Hydrological Controls and Freshening in Meromictic Soap Lake,Washington, 1939-20021

Kallis, Jahn, Leo Bodensteiner, and Anthony Gabriel, 2010. Hydrological Controls and Freshening in Meromictic Soap Lake, Washington, 1939-2002. Journal of the American Water Resources Association (JAWRA) 46(4): 744-756. DOI: 10.1111/j.1752-1688.2010.00446.x Abstract: The chemically stratified layer of naturally formed meromictic lakes exhibits unusual and often extreme physical and chemical conditions that have resulted in the evolution of uniquely adapted species. The Columbia Basin Irrigation Project appears to have had a marked effect on the hydrology of Soap Lake, a meromictic lake in the Grand Coulee of central Washington. The relation of hydrology to salinity was assessed by analyzing water budgets before and after the introduction of the irrigation project. Before irrigation, water gains were balanced by losses; after irrigation began groundwater gains approximately doubled. To manage lake levels and reduce groundwater influx, wells were installed to intercept groundwater. Although the hydrological cycle has been restored to pre-irrigation conditions, the meromictic character of the lake continues to change. Interception wells remove 10 to 16 Mm³ of groundwater annually, but influx continues based on change in the monimolimnion. From 1958 to 2003 the chemocline descended 1.1 m and the volume of the monimolimnion from 698,000 m³ to 114,000 m³. Annual loss of volume is occurring at a rate of 1.9% since 1958. Although groundwater interception wells are maintaining the volume of the entire lake, the recession of the chemocline indicates that conditions that have maintained meromixis at Soap Lake are currently not in equilibrium.     

An Aquifer Classification System and Geographical Information System-Based Analysis Tool for Watershed Managers in the Western U.S.1

Payne, Scott M. and William W. Woessner, 2010. An Aquifer Classification System and Geographical Information System-Based Analysis Tool for Watershed Managers in the Western U.S. Journal of the American Water Resources Association (JAWRA) 46(5):1003-1023. DOI: 10.1111/j.1752-1688.2010.00472.x Abstract: Aquifers and groundwater systems can be classified using a variety of independent methods to characterize geologic and hydraulic properties, the degree of connection with surface water, and geochemical conditions. In light of a growing global demand for water, an approach for classifying groundwater systems at the watershed scale is needed. A comprehensive classification system is proposed that combines recognized methods and new approaches. The purpose of classification is to provide groundwater professionals, policy makers, and watershed managers with a widely applicable and repeatable system that reduces sometimes cumbersome complex databases and analyzes to straightforward terminology and graphical representations. The proposed classification system uses basin geology, aquifer productivity, water quality, and the degree of groundwater/surface water connection as classification criteria. The approach is based on literature values, reference databases, and fundamental hydrologic and hydrogeologic principles. The proposed classification system treats dataset completeness as a variable and includes a tiered assessment protocol that depends on the quality and quantity of data. In addition, it assembles and catalogs groundwater information using a consistent set of nomenclature. It is designed to analyze and display results using Geographical Information System mapping tools.     

铁炭复配修复地下水中NO_3~--N的条件研究

采用了铁炭复配修复地下水中NO3--N,探讨了实验条件对修复效果的影响。结果表明,在pH值近中性条件(初始pH 6.42)下,反应时间为1 h时NO3--N修复率达到60.85%;Fe/C=1∶1时介质最佳用量分别为4~5 g;Fe/C=1/1.5时修复率为72.80%;反应速率在高振荡强度下大于低振荡强度;氧化铜的催化效果最好,可使修复率提高7.5个百分点。铁炭复配介质修复地下水中NO3--N是有效可行的,修复率随反应时间的增加而提高,在Fe/C=1∶1时修复率与介质用量呈正相关,无限减小Fe/C比并不能无限提高修复率,振荡强度对修复具有显著影响,低振荡强度下的修复过程较高强度存在滞后现象,并非所有金属氧化物催化剂对铁炭修复NO3--N均有促进作用。     

不同碳源和泥龄对反硝化聚磷的影响

在4个SBR装置(1#~4#)中,对4种不同比例的丙酸/乙酸合成废水采用厌氧/缺氧方式驯化富集反硝化聚磷菌(DPB),研究了碳源浓度和污泥龄对除磷的影响。实验结果表明:(1)厌氧段碳源COD浓度越高,释磷越充分,溶解性正磷酸盐(SOP)去除率越高;但当碳源COD浓度超过某个浓度值时,未反应完全的有机物残留于后续缺氧段对缺氧吸磷产生抑制作用。(2)污泥龄SRT=15 d时,活性污泥的性能较好,达到了较好的除磷效果。(3)在相同碳源浓度和相同的污泥龄下,随着丙酸/乙酸比例的提高,SOP的去除率逐渐的降低。说明在厌氧/缺氧环境下,碳源中丙酸比例的提高不利于系统中磷的去除。高乙酸含量的碳源更适合反硝化除磷系统。     

Concentration and characterization of plutonium in soils of Hubei in central China

To study the Pu concentration and isotope ratio distributions present in China, the ^239+240Pu total activities and ²⁴⁰Pu/²³⁹Pu atom ratios in core soil samples from Hubei Province in central China were investigated using Accelerator Mass Spectrometry (AMS). The activities ranged from 0.019 to 0.502 mBq g⁻¹ and the ^239+240Pu inventories of 45 and ∼55 Bq m⁻² agree well with that expected from global fallout. The ²⁴⁰Pu/²³⁹Pu atom ratios in the soil ranged from 0.172 to 0.220. The ratios are similar to typical global fallout values. Hence, any close-in fallout contribution from the Chinese nuclear weapons tests, mainly conducted in the 1970s, must have either been negligible or had a similar ²⁴⁰Pu/²³⁹Pu ratio to that of global fallout. The top 10 cm layer of the soil contributes ∼90% of the total inventory and the maximum concentrations appeared in the 2-4 cm or 4-6 cm layers. It is suggested that climatic conditions and organic content are the two main factors that affect the vertical migration of plutonium in soil.     

