Hydrochemical characteristics and seasonal variations in groundwater quality of an alluvial aquifer in parts of Central Ganga Plain,Western Uttar Pradesh,India

The present study was undertaken to assess major ion chemistry of groundwater in parts of the Central Ganga Plain and observe seasonal variations in its chemical quality. Systematic sampling was carried out during November 2005 and June 2006. The major ion chemistry of groundwater shows large variations, so much so that at times the meteoric signature seems to be completely obliterated. In many samples the concentrations of SO₄, NO₃ and F are above the permissible limit for human consumption. The graphical treatment of major ion chemistry helps in identifying four types of groundwater. All possible ionic species such as NaCl, KCl, NaHCO₃, NaSO₄, KNO₃, NaNO₃, CaHCO₃, MgHCO₃, MgSO₄ are likely to occur in groundwater system. The observed chemical variations may be attributed to sediment water interaction, ion exchange, dissolution mechanisms and anthropogenic influences such as application of fertilizers and effluents from sugar factories and paper mills. A general increase in TDS is observed in samples during June 2006. The increase in salinity is attributed to evaporation from water table, irrigation return flows, anthropogenic activities and below average rainfall in 2005 and 2006. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

浅析江西省龙南塔背风化壳型锆铪矿床地质特征

对龙南县塔背矿区锆铪矿床地质特征进行了归纳总结,为今后在赣南花岗岩区开展此类型找矿工作指出了找矿标志。     

陕北能源化工基地地下水开发利用现状及影响研究

通过分析陕北能源化工基地地下水资源分布、利用现状、利用量的动态变化以及能源化工基地建设对地下水的影响,表明陕北能源化工基地地下水的开发是有限度的;从其供水结构和利用结构来看,工业用水的比例较低;从地下水用水的空间分布来看,与能源资源的空间分布和开发利用的空间分布一致。能源资源的开发利用不仅大量消耗地下水,还会对地下水系统产生破坏作用,同时还对地下水造成严重污染。随着基地建设进程的推进,对水资源的需求日益加强,必须要通过调整用水结构、节水、开源、保护和治污等措施的综合实施,达到地下水资源高效利用和保护的目的,才能实现陕北能源化工基地产业的可持续发展。     

汕头第二过海水管工程顶管穿越障碍物技术

汕头第二过海水管工程中钢管顶管一次顶进长度2080m,是目前世界上一次顶进长度最长的钢顶管工程。该顶管成功地穿越不稳定的块石结构海堤和海底中风化花岗岩层两大障碍物,标志着顶管设计、施工技术的重大突破,拓展了顶管施工方式的应用范围。     

一株黑曲霉对磷矿石的风化作用

以一株分离于植物根际土壤且有较强溶磷能力的真菌研究其对磷矿石的风化作用。对该菌株的ITS序列进行PCR扩增及序列测定后,再结合该菌株的形态特征对其进行鉴定,结果为黑曲霉(Aspergillus niger)。用ICP-OES测定培养液中的Ca2+浓度,磷钼比色法测定可溶性磷的含量,电子探针、透射电镜和能谱仪分析菌株作用后的残留物。培养液中的Ca2+浓度由第3天的10.02mg/L增加到第30天的217.61mg/L,可溶性磷的浓度由第3天的5.37mg/L增加到第30天的921.37mg/L;风化过程中形成了大量的次生矿物草酸钙,大分子有机物形成的生物膜以及菌丝体穿插破坏矿物颗粒促进磷矿石的风化。表明该菌株对磷矿石有较强的风化能力,黑曲霉生长产生的生物物理破坏作用和胞外分泌物的生化降解作用是引起磷矿石风化的主要因素。     

Chemical homogeneity of high-Cr chromitites as indicator for widespread invasion of boninitic melt in mantle peridotite of Bir Tuluha ophiolite,Northern Arabian Shield,Saudi Arabia

