Impact significance determination—Designing an approach

The question of how best to go about determining the significance of impacts has, to date, only been addressed in a partial and preliminary way. The assumption tends to be made that it is either only necessary to provide explicit, justified reasons for a judgment about significance and/or to explicitly apply a prescribed procedure—a procedure usually involving the staged application of thresholds and/or criteria. The detailed attributes, strengths and limitations of such approaches and possible alternative approaches have yet to be explored systematically.This article addresses these deficiencies by analyzing the characteristics, specific methods and positive and negative tendencies of three general impact significance determination approaches—the technical approach, the collaborative approach and the reasoned argumentation approach. A range of potential composite approaches are also described. With an enhanced understanding of these approaches, together with potential combinations, EIA practitioners and other EIA participants can be in a better position to select an approach appropriate to their needs, to reinforce the positive tendencies and offset the negative tendencies of the selected approach and to combine the best qualities of more than one approach.     

LDPE/EPDM Multilayer Films Containing Recycled LDPE for Greenhouse Applications

In this paper the reuse of recycled LDPE in combination with the incorporation of EPDM modifier in the production of greenhouse films has been investigated. A three-layer film (60-100-40 micron thickness) containing recycled LDPE in the middle layer and a high UV-stabilized 40-micron outer layer was developed and proven to be commercially successful. Films with 25% and 50% recycled material content were produced. The effect of natural weathering on the film properties over a period of 15 months has been observed. Changes in physical and mechanical property were determined. The addition of EPDM to the raw resin was found to improve the extrudability of the compound and improve the weather resistivity of the film. The EPDM-modified films containing 25% to 50% recycled material retained approximately 95% and 75%, respectively, of their original extensibility after 9 months' exposure to natural weathering. Optimization of EPDM and UV stabilizer concentration was carried out to develop a balanced film with excellent mechanical and physical properties and resistance to weathering conditions. The use of UV stabilizer concentrations slightly higher than commercial practice in the outer layer of the multilayer film can be justified by the cost reduction by the incorporation of recycled LDPE materials.     

Distribution, sources and potential toxicological significance of polycyclic aromatic hydrocarbons(PAHs) in Guanting Reservoir sediments, China

The Guanting Reservoir lost its function as the second biggest drinking water source for Beijing due to the pollutions from the upstream flow of Yongding River in 1997. From 1998, lots of studies were carryied out to renew the function of Guanting Reservoir as domestic drinking water source before 2008 Olympic Games. This is the first time that polycyclic aromatic hydrocarbon concentrations in the surface sediment of Guanting Reservoir have been analyzed. A distinctive spatial distribution of PAHs was observed. Sediments from four sites along Inlet of Yongding River to reservoir bam had PAHs concentrations of 1377--2855 μg/g dw in descending order. The composition of PAHs is investigated and used to assess patrogenic,combustion and naturally derived of the sediments samples of Guanting Reservoir. Special PAHs ratios, such as phenanthrene/anthracene(P/A) and fluoranthene/pyrene(Fl/Pyr) were calculated to assess the relative importance of different origins. The data confirmed a relatively high level of petrogenic contamination in four sites. These high PAHs levels were associated with the input of untreated and partially treated industrial sewage. In addition, the concentrations of PAHs compounds of samples indicated that sediments of reservoir were most likely to pose potential biological impairment.     

乌江流域沉积岩风化过程中铀的富集与释放

以乌江流域石灰岩、白云质灰岩、白云岩、硅质岩、黑色页岩和紫色砂岩等典型岩石的13条风化剖面为对象,运用相关分析和质量平衡计算方法,研究了这些岩石风化过程中铀(U)的富集与释放及其对河水U分布的影响,旨在增进对U生物地球化学循环的了解,也为流域U污染防治提供依据.结果表明,①乌江流域风化物和土壤中U的富集程度基本上高于上陆壳(upper continental crust,UCC)、中国土壤(China soil,CS)和世界土壤(world soil,WS);②U的富集和释放能力与母岩U含量以及风化剖面中粘土矿物和铁氧化物/氢氧化物含量及吸附能力有关;③石灰岩以及少量白云岩和碎屑岩风化过程中U的释放对河水U的分布特征具有重要的控制作用.     

历史性转变——20o6中国环境保护评述

2006年,从中央到地方都大幅度强化了环境保护的施政力度。中央提出了环境保护与经济增长要并重、同步和综合的要求,这被称为“环境保护的历史性转变”。与此同时,国家出台了20多项以环境保护为重要内容或与环境保护有关的产业政策和其他经济政策。新成立了11个环境保护和核安全的区域督查机构,层层下达了主要污染物排放消减指标。各地也把主要精力放在了推动新型工业化和城市化进程上,出台了大量加强和支持环境保护的经济政策和管理措施。     

Impact of Criticism of Null-Hypothesis Significance Testing on Statistical Reporting Practices in Conservation Biology

Abstract:  Over the last decade, criticisms of null-hypothesis significance testing have grown dramatically, and several alternative practices, such as confidence intervals, information theoretic, and Bayesian methods, have been advocated. Have these calls for change had an impact on the statistical reporting practices in conservation biology? In 2000 and 2001, 92% of sampled articles in Conservation Biology and Biological Conservation reported results of null-hypothesis tests. In 2005 this figure dropped to 78%. There were corresponding increases in the use of confidence intervals, information theoretic, and Bayesian techniques. Of those articles reporting null-hypothesis testing—which still easily constitute the majority—very few report statistical power (8%) and many misinterpret statistical nonsignificance as evidence for no effect (63%). Overall, results of our survey show some improvements in statistical practice, but further efforts are clearly required to move the discipline toward improved practices.     

