Can PAHs influence Cu accumulation by salt marsh plants?     

Almeida CM  Mucha AP  Delgado MF  Caçador MI  Bordalo AA  Vasconcelos MT 《Marine environmental research》2008,66(3):311-318

The presence of polycyclic aromatic hydrocarbons (PAHs) may change the mechanisms of metal uptake, thus influencing kinetics and extent of metal phytoextraction. Studies on the subject are scarce, particularly for salt marsh plants. The aim of this work was to investigate the effect of PAHs on the uptake of Cu by Halimione portulacoides, a plant commonly found in salt marshes. Experiments were carried out in the laboratory, either in hydroponics (sediment elutriate) or in sediment soaked in elutriate, which were prepared with sediment and water from a salt marsh of the Cavado river estuary (NW Portugal). Groups of H. portulacoides (grown in a greenhouse) were exposed to those media during six days. Cu(2+) (as Cu(NO(3))(2)), 10(2) and 10(4)mugl(-1), was added to the media as well as 1.6mugl(-1) of the sixteen EPA priority PAHs (0.1mugl(-1) of each PAHs). Cu was assayed in solutions, sediments and different plant tissues before and after experiments. After exposure, photosynthetic efficiency and levels of chlorophylls were also measured, indicating that plant stress indicators were identical in all plants independently of the media to which the plants were exposed. PAHs influenced both the soluble Cu fraction and Cu uptake by plants. The amounts of metal accumulated in both roots and stems were significantly higher when the 10(4)mugl(-1) of Cu enriched elutriate was amended with PAHs. Thus, results suggest that PAHs may modify Cu solubility, the Cu sorption by plants and/or the passive penetration of Cu into the root cells. Therefore, the combined effects of different types of pollutants should be taken in consideration when studying the remediation potential of plants, namely in terms of phytoextraction.  相似文献   

东北地区城际高铁网络格局特征与演变趋势     

初楠臣  张平宇  李鹤  姜博 《地理科学》2019,39(5):761-769

构建城际高铁联系强度模型并结合社会网络分析探讨东北地区高铁网络格局特征与演变趋势,研究结果表明：① 东北地区高铁网络整体关联性相对紧密,小世界效应显著,但仍处于弱连接状态,涵盖长春-四平-沈阳-铁岭-抚顺、大连-辽阳-鞍山-营口-盘锦、松原-白城-乌兰浩特子群,吉林-延吉、齐齐哈尔-大庆、丹东-本溪、锦州-葫芦岛关系对,7片区组织格局成型;② 以哈尔滨为分界线的东南部比西北部的高铁通达联系密切,高铁要素集散呈“一核心、三边缘”格局特征,长春为东北高铁中介运输轴点;③ 辽、吉省内高铁联系紧密,黑、蒙东松散,辽宁省呈沈阳-大连一轴、沈阳-锦州与沈阳-丹东两翼格局,吉林省呈长春-吉林-四平与长春-吉林-延吉三角交叉状格局,黑龙江省呈哈尔滨-大庆-齐齐哈尔轴线状格局,蒙东区呈乌兰浩特孤立化格局;④ 东北地区高铁的运营加快了哈大齐、哈长与长吉图一体化进程,有助于构建辽中南内部哈大、沈丹与丹大高铁三角骨架,同时应依托7片区与4大中俄朝韩主通道搭建东北内外、海陆统筹的铁路网络架构。  相似文献   

DEM坡度计算的适宜窗口分析   总被引：5，自引：0，他引：5  

刘学军  张平  朱莹 《测绘学报》2009,38(3)

局部分析窗口大小是DEM坡度计算的关键因素之一.首先建立不同分析窗口下的坡度精度模型,讨论拟合曲面和DEM地形曲面匹配程度的分析方法,然后以分布在不同地貌类型和地形特征部位的样点为研究对象,分析不同窗口大小对坡度计算的影响规律;通过X2检验法,研究不同分析窗口下拟合曲面和DEM曲面的匹配程度,最后综合考虑两个方面的影响,探讨基于DEM坡度计算的适宜窗口.研究主要结论为:①坡度计算精度随着分析窗口的增大而提高;②随着分析窗口的增大,拟合曲面与DEM地形曲面之间匹配性逐步减弱;③坡度计算的精度应该在拟合曲面和DEM地形曲面相匹配的前提下,通过适当扩大局部窗口来获得,推荐5×5局部分析窗口为DEM坡度计算的适宜窗口;④DEM地形参数计算中,不应过分的追求计算精度而忽视形态的相似性,否则尽管地形参数的精度很高,但只具备数学意义而没有地形意义.  相似文献   