The Bir Tuluha ophiolite is one of the most famous chromitite-bearing occurrences in the Arabian Shield of Saudi Arabia, where chromitite bodies are widely distributed as lensoidal pods of variable sizes surrounded by dunite envelopes, and are both enclosed within the harzburgite host. The bulk-rock geochemistry of harzburgites and dunites is predominately characterized by extreme depletion in compatible trace elements that are not fluid mobile (e.g., Sr, Nb, Ta, Hf, Zr and heavy REE), but variable enrichment in the fluid-mobile elements (Rb and Ba). Harzburgites and dunites are also enriched in elements that have strong affinity for Mg and Cr such as Ni, Co and V. Chromian spinels in all the studied chromitite pods are of high-Cr variety; Cr-ratio (Cr/(Cr + Al) atomic ratio) show restricted range between 0.73 and 0.81. Chromian spinels of the dunite envelopes also show high Cr-ratio, but slightly lower than those in the chromitite pods (0.73–0.78). Chromian spinels in the harzburgite host show fairly lower Cr-ratio (0.49–0.57) than those in dunites and chromitites. Platinum-group elements (PGE) in chromitite pods generally exhibit steep negative slopes of typical ophiolitic chromitite PGE patterns; showing enrichment in IPGE (Os, Ir and Ru), over PPGE (Rh, Pt and Pd). The Bir Tuluha ophiolite is a unimodal type in terms of the presence of Ru-rich laurite, as the sole primary platinum-group minerals (PGM) in chromitite pods. These petrological features indicates that the Bir Tuluha ophiolite was initially generated from a mid-ocean ridge environment that produced the moderately refractory harzburgite, thereafter covered by a widespread homogeneous boninitic melt above supra-subduction zone setting, that produced the high-Cr chromitites and associated dunite envelopes. The Bir Tuluha ophiolite belt is mostly similar to the mantle section of the Proterozoic and Phanerozoic ophiolites, but it is a “unimodal” type in terms of high-Cr chromitites and PGE-PGM distribution.     

Geochemical characteristics of stream sediments from an urban-volcanic zone,Central Mexico: Natural and man-made inputs

Geochemical characteristics of stream sediments [n = 31; Upstream section: Zahuapan River (1–12) and Atoyac River (13–20); Downstream section (21–31)] from Atoyac River basin of Central Mexico have been evaluated. The study focuses on the textural, petrography and chemical composition of the fluvial sediments with the aim of analyzing their provenance, the chemical weathering signature and their potential environmental effects. The fluvial sediments are mostly composed of sand and silt sized particles dominated by plagioclase, pyroxenes, amphiboles, K-feldspar, biotite, opaque and quartz. The sediments were analyzed for determination of major (Al, Fe, Ca, Mg, Na, K, P, Si, Ti), trace elements (As, Ba, Be, Co, Cr, Cu, Mo, Mn, Ni, Pb, Sc, V, Y, Zn, Zr, Ga) and compared with Upper continental crust (UCC), source area composition and local background values. The elemental concentrations were comparable with the average andesite and dacitic composition of the source area and the local background values except for enrichment of Cu (56.27 ppm), Pb (34 ppm) and Zn (235.64 ppm) in the downstream sediments suggesting a significant external influence (anthropogenic). The fluvial sediments of Atoyac River basin display low CIA and PIA values implying predominantly weak to moderate weathering conditions in the source region. Based on the provenance discrimination diagrams and elemental ratios, it is understood that the collected sediments are derived from intermediate to felsic volcanic rocks dominated in the study region. Metal contamination indices highlight the enrichment of Cu, Pb, Zn, Mo, Cr and S clearly indicating the influences from natural (weathering and volcanic activity) and external (anthropogenic) sources. Ecological risk assessment results indicate that Cr, Ni and Zn will cause adverse biological effects to the riverine environment.     

