广东省土地资源可持续利用评价研究

基于广东省城市化进程中土地资源利用之特点，利用熵权技术和线性加成技术建立了广东省土地资源可持续利用的评价体系，并对广东省1992～2002年期间土地利用的基本状况进行了实证分析，研究表明：广东省土地资源利用状况从总体上看是趋好的，在经历了1992～1995年的弱可持续之后，目前已进入良性发展阶段，其经济指标和社会指标均处于良好发展势头．但资源和环境指标在2000年后呈明显下滑趋势。这应该引起政府及有关部门高度重视。     

美国州法中的内径流水权及其优先权日问题

美国水资源的所有权属于各州 ,是一种公有的资源。法律上的水权 ,是水的使用权 ,主要包括私人所有的先占权水权、岸边权水权。在美国西部各州的水权系统中 ,有一种水权现在可以在私法框架中协调环境保护目标、各种取水权人的取水需求 ,这两者之间的冲突。这就是现在美国学术界广泛关注的内径流水权。内径流水权可以在私法领域保护水流的天然禀赋 ,并且排除政府以环境法为理由介入水事争端。随着环境主义在美国的破产[1] ,美国西部开始了大规模的水权裁决活动 ,通过水法院或者行政机构确认私有水权的优先权日 ,从而确立水权的优先权序列。这样水权就会真正成为属于分散的个体的、排他性的财产权。优先权日在先的水权将在枯水季节排除他人的取水权或者其他种类的用水权。因此 ,确立内径流水权在这个优先权序列中的地位 ,是环境保护目标在私法体系中 ,而不是在效率低下的各种环境保护法中 ,长久地得到维护的关键。内径流水权优先权日有 (1)判例法认定的日期 ;(2 )法律规定的日期 ;(3)转化生成的日期。在先占原则框架中扩张这种财产权可以更大程度地排除环境法的适用范围。     

防灾工程动态投资决策方法初探

本文提出了防灾工程的抗力、灾损度和灾害的灾度、灾害势以及动态决策准则等概念,基于现代控制理论,初步建立了防灾工程动态投资决策的一般方法,并对其进行了理论分析和研究。这里的决策包括防灾工程的初始投资(或设防水平)决策及其防灾规划期(或寿命期)内的防灾减灾维护投资(或维护水平)决策.文中还给出了算例,对上述方法进行了应用。算例结果表明,本文提出的防灾工程动态投资决策方法具有比较显著的经济效益。     

延吉市产业结构调整与知识产业发展

延吉市土地面积小 ,水土资源紧张 ,人口与环境压力较大 ,但智力资源丰富。延吉市已经形成以二、三产业为主导的产业体系 ,但产业内部存在结构性问题。文章认为产业结构调整与发展知识产业相结合是实现城市可持续发展的重要途径 ,进而探讨了延吉市产业结构调整思路 ,提出知识产业发展方向。     

河北省水文地质环境变化及其脆弱性分析

河北省是我国乃至世界水文地质环境恶化最严重的地区之一。本文通过分析生态环境和水文地质环境变化的过程和致灾现状 ,指出了其脆弱性累进的原因 ,并提出了遏制环境恶化 ,减轻灾害影响与损失 ,调整人类行为的对策与建议     

The effects of elevated CO2 on clonal growth and nutrient content of submerge plant Vallisneria spinulosa

An approximately four months long glasshouse experiment was conducted to examine the effects of elevated carbon dioxide (CO(2)) concentration (1,000 +/- 50 micromol mol(-1)) in the atmosphere on biomass accumulation and allocation pattern, clonal growth and nitrogen (N), phosphorus (P) accumulation by the submerged plant Vallisneria spinulosa Yan. Elevated CO(2) significantly increased V. spinulosa total fresh biomass ( approximately 130%) after 120 days, due to more biomass accumulation in all morphological organs than in those at ambient CO(2) (390 +/- 20 micromol mol(-1)). About 75% of the additional total biomass at elevated CO(2) was accounted for by leaf and rhizome (above ground) biomass and only 25% of it belonged to root and turion (below ground). However, the turions biomass exhibited a greater increase rate than that of organ above ground, which caused reduction in the above/below ground biomass ratio. The clonal growth of V. spinulosa responded positively to elevated CO(2). The number of primary ramets increased up to 1.4-folds at elevated CO(2) and induced a dense growth pattern. For nutrients absorption, concentration of N in leaf and in turion was significantly (p 相似文献   

