Major ion geochemistry of Godavari River at Rajahmundry, India     

K. Balakrishna S.S. Suvarna G. Srinikethan G. Mugeraya P.K. Krishnakumar 《中国地球化学学报》2006,25(B08):268-269

Detailed time-series studies on the major ion geochemistry of tropical peninsular Indian rivers are lacking. In this backdrop, a small stretch of the Godavari River, globally ranking 32nd in terms of total discharge, is chosen for sampling at its mouth. The objectives are： （1） to understand the natural and anthropogenic sources controlling the major ion chemistry of the Godavari River at Rajahmundry, （2） processes controlling the temporal variations in major ions over a period of two years, （3） comparison of total dissolved solid （TDS） fluxes and weathering rates at Godavari River with other major tropical rivers. A total of 47 surface samples were collected, bimonthly, at five stations in the Godavari at Rajahmundry spaced over a distance of 6 km for a period of two years. Water samples were collected in pre-cleaned PP bottles. Parameters like temperature, pH, conductivity, dissolved oxygen, alkalinity were measured on-site. Samples collected for analysis of major ions were processed within a few hours of collection by filtering through 0.45 mm pore size millipore filters. Filtered water samples for major ions were transported to the laboratory in cleaned 250 mL PP bottles. Sodium and K were measured on a Flame Photometer, Ca and Mg on a Flame Atomic Absorption Spectrophotometer, Cl, NO3, SO4 by Ion Chromatography and SiO2 on a spectrophotometer. Chemical weathering of rocks controls the major ion chemistry of the Godavari River at its mouth as indicated by the alkaline nature of the river and dominant presence of Ca, Mg and HCO3 ions. Ca/Mg and Na/Mg ratios point its source to a mixture of lithological assemblages of basalt, granite-granodiorite,  相似文献   

Strontium isotope composition of the Arno River Valley waters （Tuscany, Italy） as a natural tracer of water-rock interaction and mixing processes     

Barbara Nisi Orlando Vaselli Antonella Buccianti Giulia Perini Angelo Minissale Giordano Montegrossi Franco Tassi 《中国地球化学学报》2006,25(B08):273-273

Sr isotope studies of surficial waters have highlighted that differences in the ^87Sr/^86Sr ratio and Sr concentration are primarily caused by mixing of waters of various origins with specific isotopic and chemical characteristics, resulting from water-rock interaction processes. In this paper we reported the first Sr isotopic ratios, coupled with water chemistry, the measurement was carried out on samples related to （1） the Amo River （Tuscany, central-northern Italy）, between the source and the mouth, （2） the most important tributaries and to （3） the thermal water discharges seeping out in the southern part of the basin. The main goals are： a） to use the ^87Sr/^86Sr ratio as a discriminative parameter of source areas, b） to define its variation along both the main course and principal tributaries, and c） to estimate the effects of the mixing process of the different end-embers. The outcropping rocks in the Amo River Basin are predominantly sedimentary, mainly made up of Mesozoic limestones, Oligocene sandstones and Plio-Pleistocene marine-lacustrine formations. Triassic and Mesosinian evaporites crop out in the Elsa and Era reaches, whereas Paleozoic quartzitic formations occur in the Mrs. Pisani area. Strontium isotopic composition is generally controlled by lithology and does not seem to be affected by anthropic input and flow rate. The ^87Sr/^86Sr ratios in the Arno Basin vary between 0.707963 and 0.712743, the highest ratios being related to waters circulating in the Palezoic rocks and Oligocene sandstone formations. Less radiogenic values pertain to the Elsa and Era tributaries where contributions related to the dissolution of evaporitic sequences, and mixing processes with the thermal discharges have been distinguished. The tributaries show that water samples in the pristine area have higher ^87Sr/^86Sr ratios than the respective tributaries from which water samples were collected near the confluence. Eventually, water samples collected along the Arno River, close to the mouth, tend to have Sr isotopic ratios similar to those of the present seawater.  相似文献   

Kinetic research on the sorption of aqueous cadmium on carbonate hydroxyapatite     

Yu LIU Huanyan XU 《中国地球化学学报》2006,25(B08):104-105

The sorption of aqueous cadmium on carbonate-hydroxyapatite （CHap） is a complicated non-homogeneous solid/water reaction, From kinetic point of view, it can be described by two stages： at the earlier stage, reaction rate is so fast that its kinetic course is intricate, and at the later stage, the rate of reaction becomes slow and the process of reaction accords with one order reaction kinetic equation. Experimental results show that the relationship between reaction rate constant kl and temperature T accords to Arrhenius Equation, and the activation energy of sorption （Ea） is 6.075 J/mol and frequency factor （A） is 220 s^-1. At the same time, reaction rate constant kl increases with decreasing Cd^2＋ initial concentration, on the contrary, with increasing pH and CHap dosage.  相似文献   

Combining forms of heavy metal elements in Dianshan Lake sediments and their spatial and temporal variations     

Leping ZHENG Yuliang LIU Xiaoyan SHI Xianwen QIAN Lihua ZHOU Xiaoyan LIU Xinxin WU Weimin SUN 《中国地球化学学报》2006,25(B08):143-143