黔西北地区二叠纪玄武岩古风化壳常量元素的地球化学特征

通过对峨眉山玄武岩古风化壳进行野外调查、取样和分析测试工作,认为: ①贵州西部广泛出露峨眉山玄武岩,晚二叠世古气候温润潮湿,利于峨眉山玄武岩风化形成含Fe、Ti的黏土矿物和铝质黏土矿物的古风化壳,该风化壳受古地理环境和峨眉山玄武岩控制。②相对玄武岩而言,铝质黏土岩主量元素含量特征表现为富TiO₂、Al₂O₃,轻度亏损SiO₂,明显亏损TFe,其他主量元素大量流失; 铁质黏土岩主量元素含量特征表现为富TFe、TiO₂, 轻度富Al₂O₃,但相对于铝质黏土岩,TiO₂的富集程度偏低,SiO₂亏损明显,其他元素亦大量流失。③由于晚二叠世频繁的海侵作用,水位较高的区域,风化壳下部处于较还原的条件下,Fe被还原成易溶的二价状态或在有机质的作用下迁出风化壳,而Ti由于存在形式较为稳定,继续保存在黏土矿物中,与Fe发生分异; 局部水位较浅的氧化环境及重力分异作用下,黏土矿物与铁矿物由于比重差异而分选开来,形成Fe与Al、Ti的分异,并伴随铁矿、钛矿和铝土矿的富集。该富集规律的发现对寻找该区铁、钛和铝土矿有一定的理论指导意义。     

具产电性能光合细菌DH-3的分离及其对多种底物污水处理能力的评价

本文通过传统微生物分离培养方法从富营养化环境中分离培养出可高效处理多种底物的污水并具备胞外电子传递能力和产电潜力的兼性厌氧光合细菌。在光照培养条件下,利用改良的能够将光合细菌富集/分离的培养基分离培养光合细菌,从形态学和16S rDNA的分子生物学角度鉴定菌株。运用多个指标检测光合细菌处理不同底物的污水培养基的能力,如化学需氧量（chemical oxygen demand,COD）、总氮（total nitrogen,TN）、总磷（total phosphate,TP）,并在电化学工作站检测光合细菌的产电能力。结果表明,获取的光合细菌菌株DH-3与光合细菌类球红细菌（Rhodobacter sphaeroides）有97%的相似性。该菌株拥有在多种底物的污水培养基中生长的能力,其中在以乙酸为底物的培养基中生长最好。通过检测发现该菌株对污水的COD、TN和TP均具有较高的去除率。电化学工作站检测结果表明,菌株DH-3的最大产电流量能达到7.5mA/m²,最大功率密度达到0.056W/m²。由此可见,光合细菌DH-3在污水处理及资源再循环利用等方面具有十分重要的应用潜力。     

Review on Advances in Chemical Osmosis in Clayey Sediments

Osmotic phenomena refer to water and solute transport processes that occur when transport of solute molecules or ions is restricted by the porous medium relative to that of water molecules. Chemical osmosis and reverse osmosis/ultrafiltration are osmotic phenomena. The studies of “coupled flow” caused by chemical osmosis have been widely applied in many fields, such as earth science, environmental science and civil engineering. This paper provided a review of the considerable advances in the field of chemical osmosis and clay semipermeable membrane since the 1950s. We summarized the research progress of chemical osmosis in clayey sediments into three aspects: theoretical basis, experimental research and numerical model. In particular, the laboratory equipment and measurement methods of the chemico-osmotic efficiency coefficient σ were described,. The existing discontinuous models based on the ‘diffusive double layer’ theory were summerized, as well as the various control factors of σ. It increases with Cation Exchange Capacity (CEC), compaction pressure and decreases by the increasing of porosity and solution concentration. This paper also summerized the contimuum models based on non-equilibrium thermodynamics, which are used to explain and predict anomalies of hydraulic head pressure and salinity in clayey environments. For the future development of this discipline, it is critical to find a reliable method to confirm the σ value. It is also critical to emphasize the research on chemical osmosis in complex conditions and the influence of chemical osmosis on groundwater flow and solute transpotation. China has just stepped into this research area and more efforts should be made if significant progress is desired. This review will be helpful to further research on groundwater numerical simulation integrated with chemical osmosis in China.