Characterization of plutonium in deep-sea sediments of the Sulu and South China Seas

Anthropogenic Pu isotopes are important geochemical tracers for sediment studies. Their distributions and sources in the water columns as well as the sediments of the North Pacific have been intensively studied; however, information about Pu in the Southeast Asian seas is limited. To study the isotopic composition of Pu, and thus to identify its sources, we collected sediment core samples in the South China Sea and the Sulu Sea during the KH-96-5 Cruise of the R/V Hakuho Maru. We analysed the activities of ^239+240Pu and the atom ratios of ²⁴⁰Pu/²³⁹Pu using isotope dilution sector-field inductively coupled plasma mass spectrometry (SF-ICP-MS). The ²⁴⁰Pu/²³⁹Pu atom ratios in the sediments of both areas (inventory weighted mean: 0.251 for the South China Sea and 0.280 for the Sulu Sea) were higher than the global fallout value (0.178 ± 0.019), suggesting the existence of Pu from the Pacific Proving Grounds in the North Pacific. Low inventories of ^239+240Pu in sediments were observed in the South China Sea (3.75 Bq/m²) and the Sulu Sea (1.38 Bq/m²). Most of the Pu input is still present in the water column. Scavenging and benthic mixing processes were considered to be the main processes controlling the distribution of Pu in the deep-sea sediments of both study areas.     

区域经济重心及 COD、SO_2、TSP排放重心演变路径分析——以江苏省为例

运用重心模型,采用1996~2006年江苏省经济和环境数据,计算出各年份GDP、工业产值、COD、SO ₂和TSP排放重心坐标,揭示江苏省经济重心和环境污染排放重心变化轨迹及演变规律,以期为江苏省环境宏观战略决策及生态省建设提供理论参考。研究表明,经济重心总体上向东南方向偏移,GDP重心偏移距离为14.81 km,工业产值重心偏移距离为12.84 km;经济重心在南北方向上的偏移程度大于东西方向的偏移程度。环境污染排放重心也向东南方向偏移,COD和TSP排放重心轨迹呈现较大变化,SO2排放重心轨迹变动较小;COD排放重心偏移距离为79.26 km,SO₂排放重心偏移距离为15.73 km,TSP排放重心偏移距离为42.24 km;各污染排放重心轨迹在不同时段表现出不同特点。COD、SO₂和TSP排放重心相对于经济重心偏向于西北方向,且COD排放重心近年来明显趋向于工业产值重心;COD排放重心和TSP排放重心与经济重心存在着强正相关.     

基于元素毒性赋值的模糊数学环境质量评价

利用模糊数学方法,根据元素毒性的大小进行权重赋值,对成都经济区近地表大气尘进行地球化学环境质量评价。结果显示：不同城市中,成都、乐山、眉山的大气环境质量较好,处于一级清洁级别;眉山、雅安的大气环境质量处于二级安全级别;德阳的大气环境质量已经处于三级警戒级。不同地区中,绵阳和眉山的大气环境质量较好,处于一级清洁级别;德阳和雅安处于二级安全级别,成都和乐山处于三级警戒级.     

我国农产品贸易中的虚拟耕地交易分析

虚拟耕地是指隐含在农产品贸易中,生产这些农产品过程中所必需占用的土地资源,有意识的在国际农产品贸易中实施虚拟耕地战略,对于平衡国内耕地赤字、保障粮食安全,发挥我国农产品在国际市场上的竞争优势具有重要的理论指导意义。首先介绍了虚拟耕地的定义及其量化方法,接着分析计算了我国谷物、油籽、棉花等几类主要农产品单位重量的虚拟耕地含量,在此基础上,对当前农产品进出口贸易中虚拟耕地的交易现状及未来发展趋势作了分析和预测。结果显示：近10 a来虚拟耕地净进口量出现持续增长,2006年,通过农产品国际贸易净进口虚拟耕地16602903.1 hm²,约占当年全国耕地总面积的12.77%。同时,虚拟耕地净进口量在今后若干年仍将保持增长态势。     

湖北“两圈”区域发展可持续性评价与预测

利用可持续发展指数（SDI）对湖北“两圈”各市州发展现状进行了评价,而后利用9年的人均生物资源生态承载量年平均增长率、人口年平均增长率和足迹承载量比值年平均增长率及2006年相关数据对未来44年进行了预测。结果表明,截至2006年底,湖北省有一半以上国土面积的生物资源开采超过当地土地负荷,人均生物资源生态承载量持续下降,资源日益紧张,呈不可持续发展;武汉城市圈2006年生物资源生态足迹超出生物资源生态承载量的32%;鄂西生态文化旅游圈（简称：鄂西生态圈）除襄樊、荆州、荆门因人口多,生物资源生态足迹较大等原因导致SDI值较高外,其他市州的SDI值均较低;神农架的SDI最小;武汉城市圈人均生物资源生态承载量呈负增长,人口控制较好,足迹承载量比值增长较快;鄂西生态圈人均生物资源生态承载量呈负增长,增长速率大于武汉城市圈和湖北省,人口控制较差,足迹承载量比值增长较慢;按照现有发展模式,无论是武汉城市圈还是鄂西生态圈,无论其当前发展是可持续性还是不可持续的,未来他们都将进入不可持续的发展状态。因此,对“两圈”进行规划时要根据各自发展现状制定长期、科学的发展规划.