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1.
以富营养化底泥为研究对象,从环境微界面的角度出发,采用室内培养试验研究了常见沉水植物苦草对沉积物间隙水中As(Ⅲ)和As(Ⅴ)的迁移转化影响及环境微界面行为,并评估了苦草对沉积物-水界面中As的去除效果。试验结果表明:苦草增加了沉积物中溶解氧的渗透深度,降低了pH值、有机质(UV254)以及溶解态As、As(Ⅴ)、As(Ⅲ)、溶解态Fe(Ⅱ)和溶解态Mn的质量浓度;3种形态的As(溶解态As、As(Ⅴ)、As(Ⅲ))与溶解态Mn和UV254显著相关,与溶解态Fe(Ⅱ)相关性较差;苦草对As(Ⅲ)的去除效果(69.5%)优于其对As(Ⅴ)的去除效果(64.6%)。  相似文献   

2.
对长江口南翼上海滨岸带三个站点潮滩上覆水、沉积物和间隙水中的三态无机氮的含量分布的年度季节性监测研究表明:潮滩上覆水中溶解无机氮以NO3—N为主;表层沉积物中可交换态无机氮以NH4—N为主,约占70%-85%;沉积物间隙水中主要无机氮为NH4—N和NO3—N.在冬季潮滩上覆水中硝态氮含量明显降低,而沉积物和间隙水中氨氮和硝态氮的浓度则有较大增加.初步探讨了潮滩水和沉积物中无机氮分布季节性变化的主要影响因素,估算了潮滩表层沉积物—水界面无机氮的扩散通量,指出NIL—N的扩散释放对滨岸水环境质量影响较大.  相似文献   

3.
以成体铜锈环棱螺(Bellamya aeruginasa)为实验动物,探讨Cr~(6+)对其急性毒性及肝脏抗氧化指标的影响.结果表明,铜锈环棱螺对Cr~(6+)耐受性随时间延长而缓慢降低,Cr~(6+)对铜锈环棱螺的96 h的半致死和安全质量浓度分别为15.768 mg·L-1和1.577 mg·L-1,Cr~(6+)对铜锈环棱螺属低毒;铜锈环棱螺分别暴露于0.2,0.4,0.8 mg·L-1的Cr~(6+)水体,于胁迫后0,24,48,72,96 h采样分析.铜锈环棱螺肝脏中SOD活性敏感性最高,胁迫48 h后呈现显著性和极其显著性诱导,表明胁迫诱导抗氧化酶生成;对铜锈环棱螺肝脏中CAT活性的影响不明显,较低质量浓度Cr~(6+)只在48 h对肝脏中CAT活性有显著抑制作用;肝脏中GPx活性敏感性表现较弱,大多呈现抑制;GSH对Cr~(6+)胁迫比较敏感,在24 h时,GSH含量降低,72 h时0.8 mg·L-1质量浓度组铜锈环棱螺肝脏中GSH含量显著升高,对氧化胁迫作出相关应激反应.MDA含量在肝脏中低质量浓度组胁迫期间表现出显著性或极其显著性降低,高质量浓度组有极其显著性增高,脂质过氧化程度较高.铜锈环棱螺可作为Cr~(6+)污染监测的潜在指示生物.  相似文献   

4.
为揭示纳米材料原位覆盖对表层沉积物重金属的影响规律,开展室内培养原位沉积物柱试验,利用微界面分析技术、高分辨率平衡式间隙水采集技术(HR-Peeper)和薄膜扩散梯度技术(DGT),探究纳米Fe3O4原位覆盖对表层沉积物中Co、Ni释放的影响机制。试验结果表明:在纳米Fe3O4覆盖下沉积物pH值较对照组逐渐增大,Eh值先减小后增大;纳米Fe3O4覆盖可有效吸附间隙水中的溶解态Co和Ni,间隙水中的溶解态Co和Ni最大有效吸附率分别为27.07%及26.42%,有效影响深度分别为30 mm和10 mm;纳米Fe3O4覆盖有效抑制了沉积物中有效态Co和Ni向间隙水和上覆水扩散,沉积物中有效态Co和Ni含量分别降低了50.26%和15.31%。  相似文献   

5.
为了更好地控制和治理湖泊富营养化,探究沉积物-水界面中磷和铁的相关性特征。通过室内培养原位沉积柱,利用微界面分析技术和高分辨率平衡式间隙水采集技术(HR-Peeper),分3时段(加入摇蚊幼虫后的第7天、第21天和第35天),探究好氧环境中摇蚊幼虫扰动与铁的氧化耦合作用下沉积物-水界面体系中磷形态的迁移转化规律。研究结果表明:摇蚊幼虫扰动增加了沉积物中氧气的渗透深度和氧化还原电位E_h值,在第21天扰动最激烈;扰动降低了3个时段沉积物间隙水中的溶解态磷SRP(最大58%)、溶解态铁Soluble Fe(Ⅱ)(最大44%)的浓度;SRP与Soluble Fe(Ⅱ)在第7天和第21天也高度相关。可见,摇蚊幼虫的扰动作用所引起的沉积物中磷的变化受到了铁的氧化吸附控制。  相似文献   

