亚热带水库沉积物钻孔中有机质的历史记录及其环境意义

氢指数(HI)是重要的有机质评价参数,能够反映沉积有机质中脂肪大分子物质的相对含量,并用于反演水生生态系统的历史初级生产力,有助于研究藻类生产力对污染物的富集作用。为了探讨氢指数的环境指示作用,选择了亚热带的3座水库作为研究对象,采用Rock-Eval热解与生物标志物-中性糖方法相结合的研究技术,研究了沉积钻孔有机质的来源与特征;并结合210Pb和137Cs定年技术,综合运用氢指数和总糖含量对水库的初级生产力进行了重建。结果表明:中富营养的增塘和联安水库沉积有机质主要来源于浮游藻类,且受降解的程度较小,而贫营养的新丰江水库钻孔下层有机质主要是受降解作用或陆源高等植物等的影响。近年来,3个水库的HI值都有显著性的增加,且与其对应的总糖含量以及近50年来的滑动平均温度都高度的相关,说明这些水库都经历了气候变暖所引起的初级生产力增长。同时,升高的水库生产力扩大了沉积物剖面中重金属和多环芳烃的累积。     

象山港大型底栖生态状况的多指数互校法评价与分析

2011年在象山港设置31个调查站位,分别于夏季和冬季开展了大型底栖动物调查,同时分析了表层沉积物质量。分别采用ABC曲线法、AMBI指数法和M-AMBI指数法对象山港大型底栖生态健康状况进行分析评价,并结合沉积物质量评价结果,对3种方法评价结果进行相互校正,得出象山港大型底栖生态现状综合评价结果。结果显示,2011年夏季象山港67.7%的调查站位底栖生态被评为良,32.3%的调查站位被评为中;冬季3.2%站位评为优,45.2%的站位被评为良,45.2%的站位被评为中,6.4%的站位被评为差。M-AMBI,AMBI和ABC 3种方法的评价结果显著相关,ABC法评价结果与沉积物中石油类和硫化物含量显著相关,AMBI指数与沉积物中TOC含量显著相关,M-AMBI指数与沉积物中重金属Hg含量显著相关。     

加速溶剂萃取(ASE)-固相萃取(SPE)-高效液相色谱法(HPLC)测定土壤中青霉素钠

建立了一种加速溶剂萃取(ASE)-固相萃取(SPE)-高效液相色谱(HPLC)测定土壤中青霉素钠的简单、快速的方法.样品以超纯水为提取溶剂,50℃提取温度为ASE提取条件参数;HLB型固相萃取柱富集净化:6.0mL 5%甲醇淋洗、4.0mL乙腈-甲醇(1∶1)洗脱;高效液相色谱-紫外检测器(HPLC-PDA)测定,检测波长λ=191.1nm,柱温30℃,流动相为乙腈-0.1%甲酸/水(1∶1),采用等梯度洗脱程序,取得较好的检测分离效果.对0.5、2.0、8.0mg·kg-1等3个不同添加浓度水平的青霉素钠平均加标回收率范围为73.1%—89.7%,回收率相对标准偏差RSD范围为1.1%—2.9%(n=5),检出限可达235.0μg·L-1.结果表明,该方法操作简单,快速,准确度和精密度均符合质量控制要求,能够满足环境土壤样本中痕量青霉素钠检测分析的要求.     

热闷钢渣用单轨移动罩车的设计

根据钢渣热闷工艺要求进行单轨移动罩车的结构设计与行走装置的设计,通过三维建模软件及理论力学分析计算此罩车的配重及质心,使罩车与导向装置接触处的压力最小,且罩车施加给低地轨的横向静摩擦力最小。通过此方法设计的单轨移动罩车能大大改善钢渣热闷厂房的工作环境,减少厂房的腐蚀,提高厂房屋顶的寿命周期。     

珍贵树种土沉香生长环境的土壤特性与营养特性分析

对我国野生土沉香4个主要分布区的土壤特性及自身营养特性进行了分析研究。结果表明,不同分布区的同一土层的土壤物理性质有明显的差异（P〈0.05）。海南临高分布区各层土壤容重最小,总空隙度、自然含水量毛管持水量比较高;海南屯昌分布区各层的土壤容重最大,总空隙度较低;广东东莞分布区与广东陆河分布区各层土壤松紧度比较适宜,透水性,通气性,持水能力比较协调。各分布区土壤均呈酸性,其有机质含量和营养元素含量偏低。土壤有效Mn、有效B均处于较低水平,有效Fe的含量均高于临界值;海南屯昌分布区土壤中有效Cu的含量极低,其余3分布区则均高于临界值;除海南临高分布区有效Zn的含量高于临界值,其他3个分布区均低于临界值;海南屯昌分布区土壤有效S含量稍低于临界值,为中等水平,广东陆河分布区高于临界值处于较高水平,广东东莞分布区为临界值的2.76倍,而海南临高分布区则高达临界值的7.31倍,均处于极高水平。野生土沉香叶片各营养元素之间的相关性总体不明显。     

Competitive adsorption and desorption of copper and lead in some soil of North China

