Metal contamination of active stream sediments in upper Weardale,northern Pennine Orefield,UK

In the Upper Weardale area the headwaters of the River Wear bisect the Northern Pennine Orefield, where Pb-Zn-F-Ba vein-type mineralisation has been exploited since the Roman Conquest. The area contains evidence of open pit, underground and hydraulic mining of base metal ores, associated mineral processing and smelting, exploitation of ironstones during the industrial revolution, recent extraction of fluorite and active quarrying. The aim of this study was to determine the extent of modern sediment contamination arising from these past activities. Samples of active stream sediments were collected from all major drainage channels at 1 km intervals. The sediments were analysed for Pb, Zn, Ba, Mn, Fe, Co, Ni, Cu, Cr, As, Sb, Ag and compared to data from earlier regional geochemical surveys of low order drainage samples using ArcView software. The significance of contamination levels was assessed using the Ontario aquatic sediment quality guidelines. Our results indicate widespread contamination of some major drainages by Pb, Mn, Zn and As at concentration levels anticipated to significantly affect use of the sediments by benthic organisms. Furthermore, Pb contamination shows persistence in stream sediments downstream towards agricultural areas of the floodplain and drinking water abstraction points, above which interaction with colliery mine water discharges may occur.     

贵州百花湖沉积物中磷的再迁移作用

本文通过百花湖沉积物柱芯不同化学相磷含量分布，孔隙水地球化学及早期成岩模式和通量估算等研究，揭示了磷在早期成岩过程中迁移，转化和富集规律，揭示某些湖泊表层沉积物几厘米磷蓄积浓度的增加与磷在早期成岩过程中的行为有关。     

生物操纵理论在浅水湖泊治理应用中的现状与展望

水域富营养化现象已经成为中国及世界范围内一个较为突出的环境问题.利用生物操纵法在水体富营养化防治和浅水湖泊的生态修复中具有较为广泛的探索应用,也取得一定的治理成效.文章综述了生物操纵的产生和发展,分析生物操纵(biomanipulation)和非经典生物操纵(non-traditional biomanipulation)理论的原理、应用条件及局限性,并从沉水植物、虑食性鱼类和双壳贝类的作用和应用现状分析和探讨了各生态位生物在单一生物操纵下的适用条件及实际应用中遇到的问题.最后对生物操纵技术组合技术进行合理展望,以期为中国富营养化湖泊治理和修复工作提供参考.     

Heavy Metal Sediment Load from the City of Stockholm

A transect of upstream lake sitesand downstream coastal sites surrounding the cityof Stockholm, capital of Sweden, wereinvestigated for heavy metals in sediments.Concentrations of Cd, Cu, Hg, Pb and Zn increasedclose to the city. In the most central areas ofStockholm, sediment deposition was increasedabout 5-fold for Cd, Cu, Hg and Pb and 3-fold forZn, as compared to the surrounding areas. Thesediment load from the city was estimated bycorrecting for a background concentration. It canbe concluded that most of the load of Hg and Pbwas trapped in the sediments close to the citywhile Ni, Cu, Cd and Zn to a higher degree weretransported through the archipelago towards theBaltic Sea.     

Urban Land-Use Influences on Transport of Heavy Metals to Lakes and Concentrations in Fish

Water, Air, &; Soil Pollution: Focus - To investigate the urban land-useinfluences on transport of heavy metals to lakesand metal concentrations in fish liver (perch andcrucian carp), ten lakes...     

金坛市饮用水源地保护方案研究

钱资荡是金坛市目前直接饮用水源地,根据环境监测结果,它已处于中营养化后期。借鉴国内外先进的湖泊管理经验,运用系统工程的思想和方法提出了切实可行的金坛市饮用水源地保护方案。该方案由4个工程子系统组成,（1）截污工程：在岸丘桥和南州桥位置各筑一节制闸（而岸丘桥工程又是首选工程）,以封住湖泊两头入流,杜绝污染物进入水源地的截污工程;（2）引水工程：是截污工程的配套工程,利用一游长荡 湖来补充水量,并对3个引水工程设想进行了系统分析,推荐涵管方案,同时将长荡湖作为该市战略水源地一并纳入保护体系中;（3）湿地生态处理工程：对进入荡区前的芦苇区进行综合整治,发展以芦苇为主的湿地生态处理工程;（4）环湖绿色自然保护带工程：包括建设围湖芦苇荡、环湖林带、绿色食品基地以及污泥处置。最后还提出了三级水域保护区范围、水域行政管理体系建设以及工程方案分步实施计划。     