6.
为探究不同吸附材料(锁磷剂和增氧剂)对沉积物内源污染物Co的影响机制,以太湖梅梁湾为研究区域,设计3组室内模拟试验(对照组、增氧剂组及锁磷剂组),基于高分辨率平衡式间隙水采样(HR-Peeper)装置采集4个阶段(加入吸附材料后的第4天、30天、90天、150天)水样,解析原位覆盖条件下沉积物剖面溶解态Co、Fe(Ⅱ)、Mn的垂向分布特征及相互作用机制。结果表明:锁磷剂和增氧剂未造成水体中的pH值和Eh值的剧烈变化;沉积物剖面中溶解态Co质量浓度降低了1.29%~45.87%,且30d时的吸附效果最好;增氧剂组及锁磷剂组沉积物水界面Co释放通量较对照组分别降低了1.00μg/(m2·d)和1.19μg/(m2·d);沉积物剖面Co的释放受铁、锰的氧化还原控制,且主要受锰的氧化还原控制;增氧剂对钴的吸附效果优于锁磷剂,且有效吸附时间更久。  相似文献   

7.
以铜锈环棱螺为受试生物,采用半静态法研究了不同浓度的Cu2+、Zn2+复合污染对铜锈环棱螺肝胰腺SOD和CAT酶活性的影响.结果表明:单一Cu2+(1.0 mg·L-1)或Zn2+(2.0 mg·L-1)不会引起铜锈环棱螺死亡,但大多数Cu2+、Zn2+复合污染会引起铜锈环棱螺死亡.单一Cu2+(0.1 mg·L-1)或Zn2+(1.0 mg·L-1)处理时,铜锈环棱螺SOD和CAT酶活性均出现先增后降现象,而且绝大部分酶活性大于对照组.0.1 mg·L-1Cu2+与2 mg·L-1Zn2+复合污染时,铜锈环棱螺CAT酶活性均低于对照组,并且均达差异极显著水平(P0.01或P0.001).所有0.1 mg·L-1Cu2+与2 mg·L-1Zn2+复合污染组铜锈环棱螺SOD酶活性却都高于对照组,而且差异均不显著(P0.05).所有1.0 mg·L-1Zn2+与不同浓度Cu2+复合污染组铜锈环棱螺的SOD和CAT酶活性均比单一Zn2+处理组低.  相似文献   

8.
黄浦江上游大型底栖动物生物多样性现状   总被引:3,自引:0,他引:3  
2005年4月至2006年3月对黄浦江上游大型底栖动物群落结构进行了调查.采用香农威纳指数(H′)、物种均匀度指数(J)和物种丰富度指数(D)对黄浦江上游大型底栖动物的群落结构、种类组成、多样性进行了分析.本次调查共采到底栖动物13种.密度优势种为环节动物门的霍甫水丝蚓(Limnodrilus hoffmeisteri)、软体动物门的铜锈环棱螺(Bellamya aeruginosa)以及河蚬(Corbicula fluminea).生物量优势种为软体动物门的铜锈环棱螺以及河蚬.淀峰断面的香农威纳指数(H′)、物种均匀度指数(J)和物种丰富度指数(D)都高于松浦大桥.季节变化方面,三种指数的最高值都出现在秋季,最低值则分别出现在夏季、冬季和春季.生物多样性除了受种的数量及其个体密度影响外,还与多种因素有关,如水温、水质、底栖环境和人为干扰等.  相似文献   

9.
在模拟磷酸盐在沉积物-水界面的交换研究中对相关的环境因子进行了动态监测与相关分析。通过根际土壤溶液采样器等工具连续监测溶解氧(DO)、电导率(Cond)、pH、氧化还原电位(ORP)等参数在模拟系统中上覆水及沉积物的不同层次的动态,并分析了各参数在各层间的相互关系以及相互影响作用。结果表明:上覆水底层DO浓度显著低于中上层;上覆水各层电导率没有显著差异且随时间线性上升;pH动态具有显著的空间差异性,界面位置是pH的突变点,上覆水pH的变化滞后于间隙水;沉积物ORP低于上覆水,界面是突变点。沉积物上层和上覆水与DO各层ORP呈正相关,但与底层间隙水ORP无关,其他参数间的相互作用不明显。  相似文献   

10.
利用高分辨率的薄膜扩散梯度技术(Diffusive Gradients in Thin Films,DGT)和微电极技术,从微界面的角度研究了摇蚊扰动对沉积物中溶解氧(DO)、活性磷(Labile P)、活性铁(Labile Fe)及Labile P扩散通量的影响。研究发现摇蚊幼虫扰动增加了沉积物中溶解氧的渗透深度,降低了Labile P和Labile Fe的浓度,同时抑制了Labile P向上覆水中的释放。由于Labile P与Labile Fe显著相关(对照组R=0.672,P0.001;摇蚊组R=0.810,P0.001),可知Labile P的变化受DO和Labile Fe控制,即Labile Fe被氧化生成三价Fe(OOH),同时吸附Labile P,使得Labile P和Labile Fe同时降低。  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 Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
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   

15.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

16.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

17.
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   

18.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

19.
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   

20.
赵英华 《科技信息》2008,(12):219-220
0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation's behavior in their social life throughout the long history is beyond list.  相似文献   

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