Sediment integrative assessment of the Bay of Cádiz (Spain): An ecotoxicological and chemical approach

This study consisted of the sediment toxicity assessment of the Bay of Cádiz based on two endpoints: growth inhibition for Cylindrotheca closterium (benthic microalgae) and fecundity inhibition for Tisbe battagliai (harpacticoid copepod). A new methodology to eliminate (but not as storage technique) the autochthonous biota present in the sediment samples by immersing them in liquid nitrogen (? 196 °C) was also assessed. Sediment toxicity data showed different toxicity levels for both organisms. In general, T. battagliai was more sensitive; however a good correlation (r = 0.75; p  < 0.05) between sediment toxicity results for both species was found. Data in pore water (pH, redox potential, and toxicity for microalgae and copepod) and sediment (pH, redox potential, organic carbon, and metal concentrations) demonstrated that ultra-freezing did not alter sample characteristics; thus, this technique can be adopted as a pre-treatment in whole-sediment toxicity tests in order to avoid misleading results due to presence of autochthonous biota. Multivariate statistical analysis such as cluster and principal component analysis using chemical and ecotoxicological data were employed. Silt and organic matter percentage and lead concentration were found to be the factors that explain about 77% of sediment toxicity in the Bay of Cádiz. Assay methodology determined in this study for both assayed species is considered adequate to be used in sediment toxicity monitoring programs. Results obtained using both species show that the Bay of Cádiz can be considered a moderately polluted zone.     

基于ARCGIS的长株潭城市群核心区环境容量评价

区域环境容量评价与分析是区域合理开发和布局的重要依据。在ARCGIS技术的支持下,首先对长株潭城市群核心区大气、水和土壤环境容量分别进行评价与分析,形成等级图,然后,进行各因素空间叠加,经综合分析与评价,将核心区划分为5个区域：优良区、合理区、饱和区、超饱和区、过度饱和区,并且还提出了相应的建议与对策。其主旨是为促进该区域空间科学开发与布局、生态环境的合理保护,对规范长株潭城市群“两型社会”建设理性发展具有非常重要的意义,并提供参考依据     

昆山市生态系统服务价值变化研究

在Constanza的生态系统服务价值理论的基础上,计算了1994－2002年昆山市生态系统服务价值的变化。建设用地对耕地和水域面积的占用,引起了昆山市的生态系统服务价值逐渐下降： 9年间生态系统服务价值（ESV）总量下降了8.9%,人均占有量（Ave(ESV)）下降了13.0%。各种土地利用方式的生态系统服务价值的弹性系数都小于1。水域面积的变化则对生态系统服务价值变化起到放大作用。耕地面积的变化主要是影响昆山市的粮食安全问题,而水域的变化则在更大程度上影响生态系统服务功能方面。     

Geochemistry and bioavailability of metals in sediments from northern San Francisco Bay

In this study, metals (Be, Cr, Mn, Fe, Ni, Cu, Zn, Ag, Cd, Pb and Hg) in the fine-grained fraction (<63 microm) from 12 sites at different locations in northern San Francisco Bay over a year period from March 2000 to March 2001 were analyzed after acid extraction. The results showed that metal concentrations in the sediments varied from site to site, whereas some of them were found elevated with respect to the sediment of Tomales Bay, CA, which has little contamination history, indicating an enrichment of the metals in the sediment samples analyzed. Sediment toxicity and bioaccumulation evaluation by a clam species, Macoma nasuta, exposed to the sediment samples collected from the six sampling sites was carried out. The results showed that the sediment samples tested significantly reduced clam survival. Toxicity of the sediments to the clam was, in part, related to elevated metal concentrations in the sediments. In order to examine geochemistry of the metals and to understand potential correlations between metal concentrations and geochemical matrix elements of the sediments, bioavailability and toxicity of the metals, detailed analysis of metal concentrations associated with total organic carbon and the Fe-oxy-hydroxides in the sediment samples was performed. The analysis showed that sediment geochemistry appeared to influence metal bioavailability and may have important impacts on the toxicity of these metals to the clam.     