Heavy Metal Transport and Behavior in the Lower Columbia river, USA

The primary objective of this study was to evaluate temporal changes in heavy metal content of lower Columbia River sediment following terminated or reduced soluble heavy metal loading from the world's largest lead-zinc refinery and mining districts in the USA and Canada. Sediment cores were collected from two fine sediment depositional sites (∼600 km downstream) in August 1999 and were analyzed for total metal content, texture, and age/dating parameters. Zinc, cadmium and lead contents in 1999 declined by only a factor of two over their depth profile maxima (dated as between 1970 and 1980). In sharp contrast, more than a 10-fold decrease in dissolved metal loading occurred during this same period. Zinc in filtered Columbia River water at downstream locations also declined by > 10-fold, consistent with the reduced upper river solute-metal loading. Once soluble metal releases are reduced or terminated, the solute half-time in Columbia River water is months versus ∼20 yr for adsorbed metals on surficial (or resuspended) bed sediments. The much slower rate of decline for sediment, as compared to the solute phase, is attributed to resuspension, transport and redeposition of irreversibly bound metals from upstream sedimentary deposits. This implies downstream exposure of benthic or particle-ingesting biota can continue for years following source remediation and/or termination of soluble metal releases. Accordingly, contaminant contents of both particulate and solute phases of river water, as well as sediment core sections, are suggested for assessing long-term biotic exposure/response to mitigation activities in the Columbia River and similar fluvial ecosystems.     

Assessment of the exposure of two fish species to metals pollution in the Ogun river catchments, Ketu, Lagos, Nigeria

The concentrations of metals (Ca, Cd, Fe, Mn, Pb and Zn) were determined by flame atomic absorption spectrophotometry in water, sediments and fish samples in the Ogun river catchments, Ketu, Lagos, which is an important bird nesting, fishing and drinking water source. The results show that the southern tip bothering the Lagos lagoon is where the highest metal concentrations are found in the fish species (Tilapia sp. and Chrysichthys sp.), whereas the Agboyi creek segment near the lagoon with higher surrounding human population density recorded higher levels of metals in sediments and water samples. The two fish species accumulated different amounts of metals. However, the differences were not statistically different at p < 0.05. There is a significant correlation (p < 0.05) for Cd concentration in water. The concentrations of Pb in sampling points 3 and 4 as well as Cd, Mn and Fe in all six sampling points exceeds the World Health Organization (WHO) limits for drinking water. Levels of metals obtained for sediments are within the range reported for Nigeria’s river sediments. Based on this study, the human risks for heavy metals in the harvested fish species from the Ogun river catchments, Ketu, are low for now as the concentrations were below the recommended Food and Agriculture Organization (FAO) maximum limits for Pb (0.5 mg/Kg), Cd (0.5 mg/Kg), and Zn (30 mg/Kg) in fish.     

ESTIMATING EVAPORATION FROM UTAH'S GREAT SALT LAKE USING THERMAL INFRARED SATELLITE IMAGERY1

ABSTRACT: Water surface temperatures can be obtained from satellite thermal remote sensing. Landsat and other satellites sense emitted thermal infrared radiation on a regular basis over much of the earth's surface. Evaporation is accomplished by the net transport of mass from the water surface to the atmosphere. The evaporative transfer predominantly determines the water surface temperature. Hence, there should be good correlations between evaporation and surface temperatures. Previous investigations on Utah Lake with satellite-derived temperatures and pan- and model-derived evaporation values have produced good correlations. However, more study was required with additional satellite data and evaporation measurements for saltwater conditions. The applicability of this method for estimating evaporation on Utah's Great Salt Lake was of particular interest at this time because of the unprecedented rise of this terminal lake. Satellite thermal data and evaporation data from four different years were obtained for the Great Salt Lake and the surrounding region. More than 350 correlation and linear regression analyses were performed on the temperature and evaporation data. The lake salt concentrations were also factored into the analyses in several different ways. The correlation results were generally very good and a methodology for using satellite-derived water surface temperatures along with salt concentrations was developed to estimate evaporation.     

富营养化水体中底泥释磷的影响因素及其释放机理

磷是湖泊富营养化的主要限制因子,本文综述了沉积物中磷的赋存形态,释放机理及其影响因素.内源磷的赋存形态主要分为铝磷、铁磷、钙磷及有机磷.磷释放受pH值、溶解氧、生物、温度、扰动5种因素影响.对富营养水体内源磷释放的影响因素及其机理进行研究可为富营养化水体的治理提供理论依据.