Study of Fractionation and Potential Mobility of Metal from the Guadalquivir Estuary: Changes in Mobility with Time and Influence of the Aznalcollar Mining Spill

This study analyzed the evolution of metal levels in surface sediments from the Guadalquivir estuary between 1997 and 2002 and assessed the impact of the April 1998 Aznalcollar tailings dam failure and subsequent cleanup on metal concentrations in surface sediments. We also analyzed metal distribution with time in five chemical fractions of the surface sediments: exchangable, carbonate, reducible, oxidizable, and residual. This work showed that the April 1998 Aznalcollar tailings dam failure caused a considerable increase in the concentrations of Cd, Zn, Cu, and Pb in the surface sediments of the Guadalquivir estuary. It was also found there was a change in the distribution of Cd, Zn, Cu, and Pb between the chemical fractions of the sediment after the failure of the dam. There were increases in the percentages of Cd in the carbonate fraction, of Zn and Pb in the reducible fraction, and of Cu in the oxidizable fraction, whereas the percentages of these elements associated with the residual fraction decreased. In 1999, there was a decrease in the metal concentrations in the surface sediments from the Guadalquivir estuary, and by 2000 the chemical distribution and metal levels had returned to levels similar those before the dam failure.     

Impacts of home shopping on vehicle operations and greenhouse gas emissions: multi-year regional study

As a shopping behavior trend, home shopping has become more popular. This shopping method seems to decrease shopping trips, yet more delivery trucks are required to be on the roads. In addition, even more personal trips may occur because saving time on shopping might allow more time for alternate activities. A study investigated the effects of home shopping on vehicle operations and greenhouse gas emissions. The purpose of that study was to identify the home-shopping impacts on transportation system, its net effects on traffic volume of the transportation network, its effects associated with environmental sustainability and then to provide some projections for future condition. Simulation results showed that home shopping will put additional burden on Newark transportation network, as identified through four measures of effectiveness (MOEs) which were travel time, delay, average speed and greenhouse gas (GHG) emissions.     

Supply chain and logistics competencies in humanitarian aid

The continuing incidence of disasters and their associated challenges has increased the demand for humanitarian logisticians. However, there is a dearth of research on their essential competencies. This paper proposes, therefore, a humanitarian logistics competency framework (HlCF) to assist with the professional development of humanitarian logisticians. In creating the HlCF, nine competency domains containing 29 specific competencies across four levels (entry to senior management) were identified. This study makes two key contributions to the literature: (i) it extends the discussion of competency frameworks in humanitarian logistics; and (ii) it presents a framework designed to support the human resource plans and practices of aid agencies. The HlCF allows not only individual humanitarian logisticians to develop the competencies necessary for career success, but also humanitarian organisations to map their own competency frameworks to a common standard. This will, in turn, facilitate workforce mobility and support the overall concept of a certified humanitarian logistics professional.     

流动性视角下乡村旅游地游客地方感差异分析

基于流动性理论,以400份北京居民的调查问卷为样本,分析了乡村旅游者流动中的地方感差异,从游客地方感角度为流动市场中的乡村发展寻找途径。结果表明:不同游客群体间存在明显的地方感差异,且地方感知(自然维度、人文维度、服务感知)对地方情感(地方依恋、地方忠诚)存在显著影响,地方情感对重构乡村地方、延续乡村性具有重要意义。基于研究结论,建立乡村旅游者地方感研究模型。     

Chemical fractionation of metals in core sediments of Orogodo River,southern Nigeria

Sequential chemical extraction of metals (Cu, Ni, Mn, Fe, Pb, Cr, and Zn) from core sediments of the Orogodo River was carried out with a view of providing information on the phase distribution of these metals with respect to depths and seasons. The results indicate that copper was speciated into organic matter/sulfide, Fe–Mn oxides, and residual forms at 0–5?cm depth while at deeper sections copper was predominantly in the residual form. Nickel was speciated mainly into Fe–Mn oxides and residual forms. The average of lead in various particulate phases of the sediment are 0–100% for residual; 0–8% for carbonate; 0–16.2% for exchangeable; 0–10% for organic matter/sulfide form and 22–56% for Fe–Mn oxides bound metals. Manganese was speciated into exchangeable (10–36%) and Fe–Mn oxides bound (10–48%) at the surface layers of 0–20?cm depths and predominantly in the residual form in deeper sections implying partitioning into trioctahydral clay and/or well-defined crystalline oxides. Iron was predominantly in the Fe–Mn oxides and residual fractions, less than 8% in the organic fraction, and 24.4–37.3% in the exchangeable and carbonates fractions at the surface. The percentage contributions of iron in the exchangeable and carbonate fractions decreased to 3.2% at 55–60?cm depth. The amount of chromium in the exchangeable fraction ranged from 0% to 7% for exchangeable; 0–26.5% for organic matter/sulfide bound; 3.8–17.9% for Fe–Mn oxides; and 46.8–100% for residual fraction. The mobility factors of the metals indicated that these metals were relatively mobile at top sections as compared with deeper sections. The overall picture of metal mobility and availability indicates potential contamination risk by Fe, Zn, Mn, and Pb in the Orogodo River sediment system.     