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。     

Floating Population Increase and Its Influence on the Urban Population Situation:A Case Study in Beijing

1 BACKGROUND OF FLOATING POPULATIONIN CHINAChina's urbanization process was influenced mainly bythe government interventions before the adoption of thesocial and economic reform started in 1978. Since thefoundation of the People's Republic of China, thegovernment had strictly controlled the internal migration,especially from rural to urban areas. The ability of thegovernment to make a strong impact on the migrationand urbanization was realized by the household registrationsyste…     

Analysis of Environmental and Socio-economic Determinants Affecting Population Longevity Level at County Level in China

INTRODUCTIONIn recent thirty years, due to the decreasing fertility andincreasing life expectancy, China's population is aging ata very rapid pace and the elderly population size is keepingon growing. During the dramatic aging progress, the oldestold group in China is catching our eyes. More and moreold people of China are becoming the oldest old. Theextremely old population (aged 80 and above) is increasingat 5.1% annually, while the old population above 65 isincreasing at 2.9%, and the…     

上海市工业区绿地植物对重金属吸收及富集的研究

由于缺乏对上海工业区重金属积累植物的研究,通过野外采样和统计分析方法,研究上海主要工业区土壤中Zn、Cu、Pb和Cd 4种重金属的含量及其在20种上海城市绿地植物中的积累和迁移特性,为筛选重金属富集能力强的植物,修复重金属污染土壤及相关研究提供参考。结果表明,研究区域内土壤重金属污染严重,Zn、Cu、Pb、Cd的平均含量分别为上海市背景水平最高值的12、5、20和62倍。而20种上海城市绿地植物重金属富集能力各不相同,其中杜鹃具有很强的富集Zn的能力,叶和茎中的Zn吸收量分别达到576和9 375mg/kg,而马唐对Cu和Cd均具有很强的富集能力。这些植物可作为工业区重金属污染修复植物的选择对象,具有进一步研究的价值。     

江汉平原稻田冠层CO2通量变化特征及其影响因素分析

二氧化碳（CO2）、甲烷（CH4）、氧化亚氮（N2O）被认为是最重要的温室气体,在气候变化中扮演着重要角色,实地测定稻田生态系统CO2通量是农业源温室气体监测与控制技术研究的基本内容。采用涡度相关法对江汉平原稻田生态系统进行了通量观测,并对水稻不同生长阶段冠层CO2通量、潜热、显热通量变化特征及其影响因素进行了分析。结果表明：水稻各生育期冠层CO2、潜热、显热通量日变化均表现出明显的单峰特征,但幅度不同,这与太阳总辐射的日变化及下垫面作物叶面积指数大小关系密切。稻田系统作物呼吸与土壤呼吸排放CO2,排放通量一方面与温度的变化有关,另一方面也受灌溉、作物生长状况的影响;稻田光合作用吸收同化大气CO2,吸收通量与作物群体叶面积指数大小、光合有效辐射强度有关。不同生长期冠层CO2通量与温度因子（气温、5cm土层温度）、光辐射强度因子（时光合有效辐射曝辐量）的相关性均达到极显著水平（P<0.01）,其中,分蘖-灌浆乳熟期CO2净通量对时光合有效辐射曝辐量响应的灵敏度较大,可以通过直角双曲线模型来拟合评估CO2净通量     

汉江中游河谷平原植被指数时空变化及其与沙化土地动态的关联关系

针对沙化土地广泛分布的汉江中游河谷平原区,采用MODIS EVI数据分析2003~2011年区域植被状态时空变化,并据此探讨沙化土地的动态特征。利用时序植被指数统计分析,探讨研究区植被的总体变化规律;分析不同缓冲区植被指数的空间分布格局,反映了区域环境状况的空间差异以及由此而可能产生的土地利用格局的变化;并基于不同距离缓冲区的EVI时空差异对比分析,探讨沙化土地动态与植被变化的关联关系。研究表明,近9 a来汉江中游河谷平原区EVI呈明显上升趋势;随着离河流距离的逐渐增加,每千米范围内各年的年均EVI值均表现出先增大后减小的空间特征,并在距河3 km区域处EVI值达到最大;而EVI的时空差异,则体现了沙化土地的空间分布与动态特征