辽河三角洲土壤中石油类含量光谱分析初探

石油类物质对土壤的污染在油田区域内是一个普遍存在的问题。全面了解土壤中石油类物质含量是评价土壤石油污染的前提条件。对土壤石油污染评价的传统方法是在野外实地进行大量土壤采样,然后在试验室内分析石油类物质的含量。文中提出了利用少量野外土壤石油类物质样品,并结合野外光谱测量的方法对土壤中石油类物质进行分析的新方法。该方法应用于辽河三角洲,具有快速、省钱、省时、省力的特点,能对土壤中石油类物质含量进行宏观分析。满足了油田开发对土壤及环境污染评价的需要,并能为制定油田开发管理保护对策提供辅助信息。     

基于GIS的长江中下游地区洪灾风险分区及评价

国内外近几年的发展表明,在所有可能避免和减轻自然灾害的措施中,最简单有效的方法就是通过在科学研究基础上进行风险区划,将自然灾害管理提高到风险管理的水平.在长江流域数字化地图的基础上,选取不同重复期(20,50,100年),及包括1870年历史洪水和1931,1935,1954,1991,1995,1996,1998,1999和2002年共10次洪水,借助Arcview地理信息系统的空间分析和叠加功能,对长江中下游地区的洪水灾害危险性进行了初步评价.首先参考洪水灾害淹没图和相关历史文献记录资料,构建10次洪水受灾县(市)分布图;其次对这10次洪水受灾县(市)分布图进行叠加,得到长江中下游地区洪涝灾害风险性评价图.分析表明:长江中下游地区洪水风险的分布是有规律的,而且具有明显的地理意义.有4个明显的高危风险区,分别是洞庭湖、鄱阳湖两湖平原的湖滨地区和公安以下的长江中游河段的沿江一带,尤其是荆江河段以及两江相夹地势低洼的江汉平原;沿高危风险区外侧为高风险地区,重点在汉江下游、资、沅、澧水、清江流域、皖沿江地区以及太湖流域的部分地区;沿长江于高危风险和高风险地区两侧分别为风险较小地区;其他地区对于洪水灾害而言则为安全地区.评价结果与长江中下游的实际情况基本吻合.     

塔里木河中游输水堤防外的地下水质变化分析

针对塔里木河中游输水堤防修建与生态保育的问题,结合对沙子河和阿其河两个断面地下水质的监测资料的分析,对输水堤防修建后堤防外地下水质的时空变化进行了探讨,揭示了在输水堤防影响下堤防外地下水质变化的初步规律.结果表明：沙子河断面和阿其河断面洪枯期地下水矿化度的变化规律由于堤防的修建而被改变,同样在堤防外侧,由于无地表水经过,沙子河断面地下水矿化度远高于在有生态闸定期放水的阿其河断面,因此,生态闸建设对抑制由于输水堤防影响而导致的水质修建具有积极作用.     

Class: an Essential Aspect of Watershed Planning

A study of a watershed planning process in the Cache River Watershed in southern Illinois revealed that class divisions, based on property ownership, underlay key conflicts over land use and decision-making relevant to resource use. A class analysis of the region indicates that the planning process served to endorse and solidify the locally-dominant theory that landownership confers the right to govern. This obscured the class differences between large full-time farmers and small-holders whose livelihood depends on non-farm labor. These two groups generally opposed one another regarding wetland drainage. Their common identity as “property owner” consolidated the power wielded locally by large farmers. It also provided an instrument – the planning document – for state and federal government agencies to enhance their power and to bring resources to the region. The planning process simultaneously ameliorated conflicts between government agencies and the large farmers, while enhancing the agencies’ capacity to reclaim wetlands. In this contradictory manner, the plan promoted the environmental aims of many small-holders, and simultaneously disempowered them as actors in the region’s political economy. An erratum to this article is available at .     

The Water Fluxes of the Yellow River to the Sea in the Past 50 Years, in Response to Climate Change and Human Activities

Since the 1970s, the water fluxes to the sea of the Yellow River have declined significantly. Based on data of precipitation, air temperature, the measured and “natural” river flow, the water diversion and consumption, and the areas of erosion and sediment control measures over the drainage basin, water fluxes to the sea of the Yellow River are studied in relation with the influences of changing climate and human activities. The Yellow River basin can be divided into different water source areas; multiple regression indicates that the variation in precipitation over different water source areas has different effect on water fluxes to the sea. In the period between 1970 and 1997, averaged air temperature over the whole Yellow River increased by about 1.0°C, from 16.5°C to 17.5°C, a factor that is negatively correlated with the water yield of the Yellow River. Water diversion and consumption has sharply increased and resulted in a significant decline in the water fluxes to the sea. Since the 1960s, erosion and sediment control measures have been practiced over the drainage basin. This factor, to a lesser degree, is also responsible for the decrease in water fluxes to the sea. A multiple regression equation has been established to estimate the change in water fluxes to the sea caused by the changes in precipitation, air temperature, water diversion and consumption, erosion, and sediment control measures, indicating that the contribution of water diversion and consumption to the variation in annual water flux to the sea is 41.3%, that of precipitation is 40.8%, that of temperature is 11.4%, and that of erosion and sediment control measures is 6.5%.     

