顶空气相色谱法测定地表水中吡啶

采用顶空进样、毛细管柱HP -INNOWAX分离、GC -FID测定地表水中吡啶。水样顶空时通过加碳酸钠盐大幅度降低了检出限 ,最低检出浓度达到 0 0 2mg/L。本法加标回收率为 96 5 %～ 10 1% ,变异系数为 7 8%～ 9 8%。     

表面活性物质对HPMA阻垢缓蚀性能的影响

表面活性物质的加入可明显提高水解聚马来酸酐(HPMA)的阻垢、缓蚀性能,且不同表面活性物质影响程度不同,通过剩余硬度法测定阻垢性能,静态失重法测定缓蚀性能,从而比较异丙醇、葡萄糖酸钠对HPMA阻垢、缓蚀性能的影响。实验结果表明,异丙醇与HPMA复合使用时效果较好,阻垢率达到 79 0 %,缓蚀率达 70 7%,且阻垢率随Ca2 + 浓度增大而增大。     

Change in Fish Fauna as Indication of Aquatic Ecosystem Condition in Río Grande de Morelia–Lago de Cuitzeo Basin, Mexico

Chirostoma charari and C. compressum, and they are presumed extinct. Twelve (63%) of the remaining species had declines in distribution. Sixteen (80%) of the 20 localities sampled had lost species. The greatest declines occurred in Lago de Cuitzeo proper and in the lower portion of the Río Grande de Morelia watershed. Species losses from the lake were attributable to drying and hypereutrophication of the lake because of substantial reductions in the amount and quality of tributary inputs, whereas losses from the Río Grande de Morelia watershed were the result of pollution from agricultural, municipal, and industrial sources, especially in the region around the city of Morelia. Three localities in the upper portion of the Río Grande de Morelia watershed—Cointzio reservoir, La Mintzita spring, and Insurgente Morelos stream—contained most of the remaining fish species diversity in the basin and deserve additional protection. Fish faunal changes indicated major declines in the health of aquatic ecosystems in the Morelia–Cuitzeo basin.     

Validity of Performance Criteria and a Tentative Model for Regulatory Use in Compensatory Wetland Mitigation Permitting

The purpose of this paper is to develop the principles for a manageable and practical set of performance criteria that will reasonably assure no net loss in a situation in which it cannot be absolutely assured. To this end, the performance criteria proposed for 116 compensatory wetland projects on file with the Army Corps of Engineers in San Francisco, between 1988 and 1995, were examined. The trends discerned in the project proposals were analyzed and evaluated in light of the current state of wetland science. Specific suggestions for the development of uniform criteria in each of four major wetland types—riparian, perennial tidal, perennial nontidal, and seasonal—are discussed, and a system of regulation tying qualitative assessment with quantitative requirements is outlined as a reasonable solution to the enforcement of the no-net-loss policy.     

EFFECTS OF CLIMATE CHANGE ON HYDROLOGY AND WATER RESOURCES IN THE COLUMBIA RIVER BASIN1

ABSTRACT: As part of the National Assessment of Climate Change, the implications of future climate predictions derived from four global climate models (GCMs) were used to evaluate possible future changes to Pacific Northwest climate, the surface water response of the Columbia River basin, and the ability of the Columbia River reservoir system to meet regional water resources objectives. Two representative GCM simulations from the Hadley Centre (HC) and Max Planck Institute (MPI) were selected from a group of GCM simulations made available via the National Assessment for climate change. From these simulations, quasi-stationary, decadal mean temperature and precipitation changes were used to perturb historical records of precipitation and temperature data to create inferred conditions for 2025, 2045, and 2095. These perturbed records, which represent future climate in the experiments, were used to drive a macro-scale hydrology model of the Columbia River at 1/8 degree resolution. The altered streamflows simulated for each scenario were, in turn, used to drive a reservoir model, from which the ability of the system to meet water resources objectives was determined relative to a simulated hydrologic base case (current climate). Although the two GCM simulations showed somewhat different seasonal patterns for temperature change, in general the simulations show reasonably consistent basin average increases in temperature of about 1.8–2.1°C for 2025, and about 2.3–2.9°C for 2045. The HC simulations predict an annual average temperature increase of about 4.5°C for 2095. Changes in basin averaged winter precipitation range from -1 percent to + 20 percent for the HC and MPI scenarios, and summer precipitation is also variously affected. These changes in climate result in significant increases in winter runoff volumes due to increased winter precipitation and warmer winter temperatures, with resulting reductions in snowpack. Average March 1 basin average snow water equivalents are 75 to 85 percent of the base case for 2025, and 55 to 65 percent of the base case by 2045. By 2045 the reduced snowpack and earlier snow melt, coupled with higher evapotranspiration in early summer, would lead to earlier spring peak flows and reduced runoff volumes from April-September ranging from about 75 percent to 90 percent of the base case. Annual runoff volumes range from 85 percent to 110 percent of the base case in the simulations for 2045. These changes in streamflow create increased competition for water during the spring, summer, and early fall between non-firm energy production, irrigation, instream flow, and recreation. Flood control effectiveness is moderately reduced for most of the scenarios examined, and desirable navigation conditions on the Snake are generally enhanced or unchanged. Current levels of winter-dominated firm energy production are only significantly impacted for the MPI 2045 simulations.     

完全均匀混合质量平衡水质模型在滇池中的应用

介绍了完全均匀混合假设下以质量平衡为基础的湖泊水质模型,运用滇池的实测数据对模型进行了参数率定、验证,给出了模型在滇池水质预测中的应用实测,最后讨论了模型的几个假设条件对滇池的适应性。实例研究表明,该模型可适用于滇池水质有机污染长期浓度预测。      

固相微萃取-气相色谱法测定饮用水及其水源水中的氯酚

利用固相微萃取(SPME)-气相色谱法(GC)联用技术测定饮用水及其水源水中的氯酚．优化萃取温度、萃取平衡时间、酸度、离子强度等实验条件．所建方法简便、精确,自来水和太湖水中均检测到氯酚。     

环境治理中光催化剂的失活与再生

催化剂失活是影响光催化过程用于污染治理经济实用的关键因素。对近几年来国内外环境污染控制中光催化剂的失活现象及其原因进行了综述．分析了液相和气相光催化反应体系中催化剂失活后再生的方法．特别是对气相光催化反应中水蒸汽的影响进行了讨论。     

高浓度难降解乳化废水湿式氧化影响因素研究

在2L高压间歇反应釜中,系统地研究了湿式氧化对乳化液废水的CODCr,TOC去除效果及影响因素。研究表明:温度是影响湿式氧化效果的关键因素,湿式氧化温度以220℃为宜,进水CODCr质量浓度为48000mg L时反应2h,CODCr和TOC去除率分别达86 4%,79 5%;供氧不足氧化受到显著限制,供氧量以(1 0～1 25)p(O2) 为宜;该法在较宽浓度范围内仍具有良好的处理效果;进水pH值对有机物氧化影响较小。