediation ability of zinc/cadmium in hyper- and non-hyperaccumulator plant species through greenhouse studies is limited. To bridge the gap between greenhouse studies and field applications for phytoextraction, we used published data to examine the partitioning of heavy metals between plants and soil (defined as the bioconcentration factor). We compared the remediation ability of the Zn/Cd hyperaccumulators Thlaspi caerulescens and Arabidopsis halleri and the non-hyperaccumulators Nicotiana tabacum and Brassica juncea using a hierarchical linear model (HLM). A recursive algorithm was then used to evaluate how many harvest cycles were required to clean a contaminated site to meet Taiwan Environmental Protection Agency regulations. Despite the high bioconcentration factor of both hyperaccumulators, metal removal was still limited because of the plants' small biomass. Simulation with N. tabacum and the Cadmium model suggests further study and development of plants with high biomass and improved phytoextraction potential for use in environmental cleanup.     

Nanofiltration of concentrated and salted tuna cooking juices

Tuna cooking juice from a Tunisian tuna-processing unit has a high level of polluting load: chemical oxygen demand (COD) is comprised between 4 and 20 g L⁻¹, nitrogen kjedahl (NK) between 0.6 and 3 g L⁻¹ and dry matter between 120 and 160 g L⁻¹. The juice has thus to be treated before being rejected into the environment. This paper considers the nanofiltration (NF) of these concentrated organic/inorganic mixtures using an AFC 30 (NF) membrane. The work focusses on the effect of organic and inorganic matters on the permeate flux and rejections of these matters. For this purpose, mixtures of salt and organic pollution (COD), used as model solutions, were prepared by the dilution of a typical industrial tuna cooking juice. The permeate flux was found to decrease when salt and organic matter concentrations increase. The recovery rate in organic matter decreases with increasing salt or organic matter content and the recovery rate of salt decreases when the COD concentration increases.     

国外流域管理的成功经验对雅砻江流域管理的启示

世界各国对流域管理的不断探索，大大丰富了流域管理的理论和实践，流域管理已成为国家和地区水资源管理的一种行之有效的模式。我国的流域管理尚处于最初的探索阶段，如何借鉴国外流域管理的成功经验，形成有效的流域管理模式已成为我国水资源管理的主要任务之一。为了给国内流域管理实践提供一些有益的借鉴，分析总结了具有代表性的美国田纳西河流域管理模式、澳大利亚墨累 达令河流域管理模式和英国泰晤士河流域管理模式的成功经验和存在的问题。以雅砻江流域水电开发为实例，在对该流域的实际情况进行全面分析的基础上，将该流域与上述三条流域进行比较，充分借鉴三条流域管理模式成功经验，提出了雅砻江流域管理的相关对策和建议。     

浅议“环境试验设备技术条件”新标准

2006年至2008年，89版“环境试验设备技术条件”相继修订发布。本文着重阐述了“环境试验设备技术条件”新旧标准的变化及其与GB／T5170的关系。     

The electron density distribution in pyridinium and bipyridylium compounds and its relevance to their adsorption by expanding lattice clays

Abstract

Charge distributions in 1, 1'‐ethylene‐2, 2'‐bipyridylium (diquat), 1,1'‐dimethyl‐4,4'‐bipyridylium (paraquat) and 1‐methylpyridinium organocations were calculated by a Complete Neglect of Differential Overlap semi‐empirical quantum mechanical procedure. The data show that the positive charges in the organocations are distributed around the molecules and are greatest in the positions ortho and para to the heterocyclic nitrogen atoms. Earlier interpretations of the mechanisms of adsorption of paraquat and diquat by soils and clays assumed that the charges were located in the heterocyclic nitrogen atoms. Here some consideration is given to the influence of the charge delocalizations on the processes of adsorption by montmorillonite and vermiculite clay preparations.     