黔中白云岩风化剖面微量元素的地球化学特征

本研究是为了探讨微量元素在化学风化作用下的迁移特征及分布规律并讨论碳酸盐岩地区红色风化壳的物源问题。我们选择了贵州省遵义市新浦镇的一处发育完好的原生白云岩上覆红土剖面作为研究的对象。以Zr作为不活化元素,我们得到以下的认识:1)该白云岩上覆红土剖面是原地形成的淋滤剖面,微量元素的迁移系数在红土剖面中的变化都具有很好的规律性。元素对Nb-Ta、Zr-Hf和Y-Yb的相关性很强,其可以作为上覆土层物质非多来源的证据,而单一物源与下伏岩石高度相关,那么可以推断所研究的土壤来源于下覆碳酸盐岩的风化。2)在整个剖面中,大部分微量元素在风化过程中都表现出富集的特性,尤其在岩-土界面处达到最大化,这显示出了风化淋滤的过程。Nb、Ta、V和Hf是相对不活化的元素。3)轻稀土元素在岩土界面的富集系数是大于重稀土元素的,这表明轻稀土元素在淋滤过程中更易于迁移。此外,铁质壳对相关微量元素有着富集的作用。总之,本次的研究结果对探讨喀斯特地区红土型风化壳的物质来源问题有着重要的指示意义。     

环境污染加剧石质文物风化:机理、过程及防护措施

石质文物的风化问题由来已久,在影响石质文物风化的各类因素中,环境恶化对石质文物的风化影响日益严重,但现有研究大多忽略了环境污染加剧的影响。在此背景下,本文从酸性气体排放、温度效应和水体污染三个方面阐述了环境污染加剧对石质文物风化的影响和作用机理,并对现有石质文物的防护措施进行综合比较分析,提出石质文物的保护建议和措施,为新形势下石质文物的保护研究提供新的思路。     

韩江流域河水地球化学特征与硅酸盐岩风化——风化过程硫酸作用

流域岩石化学风化是全球碳循环的重要环节之一,硅酸盐岩风化过程消耗大气CO_2,是在地质时间尺度上调节大气CO_2浓度的重要机制。本工作在对我国东南花岗岩地区流经典型的硅酸盐岩地质背景河流——韩江流域河流水化学组成研究的基础上,分析和定量计算了河流水体主要物质来源,并对硫酸参与岩石风化和碳循环过程的作用进行了分析,进而对韩江流域岩石风化速率及其大气CO_2消耗通量进行了估算。结果表明,韩江流域河流主离子组成主要来源于硅酸盐岩和碳酸盐岩风化,并计算得出约41%的硫酸根离子来自于大气降水;流域碳酸盐岩的风化速率为21.7 t/(km~2·a),硅酸盐岩为18.9 t/(km~2·a)。硫酸参与岩石风化提供的离子贡献占流域岩石风化提供总离子量的65.9%;流域风化带来的CO_2消耗速率被高估了约61%。     

基于生物标志物法的珠江流域有机碳溯源及DIC施肥效应研究

内源有机碳由地表水体水生光合固定DIC产生,是岩石风化碳汇的重要组成部分。为准确区分河陆地流水体中的内源有机碳及计算其所占比例,本文选取珠江流域作为研究区,通过不同季节的野外采样调查,利用类脂生物标志物法,结合传统水化学特征,揭示河流中有机碳的来源差异;最终根据有机碳的时空分布规律与水-岩-土-气-生相互作用分析,明确流域岩性及气候变化对碳汇的影响。结果表明:(1)珠江流域水体中冬季和夏季内源有机碳占总有机碳比例的平均值分别为65%和54%,表明水生植物光合作用导致的初级生产力的重要性;(2)内源有机碳比例和水生藻类生物量与DIC浓度和呈现出显著的正相关关系,表明DIC对水生植物光合作用具有施肥效应;(3)雨季因降雨稀释DIC浓度和冲刷外源有机质,对水生植物的施肥效应减弱,生成的内源有机质减少,且携带的外源有机质增加,导致内源比例减少;(4)高悬浮质(TSS)可以遮挡水体表层太阳光,减弱水生光合作用强度,降低内源有机碳的形成;但在TSS浓度比较低的情况下,其对水生植物生长繁殖的影响则体现在为其提供空间和营养物,从而增加水生藻类生物量及内源有机碳比例。