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1.
为了解水污染治理后河道水生态环境改善情况,以许昌市清潩河为例,对治理前后河道5个点位表层沉积物中营养盐、重金属含量及沉积物氮释放量时空变化特征进行分析.结果表明:治理后,2017年5个点位的表层沉积物综合污染指数范围为7.69~15.25,均处于重污染状态,综合污染指数最低值为治理前2012年最高值4.87的1.6倍.各点位中重金属指标与2012年相比含量上升显著,Zn含量为2012年的12.44倍;而营养盐类指标含量下降明显,总氮及总磷平均含量仅分别为2012年的13.98%及5.68%.通过形态氮分析结果可知,离子可交换态氮的含量仅为2012年的6.73%,河道沉积物氮释放风险大大降低但沉积物中重金属污染更加严重.分析主要是清潩河上游长葛市涉及重金属排放的企业较多且在水污染治理中未得到有效控制.建议今后在对重污染河流实施综合治理时,应重视河道沉积物的污染状况评估.针对清潩河沉积物中重金属的污染状况,建议采取措施对重金属排放企业加强监管,并对河道沉积物中重金属污染进行治理和修复.  相似文献   

2.
植物修复重金属-有机物复合污染河道疏浚底泥的研究   总被引:2,自引:0,他引:2  
针对目前国内普遍存在的排污河道污染问题,通过盆栽试验研究了玉米、印度芥菜、超积累油菜、紫花苜蓿在施用不同配比的排污河道疏浚底泥上对重金属-有机物复合污染的修复情况及超积累的机理.结果表明,随着底泥配比的增加,植物发芽率的抑止程度也增加;适应底泥中高浓度复合污染的植物,底泥施用能促进其生长,提高植物体内的叶绿素含量.植物体内积累的重金属Zn、Pb、Cd以生长在底泥与土壤比为2:1的印度芥菜为最大,分别为1 521 mg/kg、453 mg/kg和11.7 mg/kg;Cu、Ni积累量以生长于底泥中的玉米为最大,分别为128 mg/kg和89.1 mg/kg.在本实验条件下,底泥中有机物以种植玉米的底泥为最大,为76.89%.通过环境扫描电子显微镜及配套的能谱分析发现,重金属在植物体内的聚集存在;经X荧光光谱仪和X射线衍射仪分析,确证了配合体之间及重金属和配合体相互形成架桥而聚集成团,形成重金属结合物积累在植物体内,且在植物根部发现积累了Cu的有机氯化物.种植前后底泥的X射线衍射对比表明,种植后重金属的晶格结构和存在形态发生了变化.  相似文献   

3.
以上海市某典型黑臭城市河道底泥为研究对象, 利用 6 种典型草本植物对 Cd-Zn-Cu 复合污染河道底泥进行了修复实验研究, 并考察了白三叶、高羊茅、黑麦草、披碱草、籽粒苋以及紫花苜蓿对底泥中重金属的耐受性、 富集转运特征和修复效果. 结果表明: 除白三叶外, 其余 5 种实验植物对底泥中的重金属均有良好的耐受性; 黑麦草对 Cd 和 Zn 的吸收能力较强, 其体内 Zn 含量高达 707.69 mg/kg; 披碱草对 Cu 的吸收能力较强; 除紫花苜蓿对 Zn 的积累外, 其余 5 种实验植物对重金属的积累主要在地下部分; 高羊茅和黑麦草对 Cd 与 Zn 的富集系数均大于 1, 且对 Cd、Zn 及 Cu 的提取效率分别在 7%、6% 及 2% 以上, 说明这 2 种实验植物对 Cd-Zn-Cu 复合污染河道底泥具有较大的修复潜力.  相似文献   

4.
长湖底质有机物富集现状及评价   总被引:6,自引:0,他引:6  
测定长湖底质有机质及总氮、总磷等指标,通过和其他富营养化湖泊的相关指标或当地环境本底值比较,评价长湖底质对湖水富营养化的潜在贡献,其结论是:有机质平均值为43.84 g/kg,含量丰富;总磷平均值为0.057%,含量较低,但在湖中各点差异明显;湖泊底质含氮量为0.234%,总体偏高;底质有机指数很高,湖泊处在严重的肥污染状态;有机质和营养盐主要来源于藻类等浮游生物;有机碳和总氮的相关性好,具有某种线形关系.  相似文献   

5.
以江苏太湖流域49个水生态功能分区为评估单元,通过综合污染指数法、地积累指数法以及潜在生态风险分析、多元聚类分析对沉积物中营养盐及重金属的污染状况进行调查和评估.结果 表明:流域沉积物中总氮(TN)均值为1171.14 mg/kg,各级区按TN含量由大到小排序为Ⅰ、Ⅱ、Ⅲ、Ⅳ级区;总磷(TP)均值为878.99 mg/...  相似文献   