Dianshan Lake is one of the important water supply sources for Shanghai City. The contents of heavy metals in the sediments are obviously higher than those in the overlying water body. The contents of Pb in the sediments vary seasonally; with increasing depth, the contents of Cd, Pb, Cu, Cr and Fe show no variation generally, but Mn varies in the peak pattern. Cd, Pb, Cu, Cr and Fe in the sediments are present predominantly in sludge phase, but iron and manganese oxide form of Pb and organic matter-sulfide form of Cu are their respective preferential combining forms. Manganese is present largely in exchangeable form, iron-manganese oxide combined form and sludge form. The contents of the various forms of Cd, Pb, Cu, Cr and Fe tend to vary with changing season and depth. The contents of exchangeable forms of Fe and Mn vary with depth in the peak-like pattern.  相似文献   

Mercury levels in surface waters of six reservoirs in the Wujiang River     

《中国地球化学学报》2006,25(B08):151-151

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Seasonal variations of adsorption/desorption equilibrium concentrations of P at water-sediment interface in the Meiliang Bay, Taihu Lake, China     

Xia JIANG Xiangcan JIN Dongmei LIU 《中国地球化学学报》2006,25(B08):164-165

Seasonal variations of adsorption/desorption equilibrium were investigated by collecting overlying water and seasonal sediment from the Meiliang Bay, Taihu Lake, China. At the same time, seasonal variations of TP and P fractions＇ concentrations in the initial and end of adsorption experiment were also carried out. In addition, the effects of temperature on the P translocation process were also conducted and discussed. The following conclusions were obtained： The sequence of adsorption/desorption equilibrium concentrations of P at water-sediment interface was spring〈winter〈autumn. In sediment the concentrations of TP decline. Concentration P decreased with temperature.  相似文献   

Hydrologic and hydraulic characteristics of the Yellow River and impact of flow and sediment diversion     

Dong WANG Shaoming PAN Jichun WU Qingping ZHU Chang LIU 《中国地球化学学报》2006,25(B08):168-169

In the history, the Yellow River nurtured Chinese civilization. It is respected as the ＂ancestor of the four large rivers in China＂ and praised as ＂the mother river of China＂. At the same time, the Yellow River is regarded as ＂the misery of China＂ and considered as the most complex river hard to control in the world. Today, the Yellow River is also one large river greatly influenced by human activities in the world. The safety of the Yellow River, particularly flood control, is always the most important issue for governing and developing the country. Great achievements have been made after many years of efforts for controlling the Yellow River. However, since the nineties of 20 century, some new problems occurred, such as sharp reduction of flux to sea, dry rivercourse, worsen environment, etc. Rapidly shrinking riverbed and two-level perched stream are disadvantageous to flood safety especially. The new concepts and new practices are urgently needed to control the river. Therefore, the Yellow River Conservancy Committee of Ministry of Water Resources had continuously carded out flow and sediment diversion each year from 2002 to 2005. To timely probe into the new issues produced after flow and sediment diversion, and in order to deepen the understanding of rules for the Yellow River＇s water and sediment and provide reference and experience to the researchers for other large rivers, five hydrologic and hydraulic characteristics of the Yellow River, such as lack of water, much of sediment, different resources of water and sediment, inconsistency between water and sediment and frequency of sink switching and route changing, are described. Flow and sediment diversion of the Yellow River is also reviewed. Under flow and sediment diversion,  相似文献   

赴埃及访问总结     

《气象科技合作动态》2006,(4):5-15

为了加强国家级培训中心的能力建设和国际培训与交流，提高培训水平，拓展培训领域，加强管理和师资队伍建设，学习其他国家先进气象水文教育培训的经验，经中国气象局批准，并应埃及气象局局长董事会（Board of Directors）代理主席Magdy Ahmed Abbas的邀请，以中国气象局培训中心副主任刘国平为团长，人事处处长李洪臣、教育科研处副处长赵庆生、科技培训部主任俞小鼎、  相似文献   

Groundwater Systems and Eco-hydrological Features in the Main Karst Regions of China     

LU Yaoru  ZHANG Feng''e  LIU Changli  TONG Guobang  ZHANG Yun Chinese Academy of Geological Sciences  Beijing Institute of Hydrogeology  Environmental Geology  Chinese Academy of Geological Sciences  Shijiazhuang  Hebei 《《地质学报》英文版》2006,80(5):743-753

1 Introduction Karst topography is widespread in China (Lu et al., 1973; Lu, 1986a), but its basic features are quite different in the main karstified areas in southern and northern China (Lu, 1999, 2003). The karst development appears to differ not only in the karst geomorphological types but also in the forms of the different karst water systems. The eco-hydrological features have obviously been influenced by human activities. The eco-hydrogeology is thus of great importance to study. Th…  相似文献   

科技之窗     

《水文》2006,26(6):95-95

本期“科技之窗”栏目,主要介绍中国水利学会2006学术年会和2006年度大禹水利科技奖水文水资源和信息化类获奖项目统计信息；同时简介了中国水利学会水文专业委员会承办的水文分会场有关情况。  相似文献