DYNAMIC VARIATIONS OF WATER QUALITY IN TAIHU LAKE AND MULTIVARIATE ANALYSIS OF ITS INFLUENTIAL FACTORS

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Water-quality trends in White Rock Creek Basin from 1912-1994 identified using sediment cores from White Rock Lake reservoir, Dallas, Texas

Historical trends in selected water-quality variables from 1912 to 1994 in White Rock Creek Basin were identified by dated sediment cores from White Rock Lake. White Rock Lake is a 4.4-km² reservoir filled in 1912 and located on the north side of Dallas, Texas, with a drainage area of 259 km². Agriculture dominated land use in White Rock Creek Basin before about 1950. By 1990, 72% of the basin was urban. Sediment cores were dated using cesium-137 and core lithology. Major element concentrations changed, and sedimentation rates and percentage of clay-sized particles in sediments decreased beginning in about 1952 in response to the change in land use. Lead concentrations, normalized with respect to aluminum, were six times larger in sediment deposited in about 1978 than in pre-1952 sediment. Following the introduction of unleaded gasoline in the 1970s, normalized lead concentrations in sediment declined and stabilized at about two and one-half times the pre-1952 level. Normalized zinc and arsenic concentrations increased 66 and 76%, respectively, from before 1952 to 1994. No organochlorine compounds were detected in sediments deposited prior to about 1940. Concentrations of polychlorinated biphenyls (PCB) and DDE (a metabolite of DDT) increased rapidly beginning in the 1940s and peaked in the 1960s at 21 and 20 µg kg^-1, respectively, which is coincident with their peak use in the United States. Concentrations of both declined about an order of magnitude from the 1960s to the 1990s to 3.0 and 2.0 µg kg^-1, respectively. Chlordane and dieldrin concentrations increased during the 1970s and 1980s. The largest chlordane concentration was 8.0 µg kg^-1 and occurred in a sediment sample deposited in about 1990. The largest dieldrin concentration was 0.7 µg kg^-1 and occurred in the most recent sample deposited in the early 1990s. Agricultural use of chlordane and dieldrin was restricted in the 1970s; however, both were used as termiticides, and urban use of chlordane continued at least until 1990. Recent use of dieldrin and aldrin, which degrades to dieldrin, has not been reported; however, increasing trends in dieldrin since the 1970s suggest recent urban use could have occurred.     

山东荣成沽河流域水资源系统分析

流域水资源系统由降水产流，以及通过水文下垫面的转换，形成的地表径流和地下水流流组成。本文将复杂的沽河流域水 资源系统分解成多个子系统，利用频谱分析方法对各个水资源子系统的转换功能进行定量的分析刻画，并利用地下含水介质子系统的转换特征函数－频率响应函数求取水文地质参数，丰富了水文地质参数的获取途径。     

陕西凤县庞家河金矿床基本地质特征及成矿作用分析

阐述了庞家河金矿床的地层、构造控矿特征，研究了矿床的化学成分、微量元素及矿体、矿石的基本特点，分析了矿石及矿石矿物黄铁矿的O、S、Pb稳定同位素组成；认为庞家河金矿的成矿介质水为同生建造水，成矿物质来源于围岩上沉盆统下东沟组，矿床类型为热水溶滤成因的微细浸染型。     

沉积盆地流体—岩石相互作用研究的现状

沉积盆地流体－岩石相互作用研究主要是通过实验地球化学和岩石学，地球化学模拟方法开展的，综述了这一领域的研究现状，主要包括有机酸来源和分布及期 对矿物稳定性的影响，地层水成因与演化、烃类与岩石间的氧化还原反应、以及储层润湿性的变化等，并展望了其 发展趋势。     

山西离柳矿区奥陶系灰岩水环境质量分区及成因研究

本文对离柳矿区奥陶系灰岩岩溶地下水的环境质量进行了评价和分区，结合地质条件简述了各区的特点；还用地质－水文地质学相结合的理论，对各环境质量区形成的原因，进行了分析和研究，进而从理论上证明环境质量分区和选用标准的合理性。     

近场源二极激电法在贫硫银金矿床的应用效果

在管地贫硫银金矿床进行了近场源二极激电法的应用研究，获得了三高一低的次级低缓激电异常，即高ηｓ、Ｒ_２、Ｊｓ，低ρｓ，表明用次级参数表示的激电弱异常要明显，为增加矿量，提高地质找矿效果起了积极作用。     

Water quality impacts from mining in the Black Hills,South Dakota,USA

The focus of this research was to determine if abandoned mines constitute a major environmental hazard in the Black Hills. Many abandoned gold mines in the Black Hills contribute acid and heavy metals to streams. In some areas of sulfide mineralization local impacts are severe, but in most areas the impacts are small because most ore deposits consist of small quartz veins with few sulfides. Pegmatite mines appear to have negligible effects on water due to the insoluble nature of pegmatite minerals. Uranium mines in the southern Black Hills contribute some radioactivity to surface water, but the impact is limited because of the dry climate and lack of runoff in that area.     

碎石桩加固冷却塔地基效果的检测技术与质量评价

介绍了安阳电厂冷却塔碎石桩复合地基静载、动力触探、瑞利波法系列原位试验。根据试验结果，对冷却塔地基加固与改良效果及施工质量进行了评价。     

浙江杭嘉湖平原区环境地球化学研究

根据杭嘉湖平原区区域地球化学调查结果,对本区开展了区域和城市(杭州市)环境质量评价的环境地球化学研究。研究结果表明,杭嘉湖平原区区域环境质量和杭州市区环境质量良好,各环境质量区较好的反映各区内工业生产水平、人口密集程度、历史长短。通过对杭州市不同环境质量区内蔬菜的分析研究证明,杭州市区污染区内有害元素尚未对人体健康产生影响,但为防止今后出现超标现象,应当高度重视,加强土壤环境保护。