An assessment of the risks associated with polychlorinated biphenyls found in the stomach contents of stranded Indo-Pacific Humpback Dolphins (Sousa chinensis) and Finless Porpoises (Neophocaena phocaenoides) from Hong Kong waters

The risks to Indo-Pacific Humpback Dolphins and Finless Porpoises associated with polychlorinated biphenyls (PCBs) were assessed. Stomach contents from twelve stranded Humpback Dolphins and sixteen stranded Finless Porpoises were collected. Concentrations of total and isomer-specific PCBs in the stomach contents were determined using dual-column gas chromatography equipped with electron capture detectors (GC-ECD). Risks due to the PCBs were assessed in three scenarios, based on total PCBs (summation of 41 PCB congeners), total toxicity equivalency (TEQs) and PCB 118, using the toxicity reference values (TRVs) as the threshold effects benchmarks. The calculated risk quotients (RQs) showed that risks due to PCBs were generally low or negligible. Specifically, RQs from total TEQs and total PCBs for Finless Porpoises are below one, suggesting that PCBs should be a low risk for the Finless Porpoise in Hong Kong waters. However, the Humpback Dolphin has RQs larger than 1 for total TEQs and total PCBs when the 95th percentile data were used in the evaluation. This indicates that further investigation may be needed to examine more closely the potential impact of toxic contaminants in the habitat of the Humpback Dolphin.     

Potential contributions of clay minerals and organic matter to pentachlorophenol retention in soils

Sorption of pentachlorophenol (PCP) by pure minerals and humic acids were measured to obtain additional perspective on the potential contributions of both clay minerals and soil organic matter (SOM) to contaminants retention in soils. Four types of common soil minerals and two kinds of humic acids (HAs) were tested. The sorption affinity for PCP conformed to an order of HAs > K-montmorillonite > Ca-montmorillonite > goethite > kaolinite. Such a difference in sorption capacity could be attributed to the crucial control of HAs. Clay minerals also had their contribution, especially K-montmorillonite, which played an important, if not dominant, role in the controlling process of PCP sorption. By removing 80% (on average) of the organic carbon from the soils with H(2)O(2), the sorption decreased by an average of 50%. The sorption reversibility had been greatly favored as well. Considering the uncharged mineral fractions in soil before and after H(2)O(2)-treated, the main variation in sorption behavior of the soil might thus be related to the removed organic carbon and the reduced pH. This testified rightly the interactive effect of SOM and clay minerals on PCP sorption as a function of pH.     

Effect of copper on the adsorption of p-nitrophenol onto soils

The effect of copper on adsorption of p-nitrophenol on two typical Chinese soils was investigated using a batch-equilibration method. Adsorption experiments were carried out when both copper and p-nitrophenol were adsorbed simultaneously, and when copper was previously adsorbed on soils. It was observed that adsorption of p-nitrophenol decreased with increasing copper concentrations thereby indicating a competition between copper and p-nitrophenol for occupying the adsorption sites on soils. Moisture increased the hydrated sphere and the acidity of water surrounding the cation, which further reduced the adsorption of p-nitrophenol. Fourier transform infrared spectroscopy study provided the direct evidence for the coordination of p-nitrophenol sorbed by soils with metal cation in n-hexane system. It was observed that the perturbations included a red shift of the nu(asym) (NO) band, a concomitant blue-shift of the nu(sym) (NO) band and a blue-shift of C-N band when compared with the infrared spectra obtained from water solution.     

Removal of cyanobacterial blooms in Taihu Lake using local soils. I. Equilibrium and kinetic screening on the flocculation of Microcystis aeruginosa using commercially available clays and minerals

Algal removal abilities of 26 clays/minerals were classified into three categories according to the 8-h equilibrium removal efficiency (Q8h) and removal rate at a clay loading of 0.7 g/L. Type I clays (sepiolite, talc, ferric oxide, and kaolinite) had a Q8h > 90%, a t50 (time needed to remove 50% of the algae) < 15 min, and a t80 < 2.5 h. Type II clays (6 clays) had a Q8h 50-90%, a t50 < 2.5 h, and a t80 > 2.5 h. Type III clays (14 clays) with Q8h < 50%, t50 > 8 h and t80 > 14 h had no practical value in removal of algal blooms. When the clay loading was reduced to 0.2 g/L, Q8h for all the 25 materials decreased to below 60%, except for sepiolite whose Q8h remained about 97%. The high efficiency for sepiolite to flocculate M. aeruginosa cells in freshwaters was due to the mechanism of netting and bridging effect.