BASE FLOW TRENDS IN URBANIZING WATERSHEDS OF THE DELAWARE RIVER BASIN1

Rapid land development is raising concern regarding the ability of urbanizing watersheds to sustain adequate base flow during periods of drought. Long term streamflow records from unregulated watersheds of the lower to middle Delaware River basin are examined to evaluate the impact of urbanization and imperviousness on base flow. Trends in annual base flow volumes, seven‐day low flows, and runoff ratios are determined for six urbanizing watersheds and four reference watersheds across three distinct physiographic regions. Hydrograph separation is used to determine annual base flow and stormflow volumes, and nonparametric trend tests are conducted on the resulting time series. Of the watersheds examined, the expected effects of declining base flow volumes and seven‐day low flows and increasing stormflows are seen in only one watershed that is approximately 20 percent impervious and has been subject to a net water export over the past 15 years. Both interbasin transfers and hydrologic mechanisms are invoked to explain these results. The results show that increases in impervious area may not result in measurable reductions in base flow at the watershed scale.     

千河下游水体-沉积物重金属空间分布、风险及影响因素

为了研究千河下游水体-沉积物重金属污染特征、风险程度及其影响因素,采集千河下游表层沉积物19份及水样20份,使用电感耦合等离子体质谱仪(ICP-MS)测定8种重金属(As、Cd、Cr、Cu、Mn、Ni、Pb和Zn)含量,分析了水体中重金属含量和健康风险,对沉积物重金属空间分布及污染特征进行探析,以DEM、气温和降水等11种因子为自变量,结合地理探测器和地理加权回归模型对沉积物重金属污染影响因素进行空间分异探究.结果表明,千河下游8种水体重金属浓度均未超过地表水环境质量标准Ⅱ类水体标准,其中Pb元素变异系数为3.11,浓度高值区主要集中于东岭冶炼公司和凤翔火车站周围.水体成人致癌物Rc均值为7.72E-06,呈较轻风险程度,儿童致癌物Rc均值为1.17E-04,呈强风险程度,成人与儿童非致癌物风险均为可承受风险程度,儿童R总的高值主要集中在凤翔火车站周边,呈较强风险程度;千河下游沉积物重金属除As和Mn外,其余6种元素均超过陕西省土壤背景值,其中Cd元素含量均值为1.12 mg·kg^-1,是陕西省土壤背景值的12倍,Cd、Zn和Pb污染较严重,主要分布在长青村、南湾...     

河水-地下水交互带沉积物中抗生素和代谢产物提取方法优化及其分布特征

河水-地下水交互带是污染物发生富集、降解和转化等生物地球化学过程的重要场所.抗生素作为一类广泛关注的有机污染物,探索其在交互带中的分布特征对认识特殊生境下污染物迁移转化过程具有重要意义.由于交互带氧化还原条件变化敏感,沉积物组成特殊,建立了一种有效提取交互带中22种抗生素及4种磺胺类代谢产物的前处理方法,并对样品初始状态、提取温度、提取液p H值以及有机提取溶剂进行了优化.同时对汉江下游河水-地下水交互带沉积物中的抗生素含量进行分析,结果表明,采用p H=3的乙腈/乙二胺四乙酸二钠(Na₂EDTA)-Mcllvaine缓冲液(1∶1,体积比)对未经氧化的沉积物原样在40℃条件下进行3次微波提取,目标抗生素的回收效果最好.汉江下游交互带沉积物中共检出11种抗生素,其中以土霉素(OTC)和氧氟沙星(OFL)为主,最高检出含量分别为6.77 ng·g^-1和5.81 ng·g^-1.不同交互剖面中抗生素含量的垂向分布差异较大,主要与沉积物岩性、抗生素理化性质和地表水-地下水交互作用等影响因素有关.     

松花江流域水生态环境质量评价研究

采用生物完整性指数(IBI)法评价松花江流域的水生态环境质量。对25个候选生物参数进行敏感度分析、Pearson相关性分析,最终筛选出由总分类单元数、EPT分类单元数、EPT密度、敏感种分类单元比例、敏感物种数量、Hilsenhoff生物指数(HBI)6个核心参数构成的IBI评价指标。采用95%分位数法建立了IBI评价标准,将IBI评价结果划分为5个等级:大于35.84为优,26.88~35.84为良好,17.92~26.88为一般,8.96~17.92为较差,小于8.96为很差。结果表明,建立的IBI评价方法适用于松花江流域水生态环境质量评价,松花江流域各位点30.0%生物状况为优和良好,23.3%为一般;46.7%为较差和很差,说明流域内近一半区域的水生态质量存在不同程度的受损。流域生境质量主要处于一般-良好的状态;水质处于轻度污染。