Mobilities and teachabilities of heavy metals in sludge with humus soil

Chemical forms of Zn, Ni, Cu, and Pb in municipal sewage sludge were investigated by adding humus soil to sludge and by performing sequential extraction procedures. In the final sludge mixtures, Zn and Ni were mainly found in Fe/Mn oxide-bound (F3) and organic matter/sulfide-bound (F4) forms. For Zn, exchangeable (F1), carbonate-bound (F2), and F3 forms were transformed to F4 and residual forms (F5). For Ni, Fl and F2 forms were transformed to Fl, F2, and F3 forms. Both Cu and Pb were strongly associated with the stable forms F4 and F5. For Cu, F2 and F3 forms were major contributors, while for Pb, F3 and F4 forms were major contributors to F5. Humus soil dosage and pH conditions in the sludge were strongly correlated with the forms of heavy metals. Five forms were used to evaluate metal mobilities in the initial and final sludge mixtures. The mobilities of the four heavy metals studied decreased after 28 days. The metal mobilities in the final sludge mixtures were ranked in the following order: Ni > Zn > Cu = Pb. Leaching tests showed that the mobilities of Zn and Ni in lower pH conditions (pH 4) were higher than those in higher pH conditions (pH 8).     

丙溴磷在土壤中的吸附与迁移行为研究

采用气相色谱(GC-FPD)法建立了丙溴磷在水和土壤中的残留分析方法。结果表明,丙溴磷在水和土壤中的平均回收率在87.18%~103.64%之间,变异系数为4.84%~9.89%;丙溴磷在水和土壤中的最低检测浓度分别为0.005 mg/L,0.05 mg/kg。采用平衡吸附法和薄层层析法研究了丙溴磷在砂土、壤土和粘土中的吸附和迁移特性。结果表明:丙溴磷在砂土、壤土和粘土中的吸附常数Kd分别为12.70、33.65和74.92,土壤对丙溴磷的吸附能力与土壤有机质含量呈正相关,其移动性分别表现为在砂土、壤土中不易移动,在粘土中不移动。     

餐厨降解菌的生物特性研究

为了研究餐厨降解菌的生物特性,选取耐盐性、基质迁移性及其在餐厨降解中的酶活特性展开研究,以此来揭示各菌种在降解过程中的优势特性及其各自发挥的作用.结果表明,混合菌产酶优于单菌种;菌株在2.5%NaCl浓度下可正常生长,耐盐性排序为:博德特氏菌(Bordetella petrii)汉氏硝化细菌(Nitrobacter hamburgensis)螺旋巴克斯霉(Backusella circina),迁移性排序为:博德特氏菌(Bordetella petrii)汉氏硝化细菌(Nitrobacter hamburgensis)螺旋巴克斯霉(Backusella circina).综合来看,博德特氏菌在降解前期作用明显,蔗糖酶活后期保持稳定表明堆肥矿质化趋于稳定,脱氢酶和多酚氧化酶活在后期逐步降低并趋于稳定表明堆肥腐熟性良好且稳定.     

Two ways of defining sustainable mobility: Autolib’ and BeMobility

Abstract

European cities have emerged as laboratories for ‘sustainable mobility'. In the last few years, they have supported numerous electric car projects which combine clean engine technologies with offers on public or shared mobility. This paper compares two ongoing public electric car services in Berlin (BeMobility) and Paris (Autolib’). We explain how both projects shape future visions of sustainable mobility and transform regional transport systems in specific ways through their performative impact as local transport policy tools. Focusing on the socio-economic and political processes through which both projects were conceived and put into practice, we explain their differences as they reflect participating actors' interests in a French versus German industrial and transport policy context after the economic crisis in 2008. We find that whereas BeMobility integrates electric cars as one element in Berlin's intermodal transport system, and thus is centred around ‘intermodality' as the central vision of sustainable transport, Autolib’ in Paris essentially reproduces the dominant mode of private passenger car transport through adding a shared electric car fleet.     

连续施用污泥堆肥土壤剖面中重金属积累迁移特征及对小麦吸收重金属的影响

通过大田试验,定量研究连续施用污泥堆肥后土壤剖面中不同重金属积累迁移和对小麦吸收重金属的影响,为科学确定农田土壤重金属环境容量和农田土壤重金属污染防控提供依据.结果表明,连续4 a施用污泥堆肥农田耕层土壤(0~15cm)中Cu、Zn含量随污泥施用时间和施用量增加而显著增加,污泥施用带入的Cu、Zn在耕层土壤中积累率最高分别可达到75.3%和85.9%;污泥施用量较高时,Cu、Zn向土壤深层迁移,本试验条件下Cu可迁移至15~30 cm土层,Zn可迁移至60~90 cm土层;连续施用污泥堆肥4 a后,0~15 cm土层中Cd、Pb含量显著增加,与对照相比增幅分别是57.2%~165.2%、13%~34%,60~90 cm土层中Cr、As、Pb含量也显著高于对照;连续施用污泥堆肥小麦籽粒中Zn含量显著增加,增幅为13.3%~47.9%.部分污泥处理小麦籽粒中的Cr、Pb含量超出国家食品卫生标准(GB 2762-2012);4 a小麦收获对各重金属累计携出率均低于10%,小麦籽粒对Cu、Zn的累计携出量大于秸秆,而对Cr、As、Cd、Pb的累计携出量小于秸秆.随污泥施用量的增加,小麦收获对各重金属累计携出率降低.确定农田土壤重金属环境容量时要考虑重金属在土壤剖面中的向下迁移量.