地质管材抗外挤问题的探讨          下载免费PDF全文

张平占 《探矿工程》1994,(6):21-23

系统地探讨了地质管材的抗外挤问题及抗挤强度的计算，并列出了一系列计算表格，供野外队参考使用。  相似文献   

不列颠哥伦比亚Kemess Creek地区应用多科学技术进行的综合勘查项目…     

Rebg.  CM  邹光华 《物探化探译丛》1994,(2):44-46

  相似文献   

长坡锡矿床成矿规律与隐伏矿体的找矿勘探   总被引：4，自引：1，他引：4  

张平 《地质与勘探》1983,(3)

大厂矿田是我国的重要锡矿基地之一.长坡矿区是大厂矿田的主要矿床,分布面积大于1平方公里,是一个以锡为主并伴生铅、锌、锑、硫、砷、铟、锡、镓、银等的大型锡石-硫化物矿床. 矿山生产30年来,我们在上部采区进行矿床地质研究,探索成矿规律,预测隐伏矿体,获得了  相似文献   

超稠油油藏转小井距蒸汽驱条件及时机   总被引：3，自引：3，他引：0  

李彦平  张平  揣金海  李华  孙鹏 《西北地质》2003,36(4):74-78

蒸汽驱是稠油油藏经过蒸汽吞吐开采后进一步提高原油采收率的主要热采阶段。但不是说任何时候转驱都可取得较好的效果。笔者系统研究了影响蒸汽驱开采效果的因素：原油粘度、油层有效厚度、纯总厚度比、起始含油饱和度和油层非均质性等,确定出适宜蒸汽驱开采的油藏条件。在分析稠油油藏加密吞吐后油藏条件变化的基础上．利用油藏工程数值模拟技术研究确定出超稠油油藏转小井距蒸汽驱的合理时机。  相似文献   

磁变仪标定电路设计与实现     

段建新  张平  张志敏 《地震研究》2004,27(Z1):81-83

研制了地磁台磁变仪标定器.该标定器采用集成电路,使标定过程完全呈线性变化,标定程序简单易操作,从而极大地提高了标定电流的稳定性及整个标定质量.  相似文献   

振兴锦州经济的对策思考     

张平 《中国地名》2006,(8)

“十一五”期间是我国经济周期发展的上升阶段,全国不仅呈现了东部大发展,西部大开发,中部大调整,东北大振兴的全面均衡的发展格局,而且各地区之间互动发展的趋势逐步显现,在竞争中合作,在合作中发展,在发展中创新已经成为国内、乃至国际促进区域经济发展的重大战略之一。本文在对锦州经济调查的基础上提出以下问题的思考及对策。一、锦州经济发展面临的机遇与挑战“十一五”期间,锦州迎来了难得的机遇。从全国来看,中央将东北作为新经济区域中的重要组成部分,在政策和产业布局上为我们提供了一个更大更高的发展平台。二十世纪九十年代初,省…  相似文献   

The effect of an oil drilling operation on the trace metal concentrations in offshore bottom sediments of the Campos Basin oil field,SE Brazil     

Rezende CE  Lacerda LD  Ovalle AR  Souza CM  Gobo AA  Santos DO 《Marine pollution bulletin》2002,44(7):680-684

The concentrations of Al, Fe, Mn, Zn, Cu, Pb, Ni, Cr, Ba, V, Sn and As in offshore bottom sediments from the Bacia de Campos oil field, SE Brazil, were measured at the beginning and at 7 months after completion of the drilling operation. Concentrations of Al, Fe, Ba, Cr, Ni and Zn were significantly higher closer to the drilling site compared to stations far from the site. Average concentrations of Al, Cu, and in particular of Ni, were significantly higher at the end of the drilling operation than at the beginning. Comparison between drilling area sediments with control sediments of the continental platform, however, showed no significant difference in trace metal concentrations. Under the operation conditions of this drilling event, the results show that while changes in some trace metal concentrations do occur during drilling operations, they are not significantly large to be distinguished from natural variability of the local background concentrations.  相似文献