The competitive adsorption and desorption of Pb(II) and Cu(II) ions in the soil of three sites in North China were investigated using single and binary metal solutions with 0.01 mol·L^-1 CaCl₂ as background electrolyte. The desorption isotherms of Pb(II) and Cu(II) were similar to the adsorption isotherms, which can be fitted well by Freundlich equation (R₂>0.96). The soil in the three sites had greater sorption capacities for Pb(II) than Cu(II), which was affected strongly by the soil characteristics. In the binary metal solution containing 1∶1 molar ratio of Pb(II) and Cu(II), the total amount of Pb(II) and Cu(II) adsorption was affected by the simultaneous presence of the two metal ions, indicating the existence of adsorption competition between the two metal ions. Fourier transform infrared (FT-IR) spectroscopy was used to investigate the interaction between soil and metal ions, and the results revealed that the carboxyl and hydroxyl groups in the soil were the main binding sites of metal ions.     

Seed terminal velocity, wind turbulence, and demography drive the spread of an invasive tree in an analytical model

Little is known about the relative importance of mechanistic drivers of plant spread, particularly when long-distance dispersal (LDD) events occur. Most methods to date approach LDD phenomenologically, and all mechanistic models, with one exception, have been implemented through simulation. Furthermore, the few recent mechanistically derived spread models have examined the relative role of different dispersal parameters using simulations, and a formal analytical approach has not yet been implemented. Here we incorporate an analytical mechanistic wind dispersal model (WALD) into a demographic matrix model within an analytical integrodifference equation spread model. We carry out analytical perturbation analysis on the combined model to determine the relative effects of dispersal and demographic traits and wind statistics on the spread of an invasive tree. Models are parameterized using data collected in situ and tested using independent data on historical spread. Predicted spread rates and direction match well the two historical phases of observed spread. Seed terminal velocity has the greatest potential influence on spread rate, and three wind properties (turbulence coefficient, mean horizontal wind speed, and standard deviation of vertical wind speed) are also important. Fecundity has marginal importance for spread rate, but juvenile survival and establishment are consistently important. This coupled empirical/theoretical framework enables prediction of plant spread rate and direction using fundamental dispersal and demographic parameters and identifies the traits and environmental conditions that facilitate spread. The development of an analytical perturbation analysis for a mechanistic spread model will enable multispecies comparative studies to be easily implemented in the future.     

美国饮用水水源地保护经验及其对我国的启示

新冠肺炎疫情对公众健康造成了极大威胁。针对疫情可能造成的水污染问题,各地生态环境部门均全力加强城市和农村饮用水水源地水质监测预警工作,突出了当前形势下饮用水水源保护工作的重要性。为实现安全饮用水目标,美国在法制体系、组织结构、饮用水水源地风险评估和保护计划等方面积累了丰富的经验,为我国应对疫情、实现饮用水安全保障提供了诸多启示。美国实践经验表明,饮用水水源地保护应建立从废水排放控制到水源地风险防范的全方位、一体化管理体系;完善"从水源地到水龙头"的监测与应急体系;构建分工明确、权责清晰的制度体系;完善公众参与和信息公开,形成多方共治的良好局面。基于美国水源地保护经验,本文研究提出如下建议:加强全国饮用水水源地风险评估,严防医疗污水和城镇生活污水向水源地排放;加强水源地水质监测和预警,提升监测预警水平并制定备用水源等应急响应计划;强化地方政府对水源地的统一监管职能,明确水源地管理部门和水源地水厂的职责分工,加强组织协调和联防联控;完善公众参与和信息公开,增强公众环保意识和"主人翁"意识。     

我国沿海地区港口竞争力综合评价

港口是连接世界生产、分配、交换和消费的中心环节.随着世界经济及国际贸易的快速发展,港口在一国区域经济和对外贸易中的地位日益突出,港口之间竞争日益加剧,因此对港口竞争力的研究意义重大.将熵权法与TOPSIS法相结合,对我国沿海地区的港口竞争力进行综合评价和比较分析.结果表明,广东、浙江、上海、山东港口竞争力普遍较强,辽宁、福建、江苏、天津港口竞争力中等,河北、海南、广西港口竞争力相对较弱,提出了相应的对策建议.     

Perverse Incentive Structure and Policy Implementation Gap in China's Local Environmental Politics

The obvious paradox within China's environmental politics is the big gap between the central government's policy and its implementation outcomes at local levels. Despite concerns about implementation at the local level, much about the role of central governments in China's local environmental politics is still poorly understood. This article examines how the incentive structure set by the central authorities affects the policy implementation gap at the local level. Drawing on fieldwork and document analysis, this article argues that the incentives set by the central government regarding environmental policy implementation at local levels are perversely structured, meaning that the central government provides much more incentive for local governments' non-implementation or poor implementation of its environmental policies than it provides for full implementation. The central government's failure to encourage—politically, financially, as well as morally—local government officials to appropriately implement environmental policies can partly explain the production of the policy implementation gap at the local level. This implementation gap cannot be overcome by efforts at the local level unless the central government takes significant measures to address the perverse incentive structure embedded in the overall structure of China's local environmental politics.