煤矿救援队伍业务管理系统研究

为了改善救援队伍业务管理模式,提高煤矿救援队伍的业务管理能力,利用救护队现有的计算机设备,以Windows Server 2003系统和北京龙软科技发展有限公司Longruan GIS 3.0为平台,以Visual C++6.0和SQL Server 2000为开发工具,采用多层次的Client/Server结构,在面向对象思想指导下设计与实现的煤矿救援队伍业务管理系统,文章介绍了业务管理系统的前台软件开发和后台数据库开发的设计思想和步骤。现场应用证明,该系统能够为煤矿救援队业务管理提供强有力的技术支持,有利于提高煤矿救援队管理人员的业务能力。     

Analysis of a Farquhar-von Caemmerer-Berry leaf-level photosynthetic rate model for Populus tremuloides in the context of modeling and measurement limitations

The balance of mechanistic detail with mathematical simplicity contributes to the broad use of the Farquhar, von Caemmerer and Berry (FvCB) photosynthetic rate model. Here the FvCB model was coupled with a stomatal conductance model to form an [A,g_s] model, and parameterized for mature Populus tremuloides leaves under varying CO₂ and temperature levels. Data were selected to be within typical forest light, CO₂ and temperature ranges, reducing artifacts associated with data collected at extreme values. The error between model-predicted photosynthetic rate (A) and A data was measured in three ways and found to be up to three times greater for each of two independent data sets than for a base-line evaluation using parameterization data. The evaluation methods used here apply to comparisons of model validation results among data sets varying in number and distribution of data, as well as to performance comparisons of [A,g_s] models differing in internal-process components.     

Identification of microcystins from three collection strains of Microcystis aeruginosa

Microcystins (MCs) are toxic cyclic heptapeptides produced by various cyanobacteria genera, especially Microcystis. We identified 10 out of 12 MCs produced by three Microcystis aeruginosa strains from cyanobacteria collections, UTEX 2666, UTEX 2670 and UAM 1303, by using two analytical methods: Matrix-assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF/MS) and HPLC Photodiode Array Detector coupled to a hybrid Quadrupole Time of Flight Mass Spectrometry (HPLC-PDA-QTOF/MS). MALDI-TOF/MS failed to detect non-polar MCs, such as MC-LY and MC-LW. HPLC-QTOF/MS permitted the accurate identification of most MCs present in methanolic extracts. Besides, three new MCs, namely: [D-Glu(OCH₃)⁶, D-Asp³] MC-LAba, MC-YL and MC-YM were detected by HPLC-QTOF/MS.     

城市总体规划环评指标体系的建立及其应用

本研究首先介绍了DPSIR模型构建的原理,接着以合肥市为对象,从驱动力、压力、状态、影响、响应5个方面来构建的共36个指标,并采用层次分析法对指标权重的确定和多级灰色关联分析对指标进行综合评价,得出评价结果。合肥市在2004~2005年处于较低可持续发展水平(0.3398、0.3876)、在2010年处于中等可持续发展水平(0.5369)、在2015年处于较高可持续发展水平(0.6016)、在2020年处于较高可持续发展水平(0.7847),该预测评价结果与合肥市城市可持续发展趋势相符。最后采用改进熵值法验证多级灰色关联综合分析结论,计算得出的结果表明,该两种方法评价结论基本相同。因此,本研究对城市总体规划环境影响评价的评价方法的建立与完善,有着较强的实践意义和参考价值。     

Tracking nitrogen losses in a greenhouse crop rotation experiment in North China using the EU-Rotate_N simulation model

Vegetable production in China is associated with high inputs of nitrogen, posing a risk of losses to the environment. Organic matter mineralisation is a considerable source of nitrogen (N) which is hard to quantify. In a two-year greenhouse cucumber experiment with different N treatments in North China, non-observed pathways of the N cycle were estimated using the EU-Rotate_N simulation model. EU-Rotate_N was calibrated against crop dry matter and soil moisture data to predict crop N uptake, soil mineral N contents, N mineralisation and N loss. Crop N uptake (Modelling Efficiencies (ME) between 0.80 and 0.92) and soil mineral N contents in different soil layers (ME between 0.24 and 0.74) were satisfactorily simulated by the model for all N treatments except for the traditional N management. The model predicted high N mineralisation rates and N leaching losses, suggesting that previously published estimates of N leaching for these production systems strongly underestimated the mineralisation of N from organic matter.