6.
选取五源河上、中、下游底泥进行取样,系统分析底泥样品的物理参数、营养参数、有机 污染物和重金属。分析结果表明,底泥中有机质含量达到土壤三级标准,中游底泥样品有机质含 量最高(34.4 g/kg),底泥中有机磷和速效钾含量丰富达到土壤一级水平,但有效氮含量匮乏,仅达 到土壤五级水平,样品中未检出有机污染物。重金属污染采用潜在生态危害指数评价法进行评 价,评价结果表明测试底泥中Cd<8,RI<150,属于清洁水平。综合分析底泥物理参数、营养参数和 污染物水平,五源河上下游底泥可做建筑填土使用,中游底泥可做种植土壤利用,但应适当补充 氮肥。  相似文献   

7.
采取向河道中投加铁碳填料和反硝化菌复合包的方式,构建了铁碳微电解耦合反硝化菌曝气辅助原位削减河道黑臭底泥污染物及净化水质技术,模拟实验结果表明,当铁碳填料投加30g/kg、反硝化菌接种量15mg/kg、曝气量为60ml/min和曝气时间为9h/d的最佳组合下运行仅28d后,上覆水COD、NH4+-N、TN和TP去除率分别达85.7%、98.6%、65.7%和96.4%,稳定达到地表水Ⅳ类水标准;底泥TOC去除率达48.8%;底泥中BD-P和NaOH-P组分显著增加;底泥可转化态N含量显著减少;表层5~10cm底泥由深黑色变为浅褐色,耦合技术能快速削减河道黑臭底泥污染物及改善水质. 耦合体系中,铁碳微电解改善了水及底泥复杂有机物的可生化性,碳去除效能显著增强,N素的去除途径增多,P被吸附及生成沉淀固定到底泥中;投加的反硝化菌虽未成为优势菌种,但对脱氮有诱导作用;曝气提高了水体溶解氧,改善了底泥生境,激活了底泥土著微生物活性,三者协同作用削减黑臭底泥污染物并净化水质. 本研究为铁碳微电解耦合反硝化菌原位削减河道黑臭底泥污染物及净化水质技术提供理论依据.  相似文献   

8.
为调查安庆市区湖泊重金属污染状况,采集了安庆市区7个湖泊共22点的表层沉积物样品,分析了两种重金属As和Hg的含量分布。结果表明,As,Hg的含量范围分别为13.97~48.21 mg/kg和0.15~1.76mg/kg,均值含量分别为26.84mg/kg,0.58mg/kg。各市区湖泊不同程度的受到重金属As和Hg的污染。地累积指数法评价表明,市区湖泊普遍受到了Hg的轻度污染,而As的地累积指数普遍较低。生态风险评价表明,安庆市区湖泊潜在生态风险主要来自于Hg,东大湖、莲湖及菱湖处于中等的潜在生态风险状态,其他湖泊的潜在生态风险状态较低。  相似文献   

9.
利用原子吸收光谱法对山西师范大学三个校区内不同功能区表层土壤中的重金属含量进行测试分析,并采用单因子污染指数法和内梅罗污染指数法对其污染状况作出评价.结果表明,校园内土壤重金属Pb、Cr、Zn、Cu、Ni的平均含量分别为21.58 mg/kg、29.56 mg/kg、127.25 mg/kg、52.04 mg/kg、36.84 mg/kg,除Cr外其余均高于山西省土壤环境背景值,表明校园土壤中5种重金属元素都有不同程度的富集.单因子污染指数评价结果表明,仅三校区受到Cu元素的轻微污染,其余为未污染;综合污染指数评价结果表明,三个校区均未污染.  相似文献   

10.
以洱海全湖范围内的7条采样样线及上游3个主要湖泊的底泥为研究对象,测定了总氮、总磷2个参数,分析洱海沉积物的氮磷含量及其分布特性和影响因素。实验结果表明:洱海7条样线底泥中总磷的平均值达到266.80 mg/kg,极大值为818.20 mg/kg;总氮含量的平均值达到513.60 mg/kg,极大值为1 975.40 mg/kg。洱海上游3个主要湖泊底泥总氮、总磷含量实验测定结果为总氮的平均值为370.00 mg/kg,极大值为1 397.20 mg/kg;总磷的平均值为52.43 mg/kg,极大值为140.20 mg/kg。总氮、总磷含量与辐射乡镇的人口数量及耕地面积呈正相关,总氮含量还与年人均收入呈正相关。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
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